08-19-09: I've struggled for a long time to understand solid-state - I mean, REALLY understand...
Here's an article about LEDs, but the explanation of how the semiconductor crystal lattices interact in quantum wells finally turned on the light-bulb in my head (sorry about the pun):
http://www.spectrum.ieee.org/semiconductors/optoelectronics/the-leds-dark-secret/1 >08-19-09: Wow!! My head is spinning so much has changed so fast in three short weeks...now it looks like I'm going to Nebraska again (or maybe Oklahoma or Iowa)....I just finally threw in the towel on trying to make a living in crazy AZ in my profession, and realized I had to get to the midwest where my experience is appreciated. So, my bench remains packed up in boxes, and it will be at least another month before I can unpack and set up again, and finally post on the Heathkit amps and the other projects.
Now, back to messing about with tube electronics!!! My projects now, to be posted here, are:
1. High-Voltage (I'm not kidding) Triode Direct/Coupled Electrostatic Amplifier and Speaker. Oh, yeah!!! NO output transformer (eek! ack!) - the triode plate connected directly to the electrostatic speaker heh heh heh ;) I'm working on the power supply right now (20 Kilovolts...heh heh heh), and will be posting both the failures and successes soon.
2. Very serious and comprehensive mods to the classic Heathkit AA-151 tube amp. Purists be warned: cover your eyes if you don't like complete and total upgrading of an amp... (It only took a year and a half and I had to disappoint a whole bunch of people...but between using Allen Wright's single-ended design for the phono preamp section, getting rid of the global negative feedback, getting rid of an entirely unnecessary amp stage in the old Williamson design, doubling up the output EL-84's for much more power with less distortion and far better damping factor, and moving the power supply back outside of the amp (which enables doubling the output tubes), I think I've finally got the final design. No more remote control; that turned into just far too much hassle and expense and complexity...maybe someday.
When I get my bench set back up, and as I complete each of the half-dozen AA-151's I still have half-completed, I'll check to see if any of the original orderers want theirs (finally!), and, if not, put them on here for sale. As well as post all the mods, of course.
3. Homebrew General Coverage Ham and Shortwave Receiver, all tube. This is a REALLY FAR-INTO-THE-FUTURE project, don't hold your breath, but it will be fine...someday (I will be posting soon, though, on some interesting experiments with different ways of making variable inductors and capacitors that I've not seen in classic (or modern) designs...
4. And, yeah, I'm still chipping away at bringing SENSE AND ORDER to the list of links on the right...oh, well, like I said before, perfection takes...time
Tip for the Day (now you don't have to send in your $10 to the guy who ripped off "the mom who discovered the secret to whitening teeth"): to whiten teeth, mix a strawberry with 1/2 teaspoon baking soda: if you were wondering if other fruits than strawberries could be used - combined with baking soda - for whitening teeth - the answer is yes, probably: any fruit that has malic acid in it will probably work. Strawberries, are, however, a heckuvalot easier to mash up - an important consideration if you can get them easily. Fruits with malic acid include: Strawberries, Green Apples, unripe apples other varieties, green grapes, probably any unripe citrus fruit, rhubarb (!) - the edible stalks, not the leaves or roots!!...and like that. Probably just about any unripe fruit would work, most fruits have SOME malic acid in them, especially when they're still unripe. Just mix a little mashed fruit with roughly the same amount of baking soda, brush onto teeth, sit 5 minutes, brush off and rinse thoroughly. If the fruit doesn't work...try another type! (Or you could just get malic acid at a wine-making store, but note caution that follows): DON'T OVERDO: any whitening process can remove enamel, and if you overdo it, you'll get really sensitive teeth, maybe damage them, so pay attention and be a little cautions, OK?
6-21-09: I have started reorganizing the links on the right by listing them numerically. It's the only way, with this blogware, I can keep them in order...
I'm putting them into categories. It's a WORK IN PROGRESS ;) - I work on this a little bit almost every day:
01. through 20. The TOP 20 information articles or sites for tube amp DIY'ers...nothing for sale here, just MUST-READ, CLASSIC or CUTTING-EDGE info. (Yeah, there's more than twenty...:)
(For sites with stuff for sale, if they don't have a separate section for tech info, they don't get listed here; look in the 20's for the "for sale" pages of the same site):21. through 40.
The next-to-top 20 sites/pages - or the commercial side of site with great tech pages - that I find most useful for various pieces of information, projects or products. So far, all of these are MUST READS for anyone just getting into tubes, to get the best information without the baloney (no ebarf scam artists here, as far as I know....:)41. through 60.
The
best places I know of to GET PARTS TO MAKE STUFF - parts/tubes/mosfets/etc. All of these are commercial, and all are places I go to for parts frequently. It's odd, but I - and lots of other DIY'ers, I'm sure - have found that you just can't get all the right parts for a particular project from one place, even places as huge as digikey. And, even though you can buy a little cheaper (in quantity) from massive warehouses like digikey and mouser, etc., the personal service and wealth of info at places like Angela, Antique and Triode Electronics is well worth the extra pennies. IF I LEFT SOMETHING OUT, PLEASE LET ME KNOW, I DON'T MEAN TO LEAVE OUT ANY LINK TO A DECENT SITE. The more the merrier.
61. through 70. To Be Determined...(I forget)71. through 80. Places to GET VACUUM TUBES (some of it repeats from 21-40; most of them sites devoted to vacuum tubes primarily, including places world-wide for Russian, rare British, Australian, etc., vacuum tubes. 71's: Sites for vacuum tubes, that cover just about everything; 76's: Sites for Direct Heated Triodes (U.S./Canada/Australia/England); 77's: Sites for Russian or Eastern European vacuum tubes;
(more categories to come)....:) NEW PROJECT: I am happily :) working on a direct coupled tube amp electrostatic speaker. Oh, I'm psyched about this one. No output transformer, of course (aack! eeeek!). A very high voltage triode (REALLY high voltage, no joke), with the stator driven directly from the plate. Not to worry, such high resistance that it couldn't even kill your cat...although the dog will definitely think twice about ever peeing on your speakers again....heh heh heh :)
So, it's a huge electrostatic speaker, with it's own tube amp built into the base and direct coupled to the electrostatic speaker, no transformer. Then a line amp is in the center, with a cable to each tube amp/electrostatic speaker combo. CD's, phono's, radio, internet, TV, go into the center line amp.
The center line amp will be anything you want to use, doesn't much matter. I am also in process with a center line amp that is remote controlled and has a zillion tone controls (bass, low-mids, high-mids, treble, pentode/UL/triode, variable global negative feedback, etc.), but the tube amp/electrostatic speaker combo comes first. P.S.: I recently found Alibris, which has cheap copies of Robert Tomer's book from 1960, "Getting the Most Out of Vacuum Tubes"...it's linked on the right, but here's the link again...go there, buy it, read it. http://www.alibris.com/booksearch?binding=&mtype=&keyword=getting+the+most+out+of+vacuum+tubes&hs.x=0&hs.y=0&hs=SubmitKeep in mind that this book was written by an engineer who collected vast amounts of data from industries that used even vaster numbers of vacuum tubes in industrial equipment, including audio and RF, that cost big money to service and repair when something broke down...so, his information may be from 1960, but it's scientific, it's specific, it's sensible, and it's based on the best tubes ever made by giants such as RCA and GE. So, if you REALLY want to know how to design in order to protect tubes and give them the longest life possible, buy this book, read it, and follow the principles. And ignore the dunderheads who, because it's convenient, and who have never REALLY done the necessary science, tell you that you don't REALLY have to delay B+ before the filaments are hot, or that preventing filament turn-on surge REALLY doesn't matter, or the rest of the long list of baloney people try to tell you just because they're too lazy or too cheap to do it right. If I just pissed someone off, good. They need to wake up.
On the other hand, if you don't believe me, by all means, knock yourself out, forget the delay and the surge protection....far be it from me to try to tell the world how to do whatever the heck it wants to do (as one gets older, one sees the futility of trying to change belief systems...)
I'll write an article on this soon, including EASY ways to delay B+ and prevent filament turn-on surge, but for now I'll leave you with one final little shocker: Tomer presents scientific data that demonstrated that tube testers do nothing but greatly increase the rate of early tube failure!!
He documented that in many tube testers, the transconductance of the tube was significantly reduced during the first test and the lifespan was shortened. Industries that had maintenance programs that pulled tubes for testing on a regular basis had a far higher premature failure rate than if they left the tubes in place and monitored circuit parameters. Interesting, huh?
So, buy your tubes NOS from Antique or another good supplier, and forget those "tested" tubes on ebarf (if you really want to save an old NOS, the first time you fire it up, just heat the filament for half an hour to several hours...no B+. THEN add B+ very slowly. After that, it should be fine. The idea is to get the getter activated, clear out any vapors that might have formed, and burn off any dust or debris that might be hanging in there. Throwing a 60 year old NOS into a tube tester that hasn't been heated up since it left the factory and hitting the test button is a great way to destroy it FOREVER....just a word to the wise ;) ------------------------------------------------------------------------- I guess I'll have to take back what I said about wigix - it may be a good alternative to ebarf for mass-produced commodities - but it's not going to help tube amp DIY'ers a bit. Just on a lark, I asked to be permitted to be a Sub-category expert for tube amps - not because I'm an expert, there are hundreds of guys far more expert than me - but just to see what would happen...plus I would have done my very best to include every tube amp, past and now...but I just got the brush-off. Wigix told me that tube amps were "Vintage" products, and that Wigix doesn't DO "Vintage"...so I guess I'm not going to DO Wigix!!!!!
I guess we're just pretty much stuck with ebarf.....EXCEPT......
There is a site that both sells tube amps and has an auction section for amps and audio equipment:
Most of the stuff on audiogon is waaaaaaaay too expensive for me...but I did see some stuff at quite reasonable prices, along with some interesting auctions, so I would recommend you give them a look-see. They claim to have a huge viewer-ship, so maybe it will become the tube DIY'er's alternative to ebarf. NOTE: I'm still finishing up the amps I started modding Lo, These Many Months Ago...(now a year!!)...but they're close to done now, so I will be adding new articles, and finishing some of the ones I half-wrote, sometime....... Yeah, I know, a year seems incredible...but wait till you see them. Every time I thought I had the design finalized, I realized there was onnnnnnnnnnnne more tweak I could add, and it kinda...got out of hand. But it really (no, really!) is done now, and the first amp is about to ship, the rest in line right after, and THEN I can post all the yummy pictures. The pictures are gonna knock your eyes out, not to mention the plans, schematics and close-ups of the CCS construction, NMOS source followers construction, etc. ("It ain't boastin' if yuh done it", unknown...if you know the source of the quotation, by all means let me know :)
I now have an HP 3581A Wave Analyzer, and a PC-based spectrum analyzer, so look forward to some realistic distortion analyses, where I'll start at the input to the amp, and show what happens to the signal each step of the way...and then we'll understand better what ends up coming out the end. It's all (well, mostly all :) about topology.
Until then, do check the links from time to time, I'm adding INCREDIBLE links all the time on the right, just SUPERB sites. The web is a truly amazing place.
We must keep the internet free!! Free to access, free to post, free to download, free of censorship (except for illegal things like exploitation of children, of course), FREE OF CORPORATE INFLUENCE, because with a free internet, all things truly are possible. I believe the internet is the next step in the development of human civilization, and holds promise for people everywhere (except places like China and - sigh - Russia right now, where the repressive governments have imposed internet censorship - but I do believe all this will change, humans will put up with censorship for only so long).
Check out the link to a truly beautiful Japanese DIY'er's site I recently added (although I still haven't been able to figure out what his name is!...if anyone reads this who reads Japanese, and can figure it out, please let me know. You CAN post now at the end of the article, it just goes through me first.....
Hi, if you're like me, you're looking for something really special in audio - with a truly open mind - and the willingness to DIY - Do It Yourself (to some extent) in order to make superb affordable.
And you like things done well just for the fun of it - there doesn't have to be a universal truth, it doesn't have to be "the only" way to do it - but it IS superbly done - and you do it for the sheer enjoyment of it.
Someone once said something like this: "You can be assured manufacturers will find the cheapest way to do things fairly well. Not the best, just the cheapest." And, unless you're rich and can afford to spend $100,000 on a pair of speakers, that's just the way it is - you can have OK and cheap, or you can have some of the best and ridiculously expensive -
or you can have superb - almost the best - and do most of it yourself.
This site is how to DIY superb audio from my own perspective. There are other sites that also show how to DIY superb audio, but from different perspectives. I'm not claiming my way is better! Just a different way of looking at it. That's why I'll have a list of great sites on the right hand side and great projects on the left side, when I get to it (right now I have to drive Cameron to his friend's house). My starting purpose may surprise you a little:
I believe in tube amps completely supported by solid state engineering. The key word here is "supported" by...nothing solid state in the signal path...except mosfet source followers, which add or take nothing...but vacuum tubes working with SS Constant Current Sources, buffered by mosfet source followers, control grids of tubes biased by op amp servo circuits that are NOT in the signal path, and outputs from vacuum tubes not through a transformer, but through a CCS'd voltage-to-current mosfet source follower converter.
But, as I've worked on this site, I've found a second purpose that, is to me, just as important: being a resource site for others, that helps you find great stuff on the web: great forums, great projects, great educational material, great vendors. So, my list of favorite links on the right side is LONG and getting longer. I find everyone of these links useful, frequently. I come to my own home page all the time just to use my own links!! Note: all the links are listed on the right, grouped as best I can. COMING: all the same links organized into folders on the LEFT side of the page.And, there is a third purpose for this site: mods to Heathkit AA-151 amps, a place I can document ways to improve the old amps. If you have suggestions, please feel free to send them, I think I have all the comments links at the end of the articles working now...comments have to go through me. I'm easy to get along with, and I like different perspectives and ideas, so please don't be put off by the security of the link...it's just to stop spammers.
So, this site is intended to be: 1. a resource full of links to great tube amp sites and great "audio" sites on the web world-wide, 2. a resource for showing ways of making tube amps that use SS engineering, and 3. it's intended to document a whole mountain of cool mods to the venerable, sweet-sounding old Heathkit AA-151 - improving it without losing it's inherent sweet tone (mostly due to the combination of it's output EL-84's in UL PP and very good output transformers) - as well as, later, the AA-100 (which is a pentode PP higher power amp but not sweet-sounding at all....so, PEOPLE, please stop bidding these things up on ebarf! They're not that good - actually, pretty bad - without serious modding!). And, except for modding old tube amps - mostly the Heathkits - primarily the AA-151 and, later, the AA-100 - this site is also going to be dedicated to something that is even more heretical than using SS to support tubes: we're going to get rid of the output transformer altogether.
Which doesn't mean I'm against tube amps with output transformers...far from it. It's just that there are already so many GREAT tube amps with ouput transformers, including the old McIntosh MC-30, probably the greatest of all time, but also including more modern tube amps with output transformers, such as the ones on Max's AngelFire site (see links on right), there's just no point in me adding more. What I WILL do is include lots of links to great sites for traditional tube amps (traditional in the sense of using output transformers), including the kits at Antique, Angela and Triode, to name just a few. Actually, now that I think about it, I am going to eventually do a mod for the old AA-151's and AA-100's that will get rid of the output transformers (even though they're quite good ones)...heh heh heh ...and which will transform them (heh, get it? transform?) from 14 watts per channel to .... oh .... hundreds of watts per channel....or pretty much as many watts as you want. Want a thousand watts per channel?....this can be done heh heh heh....
So, the name of this website is kind of an "inside joke" - this site is mostly about building tube amps without output transformers - by using a different method to transform voltage to current - which is what you have to do somehow in order to drive speakers. I had a revelation about this recently after years of modding old tube amps and reading articles about various new designs - I realized that all of these designs had one problem in common - how expensive - or less than perfect if cheap - output transformers are, and how you have to spend a lot of money on a really big one to get really, really good audio, and how much engineering you have to do to make the amp work well with the transformer, even if it's a great one.
I think some people, who have an engineering nature, like the challenge of how to get around the disadvantages of an output transformer. I also think that many DIY'ers find that particular part of amp design the most difficult....it's just an observation I've made over the years, that how to handle choosing the impedance ratio and how to use global feedback and how to design Zobel networks and how to get good bass without spending a fortune or losing the treble, and then on top of that how to figure out which transformer to buy and how much to spend...it just all becomes very difficult.
Now, McIntosh figured out how to solve the output transformer problem years ago, by using "four-build" (four layers of insulation) magnet wire, adding a cathode feedback winding that was wound alongside the plate windings (each wire side-by-side, this was serious stuff), and using that cathode feedback as essentially 100% local feedback, so that there was no transformer distortion to bother measuring. If you get ahold of an old MC-30, and know how to fix it up, by all means do so. But please don't drive the prices up any higher than they already are...despite it's perfection, it's still an old tube amp that needs complete recapping...at the least.
Now, if I were to become a DIY OPT-winder-master, I'd just copy the McIntosh method, except maybe add a separate screen winding for UL at a lower bias point...and I admit I keep being tempted......but the same problem that McIntosh had still exists: core materials, such as M-6 lams (laminations), are far from perfect...and must be bought in bulk (translation: train-car loads)...to be economical for the DIY'er...and better core materials cost a FORTUNE!...and magnet wire with truly high-voltage insulation CAN be had, but not cheap. No, I don't mean those magnet wire coils sold on surplus sites or sites that specialize in small parts. Wind up a McCintosh OPT design with that stuff, and be prepared for fireworks! It really is NOT SAFE to put plate windings and cathode windings side-by-side unless you have really, really good magnet wire and know how to do it right, so.....fogeddaboudit.
Criminey, now I really WANT to DIY a true Mac OPT, but add the screen winding, just to show off....but I'll do my best to STIFLE the impulse...
It's no accident that a lot of forums spend a lot of time on figuring out how to make a tube amp sound half-way decent using the cheaper of the Hammond and Edcor and Triad output transformers - most of us tube DIY'ers are broke! We can't afford good iron! If we could afford really good iron, heck, we'd just buy a great amp and be done with it! (Except for the few rich hobbiests who do this out of curiosity...let me know if you know who they are....:)
So, if you didn't know before, I'll just let you know briefly that output transformers do have faults, and that in my opinion the task of compensating for those faults sometimes does more harm than good, and you still have all that weight and expense.
Just the main problems: distortion (from the inherent hysteresis loop of the core), phase shifts (which can cause oscillations or ringing), capacitive coupling between windings (decreases the treble, distorts the treble more), insufficient damping factor (which allows the speakers to control the amp instead of vice versa - like the tail wagging the dog - causing peaks and nulls in the frequency output of the speakers), and core saturation (limits the bass output, and can, in the deep bass at high power peaks, actually make the output transformer act as a short when the inductive reactance is lost! - if this happens too badly, the output tubes can be damaged and the output transformer can actually be burnt out.)
What is the main strategy used to minimize the distortion of the output transformer? Global negative feedback. What does this do? Loses musical content, subtle musical information. We've known for a good forty years now how to make an amplifier have virtually zero distortion...but that doesn't mean the amp sounds good. In fact, many of us find music through an amp with low distortion, due to a lot of negative feedback, to be lifeless, dead, dull.
How is the problem of phase shift causing oscillation dealt with? Limiting bandwidth. RC damping networks, which are as much magic as math (the math will get you half-way there, and then you have to "cut-and-try" until it works.) Hams and electronic engineers are all over RC damping networks, that's just play for them, but for the rest of us...ehh...you have to do a lot of messing about, and maybe you get it really nice, maybe you don't.
How is the problem of impedance peaks and dips from the speakers compensated for by the amp? Usually, not at all. Hope for the best. Buy different speakers. In truth, most of the time this is not a big issue. But it can be, especially when lower impedance ratios are used to get more power, or if you happen to accidentally get the wrong speakers for the transformers in your amp.
Finally, how is the problem of core saturation dealt with? Usually, by limiting how low the amp can go...or by spending a lot more money for a lot more core....which also means a lot more copper...which means, as the price of copper continues to go up, prices going ever higher.
Now, does all this matter very much with a guitar amp? No, not usually. Heck, the distortion sounds great, and some saturation just adds to the "soul-fullness" of the guitarists sytle.
Does it matter listening to classical, jazz, rock? Heck yeah, you only have to hear a great system once to never be satisfied with the cheap one you have.
So, when I personally look at the biggest obstacle to getting great sound out of a DIY amp without spending a ton of dough, the most obvious component to me is the output transformer. I saw this plain as day on a tube forum just this week: a newbie joins, after getting hold of some tubes, and wants help finding a design to build. He gets some great suggestions, but quickly runs into the main roadblock: the cost of the output iron. After rejecting, as far as I could tell, all the suggestions as costing too much for the output transformers, we don't hear from him again. I can feel his pain. There are PLENTY of great amp designs on the web...but most of them have one thing in common: be prepared to spend at least several hundred dollars for the output iron, in some cases many hundreds more.
I did spend the better part of last year sourcing lams and bobbins and frames and reasonably priced magnet wire to start winding my own, and got some help from one of best DIY output transformer makers in the world - and then gave up. You know why? Because there's a certain amount of "magic" in designing and winding a really good transformer. The guys that make them know this, and they don't keep it a secret either. When someone says they'll just wind one themselves, the custom winders just laugh and say, "Good Luck!" So, I decided life wasn't long enough - at least I don't have enough life left! - to become an expert in transformer winding - remember, the only way to find out if a particular design tweak works is to wind the entire things up and try it! And did you ever try UNwinding the wire so maybe you could use it again? Hah! Hah hah heeeh hah hoooo...no, fogeddaboutit, that's copper down the drain. So, buying iron: the cost of good output iron really does discourage me from building new amp designs....and I really don't feel like putting tons of time and effort into how to make a cheap OPT sound half-decent. So, enough! No more output iron for me.
However, we now have a way of getting rid of the output transformer , but still use tubes for the voltage amplification part of the amp. Mosfets. So, in the amp designs that I will be posting, the function of transforming the voltage amplification that has happened inside the tubes will be handled, not by a transformer, but by a mosfet. This opens up some very interesting options indeed. Such as immense power without having to use a zillion output tubes or scary high-voltage plate supplies (like a kilovolt or more...the 813 really ought to be run at 2 kilovolts, and I am considering it, because such an amp with a mosfet voltage-to-current output would be literally impossible to clip - you'd turn your speakers into flaming infernos first (which is a problem, I admit)). Now, you can have a hundred watt amp easy, and instead of spending several hundred bucks per channel on output transformers to handle all that power, you only have to spend twenty or thirty bucks per channel - but it's still a tube amp. For a thousand watts per channel you'll have to spend a hundred bucks per channel on mosfets, but you can't even get output transformers for such an amp - maybe from Sowter, who can probably make just about anything, given enough money - but your only other choice would be to put ten of the biggest Hammonds in parallel. Which would be nuts.
I also have become a firm believer in bi-amping or even tri-amping, even though I do believe in most cases bi-amping is quite sufficient. Actually, bi-amping or tri-amping is probably only need if you're using a tube amp with an output transformer - to get the bass out of the transformer, where it sucks all the energy from the amp - but it can make sense with a mosfet output amp also, allowing you to use smaller mosfets for the higher frequencies, where the gate capacitance has more effect, and huge mosfets for the bass, where the gate capacitance's effect on slew rate doesn't matter, AND getting rid of the crossover in the speaker between the mid and the bass, which is A: worse (phase shift like crazy) and B: usually made of the cheapest components possible.
A little detour (this will eventually be a category by itself): the reason I have fallen in love with bi-amping especially for tube amps with output transformers is simple: a tube amp (with OPT) can only handle midrange and treble superbly. It has a hard time with the deep bass. Unless you spend enormous money on really heavy (and I do mean heavy) output transformers...or use tons of negative feedback (ugh...a little is fine, a lot is...NOT), any tube amp that must use an output transformer to couple the tubes to the speakers will have floppy bass, especially the deep bass. Put an oscilloscope across the output, and feed square waves and you'll see what I mean: from about 300 Hz down, it's progressively distorted - in fact, a transformer cannot transmit DC. 20 Hz is really close to DC.
If you put direct current into the input of a transformer, what do you get from the output? Nothing. Think about it: audio goes up to 20 thousand Herz (cycles per second). At 300 Hz, you're pretty close to DC compared to 20 thousand! So, we've gotten used to floppy bass, and just accept it as part of tube amp culture, instead concentrating on how gorgeous and warm the midrange is and how clear and shimmery the treble is. But, unless you have an output transformer the size of a VW (OK, I'm exaggerating a little here ), you are NOT going to get really good bass, certainly not really good deep bass. Look at power line transformers, that have to step voltage down at 60 Hz, which is really deep bass. Those things are huge! It's not just because they have to transmit a lot of current - although they do - it's also because they have to operate at a frequency so close to DC. The cores have to be huge to not saturate. They're also super easy to design compared to an audio output transformer, because they don't have to also transform midrange and treble. See? That's why output transformers are so problematical - they have to do too much. 20 Hz to 20 KHz, without distortion and phase shift and loss at low and high ends, is just too much to ask of a transformer....thus global negative feedback, and the compromise between weight (bass) and copper (treble), and the devil's choice of cheap versus expensive versus very, very expensive.
So, to me, the solution is not to ask your tube amp to make deep bass, for me there are too many compromises to achieve that, and I can't afford great output iron - and despite my macho attitude a few years ago (I don't care how heavy the ^(%^$#!! thing is)- to me, the answer is very simple: put a crossover into the amp right before the phase splitter that drives the push-pull output tubes (assuming it's push-pull, we'll talk about that in another blog) and split off the bass from 310 Hz down, so the tube amp only has to drive the speakers from about 300 Hz to 20 KHz. Now, THAT WORKS. As for that bass output? Easy. Buy a subwoofer or woofer that has it's own SS amp (that's what transistor amps are GOOD for - subwoofers/woofers) and feed the bass to that. (Just make sure the powered subwoofer or powered woofer has a frequency range from 20 or 25 Hz up to at least 500 Hz, probably better 1 KHz - not a subwoofer that is only for the deepest bass, from like 20 to 55...some of them are for just those deepest tones). Then mess with the positioning of the speakers for the amp and the speakers for the bass, and then.....ahhhhhhh, enjoy.
Before you get worried about the cost of the subwoofers: cheap ones made for cars will work fine. Yeah, you can get better, but cheap ones for cars will still work a lot better than that tube amp with it's wimpy output transformer, believe me.
One last word on this: many will say, hey, I've been listening to music all my life through a tube amp without splitting off the bass, and it sounds fine to me. There are three reasons for this. First, you're used to it. It's amazing how - if there's no good alternative at hand - the brain can adjust itself to terrible sound and enjoy it. Especially if the music is something you really like. I remember once on a long road trip, late at night, managing to tune in some distant station playing one of the great symphonies - I don't remember which one it was, but I'm sure it was either a Beethoven, Brahms Fourth, Dvorak's Ninth, or Schubert's Unfinished - the reception was terrible, full of noise, some other station in the background, there was no bass and the treble was covered by the hiss, and I still enjoyed every moment of it. So, we adjust to lousy sound. Sometimes because we have to, and do so consciously and cheerfully. Sometimes because we're become accustomed to it over a long time without anything better around. But that doesn't mean you have to spend the rest of your life missing out on great bass. It DOES make a difference - especially the frequencies between 200 and 300 Hz.
A second reason people have accepted bass through a tube amp is that the ear actually accepts a lot of distortion from the bass without protesting. If the midrange is beautiful, our brain is engineered to not miss the bass terribly. It's just part of neuroacoustics.
There is a third reason, though, that I think might surprise you. Bass speakers make a lot of second harmonic distortion. Don't worry, our ears like second harmonic (h2) just fine. When a distorted bass spike comes from the tube amp to the speaker, the speaker does such a lousy job of reproducing that awful spike that the resulting sound is actually a second-harmonic-distortion-approximation of what the bass waveform actually was! So, all in all, tube amps have gotten off easy when it comes to truly good bass response for almost a hundred years now.
But I still believe that if you ever hear a good bi-amped system, you'll be amazed at how suddenly bass is so clear, articulate, full of detail and thunderous all at the same time, not the floppy background grumble you're used to. (Note to Max: yeah, I'm probably over-exaggerating a little...)
So, when I mod an old Heathkit amp, what is one of the things I do? Install a crossover, that's what, and let your Heathkit handle the midrange and treble, and let a separate self-powered subwoofer take care of the deep bass. The same for my 6BQ6GBT amp below, and for my 813 amp below: a crossover built right into the amp, and let the bass go to separate subwoofers. Trying to make a tube amp handle everything from deep bass to high treble is like trying to shovel sand against the tide, in my opinion. By the way, the circuit for that crossover has already been done by Rod Elliot, and there's no point in you or me reinventing the wheel on this one. To make your own crossover to install at the right place inside your own amp (if your amp has a "tape loop" in and out, you can just use that), go to his website at this page (there's more than this page, but this is a good place to start):
(the link to his home page, because he has a ton more stuff than just the crossover, is in the list of favorite links on the right side of this page near the top)
Tubes only do one thing really well: they voltage-amplify an audio signal and add a "tone" or "character" to the sound that really pleases the ear. There are lots of theories as to why tubes make audio sound better, but the fact is we really don't know why tubes make audio sound better - we just know they do.
Now, mind you, something that might surprise you: Probably the most linear device in all of electronics is a (properly set up) Triode. Not a pentode, not a beam former (modified tetrode), not a mosfet...and for Heaven's sake certainly not a transistor!!! And, even when a triode is a bit over-loaded (they often are), they usually generate mostly just 2nd harmonic distortion, which our ears like just fine (nature is FULL of 2nd harmonics. As Nelson Pass...or Lynn Olson...(heck, I can't find the reference right now) pointed out, any sound in nature is comprised of pushing air and then pulling air - and since air pushes more quickly than it can be pulled, 2nd harmonic generation from any vibrating source - whether it be a hound-dog howling, a cricket chirping, the wind rushing through oak trees, or a violin playing Beethoven - is going to be the dominant pattern of distortion, so we are neurally adapted to not only not mind some 2nd harmonic, we probably think it makes sound more "natural". But, the fact remains that a properly set up triode is very, very linear, with only a tiny amount of distortion, and the tiny amount there is, is 2nd harmonic. So, an extremely well set up triode amp, even without any negative feedback at all, is capable of vanishingly low distortion! (Just so long as you don't need tons of power, another subject for another day...)
Now, Nelson Pass has recently made the statement that 3rd harmonic seems to be preferred by most people in a push-pull output circuit, over 2nd harmonic....but I'll have to write a separate article, after I do some testing, on THAT idea. He may have a point, though: the Heathkit AA-151 is a push-pull output EL-84 tube amp, and it DOES have higher 3rd harmonic than 2nd...and it DOES have a "sweet" sound...but I think something is going on between the interplay of 3rd harmonic from the amp and 2nd harmonic from the speakers where the final "waterfall" pattern is actually restored...but let's move on for now with the present argument, I'll figure out what's really going on in this 3rd vs. 2nd harmonic debate in another blog:
So, how come op amps and transistor amps have such low distortion, like ridiculous numbers like 0.001%, which seems, like, PERFECT? By using TONS and TONS of corrective negative feedback, that's how come. Which some audiophiles believe loses musical content. I'm not COMPLETELY sure about that, but I think it's certainly at least partly true...there are subtle nuances to sound that we are far from understanding yet, and if a signal is terribly distorted by the non-linearities of transistors and then the output is FORCED back into a low distortion copy (but amplified) of the original signal, it's hard to imagine that some of those subtle nuances, many of them probably down in the "noise" floor, some of them extremely brief but actually of very high amplitude, are not lost.
There is another consideration with global Negative Feedback that was missed for decades. If the amp has any coupling capacitors in it...that is, capacitors directly in the signal path...then the phenomenon of "blocking" can become a serious problem...and global Negative Feedback (gNFB) makes the Blocking far worse.This is important. What is blocking? That's when a sudden loud transient (drum, cymbal, etc.) or rapid crescendo momentarily drives the next stage into cut-off, or clipping (usually the output stage), and the coupling capacitor gets "unbiased", so to speak. A coupling capacitor driving a stage has to be biased somewhere near the "midpoint" of the stage it is driving, so the stage can swing both "up" and "down" without hitting the ceiling or the floor. The capacitor swings up and down first, and the next stage follows this swing. For the capacitor to be able to swing up and down within the range of the next stage - that is, swing up and down between ceiling and floor without hitting either - it has to be "biased" at a voltage that is near the midpoint - about halfway between ceiling and floor.
If the "far" side of the capacitor has this huge charge on it momentarily that hasn't drained off - so the bias - midpoint charge - can be restored - and a new audio signal peak hits the "near" side of the capacitor...what happens? Nothing. The capacitor, because the next stage it is connected to is still stuck to the ceiling or the floor, "blocks" the signal. The amplifier loses sound for a moment, and as the sound comes back, as bias (midpoint) is restored to the capacitor and following stage, it comes back extremely distorted. It sounds awful.
Here's why: in our analogy, we've got the next stage stuck to the ceiling or the floor. As bias is restored, as the capacitor floats back to the midpoint between the ceiling and floor, and sound starts to pass through the stage again, what happens to the WHOLE sound, the swing both up and down? One side or the other gets cut off. If the stage was stuck to the ceiling, the half of the signal that went UP is cut off. If it was stuck to the floor, the half of the signal that swung DOWN is cut off. As bias - midpoint - is restored, then more and more of the entire up and down swing of the signal is restored, and the sound gets less and less distorted.
Ever hear of a Fuzz-Box for an electric guitar? Basically, that's what is happening in the effects pedal - part of the signal, either the UP swing or the DOWN swing (or both) - is getting cut-off. Might sound great for a Heavy Metal Rock Band - and it did sound great when The Ventures used it in 1961 (2000 Pound Bee), and then Dave Davies of The Kinks imitated it by cutting razor-blade slashes in his speaker cone, and especially when Keith Richards of The Rolling Stones used a Gibson Fuzz-Box for "(I Can't Get No) Satisfaction" (referenced from wikipedia: http://en.wikipedia.org/wiki/Fuzzbox) -
...but Beethoven through a Fuzz-Box? Miles Davis through a Fuzz-Box? Maria Callas? Deborah Voigt?....
...or, to carry a joke too far...
...Ruben Studdard or Jordin Sparks through a Fuzz-Box? Well, maybe Studdard or Sparks (or Taylor Hicks - that might work!!!)... (just kidding) (I actually really LIKE Taylor Hicks. The rest I could live happily without....)
Now, the bias on the capacitor will be restored fairly quickly, but that "hiccup followed by a burp" in the sound of the amp still ruined a musical moment. Here's where gNFB comes back as a little devil.
Remember that gNFB forces the amp to have the same output as the input, except for amplification. Some of the output signal from the output transformer is fed back to an input stage inversely, so that any deviation from the input - at the output - is fed back from the output - to the input - as a correction. Sounds like a great idea, huh? It's how amp manufacturers, whether transistor or tube, were able to get those 0.001% THD numbers. But, here's the rub: if a high amplitude transient (sudden loud sound) goes through the amp and hits the output stage and clips the amp, the gNFB will send it back to the input stage inversely in an attempt to "unclip" the output...which can't be done!!!!! Explanation: The output is already clipped...and now the gNFB is trying to make it go louder...so it just clips longer...
So, what was before a tiny moment of Blocking now becomes this long, distorted, ugly string of moments as the amp is sent into clipping oscillation...the input is trying to correct the output clipping because of the gNFB telling it to, which just clips the output more, and then the gNFB tells the input to correct THAT, and, as you can see, the cycle repeats itself over and over until it eventually dies out from internal losses in the amp. Worst case: the amp goes into a loud, buzzing oscillation and doesn't stop until you turn it off. This usually doesn't happen, because the frequency range of the amp will be limited in order to prevent this. Usual case: a spoiled moment of crescendo where all the clarity is lost. You hear something loud, but it doesn't sound good - there's a mudiness, or background buzzing or crackling, or even a loss of sound followed by fuzziness. The first time I heard this, I thought it was my needle mistracking in the vinyl groove...until I turned down the amp volume and realized it was the amp, not the turntable cartridge.
By the way, the loud transient that causes the blocking doesn't have to be in the audio range! It can be a Radio Frequency transient that made it through the amp...the needle of the turntable hitting a piece of dust, the CD player losing timing for an instant and misreading the digital code, a burst of RF interference from some idiot with an illegally over-powered CB transmitter...so amps that have specs where the treble goes to 500 KHz or some such crazy number may not be so good after all. The old Heathkit AA-151 only had flat response in the treble to 15 KHz, above which it fell off steadily, and you know what? It's a sweet, sweet sounding amp. I think the total bandwidth was only to about 150 KHz max, which is plenty for an audio amp. So, once again, numbers in audio amps can not only be misleading, they can mislead you to much worse sound for more money.
Note: Max's design at AngelFire (see links, near top) for the EL-34 PP power amp is a notable, and educational, exception to this topic of "blocking". It turns out, that if the output stage has tons of reserve capability, blocking ceases to be much - or any - of an issue - because the output stage is NOT being pushed to it's limits. Isn't that cool? So, what this means is that direct coupling to an output stage is not necessarily the only way to avoid "blocking" - you can capacitor-couple if you design the output stage so it's "breathing easy", even with high power transients. Cool, huh? What would probably be the best of both worlds? Direct coupling, of course, driving the output stage with cathode followers or mosfet followers or tubelab's powerdriver circuit (see links for tubelab) AND "over-tubing" the output stage so it doesn't get pushed to the limits. But....if the output stage is over-designed so it doesn't get whacked up to the ceiling or smacked down to the floor....is it worth the extra complexity of direct-coupling? Hard to say. Your choice. Capacitor coupling is certainly easier, cheaper, and safer. Safer is good. Look carefully at Max's design. Remember that many of the problems we have to deal with in DIY amp design are the result of CHEAP design decisions by manufacturers trying to make enough profit to stay alive...some of these problems are "straw men"....they only exist because of costs, they are easy to eliminate once we get into the mindset of being a DIY'er, not a manufacturer. "Blocking" is a great example. Over-design the output stage and suddenly...."blocking" is not such a big deal.
Of course, it is a truism - a generally true truism, for once - that the main problem with SS amps is the harsh clipping (and almost ALL amps clip, don't kid yourself about that...even if it's just extremely brief, high amplitude transients that we sense more than hear....tubes just play nicer when it comes to clipping.)
But, in the end, despite all my fancy arguing, generations of audiophiles and musicians have simply learned through experience that a decent tube amp always sounds a lot better than a solid state amp (assuming they can hear the difference, of course...see my article "Listen Up!"). Are there some exceptions in the solid state amp world? Yes. Can I afford any of them? No. So, give a good but short-on-money guitarist the choice of a tube amp or a transistor amp - assuming he or she has just enough for the tube amp or a relative is going to buy it for him or her - which will he or she choose? The tube amp. They're no dummy. Why? That's a subject for a whole new article, which I will eventually get to.
We know some bits and pieces, yes...at the risk of repeating myself, but with a little more detail...we know that almost all amps always clip (we'll make an amp that's an exception, but the fact is that most amps clip)...and that when tubes clip they sound much nicer than solid state, which clips harshly. We know that tubes - used properly, that is - tend to have a "waterfall" distortion pattern where the second harmonic dominates, and distortion falls off quickly and usually doesn't go appreciably above fifth harmonic - and that this imitates nature, so our ears like it. Solid state amps generate odd numbered harmonics that go far higher...three, five, ten, twenty, a hundred, a thousandth harmonic above the fundamental...and our ears do NOT like these odd harmonics. (Some say we can't hear these higher odd harmonics. I think we can "sense" them - and Lynn Olson says he believes they mix with lower frequencies to create ugly artifacts in the sound we certainly can hear). But there's more to it. A tube - used properly - gives a sound that is warm and pleasing...but has a "bite" to it at the same time...with sound-stage width, height and depth...clarity....unbelievable realism for voice and mid-range instruments...and a satisfying quality. That's the crux of it, right there: we can use a million adjectives, but a good tube amp satisfies. A solid state amp may have power, clarity, frequency response, ridiculously low noise, ridiculously low distortion, but, in the end, it doesn't satisfy - there's something missing!! (a tube... :)
So at least one tube in an amp is absolutely necessary....if the sound of tubes (actually, the combination of great linearity - low distortion without resorting to huge amounts of gNFB - and the "waterfall" distortion pattern characteristic of triodes, anyway, dominated by second harmonic (but way down near the noise floor), then less 3rd, less 4th, etc.) matters to you.
Usually, there need to be a bunch of them. But there are a lot of things that have to be done in an amp that are NOT best done by tubes - that are not directly involved in voltage amplifying the audio signal and adding a pleasing "character" to it - and there is no reason to use tubes to do these other tasks. Using tubes to produce output power, or filter and regulate B+, or supply filament current, or convert voltage to current, or equalize frequencies, adds unnecessary noise, is expensive in money and space, and wastes tons of energy.
We do need to start being thoughtful about wasting energy...so we use a few tubes in an amp to get beautiful sound, and we do everything else with solid state to conserve energy and get the job done efficiently and accurately.
So, in this site, I'll be showing how to use solid state to give tubes the support they need to work superbly.
In this site, we'll build a superb filament supply using solid state that will make your tubes last far longer and at the same time eliminate hum and noise.
We'll make a filtered, regulated B+ supply that's stone-quiet, supplies gobs of power, and does not color the sound of the tubes.
I'll be showing how to do tone shaping and equalization using solid state components for far more accurate results that can be achieved with a tube, more cheaply, with a lot less energy usage (heating up filaments in extra tubes in extra tone stages wastes a lot of energy).
I'll also be showing how to faithfully take the sound of an output tube and translate that into output power using mosfets, instead of transformers, eliminating the coloration and distortion of transformers. This, by the way, is the exception to the rule for bi-amping tube amps. If the conversion of voltage to current is done by using a mosfet output instead of a transformer, then you CAN have all the bass you want. But, except for certain speakers (Klipsch Horns certainly come to mind), even with a hybrid tube/mosfet amp, bi-amping and sending the bass to separate subwoofers is STILL the best way to go. Otherwise you just have to do the crossover in the speaker cabinet instead, and it's much better done inside the amp in the first place.
If you like the idea of playing with mosfets, this site may revolutionize the entire idea of tube amps for you. If not, please feel free to go to sites using output transformers - there are certainly a bunch of great ones, and I'll list them on the right-hand side.
We'll actually be doing each part of an audio system ourselves, except the turntable cartridge...that's beyond even DIY'ers unless you have a really good open-stage microscope! I don't, at least not yet, so cartridges will have to wait - although a DIY Decca type cartridge is a dream of mine. Maybe someday. But we will do our own air-float radial-track tonearm...you can make it yourself from my kit, and it will blow away every tonearm in the world (OK, a little over-exaggerated there...let's just say pretty darned good for small money).
But we will start with amps, a piece at a time.
Some of the projects that will be posted here:
An auto-grid-bias board, complete with PCB and kit, if you want them, that allows you to keep an output push-pull pair in perfect balance, no matter the kind of amp or tubes used. It can also be used to control the grid bias on all the tubes in all the stages of the amp. It comes with built-in protection circuits that prevent tube-runaway if, for example, the amp should lose it's negative supply - normally a disaster in grid-biased amps, but not with this board....no worries...or if the output is dead shorted - again, normally a disaster, but not with this board.
I call this the Broskie/Knouse Auto-Grid-Bias board, because the central idea of the circuit - using an op amp in integrator mode to control the bias to the grid - was John Broskie's original brilliant idea. This circuit is my own implementation of his original idea. When I get the PCB's done and can send him a couple of finished ones, I'll ask his permission to include his name officially and even see if he would like to sell the kit through his site (tubecad - one of the best, if not the best, tube blogs on the planet - if you don't know it, go there now and read it all (it'll only take a few months)). Here's the main link:
An all 6BQ6GTB amp - an all tube amp using one of the cheapest of all old tubes, an old TV tube (horizontal deflector), that will sound as good as a $10,000 amp (well, close enough, anyway ) - with a total of ten bucks in the tubes. The beauty of this amp is you only need ONE tube type...you don't have to worry about five different types of tubes, and which one is going to get rare. All tubes will eventually get rare, I mean the old ones made in the 30's, 40's and 50's, but I can assure you the 6BQ6GTB will be among the very, very last to go...probably well beyond your kid's lifetime, so don't worry about it. Now, amps using the 6BQ6GTB have already been done, and brilliantly - here's the very best example I know of:
by a truly brilliant electrical engineer who goes by the username Miles. If you don't mind using different tubes, by all means build his design. My design, for the fun of it, will use ONLY 6BQ6GTB's in all the stages - and it will also have a special feature Miles' amp doesn't, which is a "tone shaper" that allows you to modulate the "tone" of the amp from pentode to UL to triode Single Ended - but the really nice thing is that it will use only one tube type, and that tube type is A: dirt cheap, B: performs great, and C: was made in train-car loads for TV's that were never built - so it should be around a long, long, long time. (And nobody besides me and Miles and a few other crazies want them, so that's your good luck). And, unlike Miles' design - which, again, is superb, if you like output iron - in mine the output voltage-to-current transformation will be handled by mosfets, not output iron. So not only will this amp have ridiculously cheap tubes, a big chunk of expense - the OPT - will be cut down to pennies on the dollar.
An 813 amp capable of a thousand watts per channel. Hint: no output transformer. But not tube to speaker direct, that's really a non-starter, even though people persist in trying to make OTL amps work. Oh, it can be done, but not well. No, a truly different output stage - mosfet - that transforms the high voltage of the 813 to incredibly high current for speakers without a transformer. This will be one where you do NOT turn the volume up very much - all that power is for headroom for transients, NOT for continuous output - unless you happen to have speakers than can handle it. So, if you use this amp and turn the volume up to stadium-filling levels, you'd better have the right speakers, or you're going to burn your house down when your speakers explode into towers of flame. I'm not kidding.
How to mod an old Heathkit AA-151 from top to bottom - truly outrageous modding - taking an old, sweet-sounding integrated tube amp that includes a phono preamp, fixing all it's flaws, modding it to take easily obtained tubes (since some of the tubes in it are now rare and expensive and getting rarer by the day), and making it the heart of an outrageously expensive sounding system with magnificent bass - but it's still just an old tube amp you can pick up fairly cheap on ebay.
How to do the same thing to the old Heathkit AA-100.
A DIY air-floating radial tone-arm...transform just about any old, used turntable into one of the best in the world, and do it all yourself for pennies.
How to make a bench power supply that allows you to do just about ANYTHING on the bench - a real help when prototyping and testing circuits. There is not a bench power supply on ebay that comes close, and the old tube ones are not worth the money - you have to rebuild them completely to have anything worthwhile, and you still don't have all the supply you need to make prototypes of hybrid tube/SS amps - and new commercial supplies are not only incredibly expensive, none of them are truly set up with the DIY'ers making tube/SS hybrids in mind - so you might just as well build this one.
How to use synchronized mosfet fullwave bridges to transform AC filament supplies in old amps into DC supplies, without losing voltage and at the same time control the turn-on surge to protect filaments. Now, this is some serious SS fun. This makes using diodes look like trying to use stone axes to build a house.
A nice, simple, powerful pedal steel amp. Not a guitar amp, not a bass amp, a real pedal steel amp. For those very few special musicians in the world who can actually play one...
Yes, a first-class guitar amp capable of amazing tones, for home play and small-venue gigging. (But this will be AFTER I build Guido's guitar amp and then figure out how to tweak the design to my own version (mosfet output; distortion in the tubes driving the mosfets)....if you want to build a guitar amp, don't wait for me (it's gonna be a while), build Guido's...or maybe you can offer him enough money to build one for you. ). The link to his website is in the list of favorite links on the right side of this page; just look for Guido's Site.
Eventually, a personal, highly portable FM receiver you can carry in your pocket and pull in that weak classical station you can barely get and listen with great pleasure. It will have to have a digital option eventually, also, since digital radio is inevitable, but we'll start with analog, since analog will still be with us...thank goodness. (I'm actually counting on this super-nice FM geek in Denmark, Mikkel, to create the receiver board part...see his very cool website and great projects with PCB's, (he is a MASTER PCB designer), he's listed in the favorite links to the right ...there are two of them, Mikkel's Tube Site, and Mikkel's Projects Site)
Please note this blog will also be separated into categories, such as: Great Sites for Tube Audio (with some reservations, of course), Rules for Joining Tube Forums and Avoid Becoming Unwelcome (or How to Get Help Without Getting Beaten Up), Twenty Rules for Tube Audio, Things That Really Are Baloney (and You Shouldn't Waste Your Money On), Filament Supplies, Power Supplies for B+, The Biggest Differences Between Guitar Amp and Real Hi Fi Amps), and so on. You may note I'm not a great fan of forums. I've belonged to a bunch of them, and they have gems of info - but you have to know how to wade through all the bullshit, and you post at peril...there are a lot of sharks that just love to cut down any idea they didn't come up with themselves. You're probably best off "lurking and learning". But more on that later.
When I figure out how to do it, I will be asking for comments, improvements, errors if you see something - not a free-for-all forum, but if you have something helpful to say I'll post it along with attribution to you, with thanks. This site will not have a forum, it will have a "soiree" - where ideas can be shared safely, where truly original thoughts are welcome - but where "shouters on soap-boxes" and "old crabs" can't get through the door. If you're new to tube forums, I'll give you a few suggestions:
funwithtubes at yahoo...the email forum is on yahoo, the home site for
the email forum is at http://www.angelfire.com/electronic/funwithtubes/
Max keeps the peace on the forum, and the forum really does have a nice
feeling and tone to it, and his home site (above) has great info and
some great project amps on it. You would do well to just start at his
site and build his designs.
http://geek.scorpiorising.ca/GeeK_ZonE/ (although be cautious; read my Rules for Joining a Forum and Avoid Becoming Unwelcome before going here - for starters, just lurk, really try to avoid the impulse to jump in with a stupid question - in general, it's got super members and some real experts (Miles, Yves, Tom, Gregg, etc.). You're best off simply finding a project by a member you like and building it.
Very useful links for many of the old-time members of GeeK_ZonE above - all of these guys really, really know some stuff about tube amps: http://geek.scorpiorising.ca/links.html
And, last but not least, http://www.tubecad.com/ where you'll find the smartest audio articles ever written, by Platinum Brain Award Winner John Broskie, and some of the best amp kits available (PCB kits; you still have to make the box, install the controls, etc....but that's half the fun!) Here's the link for his yahoo store, where you can buy the PCB's or the full kits - like TubeLab.com, these are kits where you just can't go wrong, they are superb: http://glass-ware.stores.yahoo.net/
By the way, if I have accidentally left out a worthy forum or DIY site, please feel free to show me the error of my ways and I'll take a look at including it here (once I figure out how to make the "contact me" thingie work...).
So why am I bothering with this site? Between AngelFire.com and GeeK_ZonE amd ClassicValve.ca and tubelab.com and tubecad.com, what more could you need?
Because I bring a different, slightly eccentric view to things, and if you want a source in addition to those listed above for amp designs, here's a good place to find one (when I get them up!). And, if you have an old Heathkit -151 (and eventually AA-100's), here's the place to make it brand spanking new, a truly fabulous modern amp in a sixty year old chassis (when I have time to get all that up also!).
Best Regards,
Charlie Transformation Audio
P.S.: a few more links to cool sites, some of them small, odd, but with great tips (I'll eventually organize this into a category of recommended sites):
http://www.geofex.com/tektips.htm (for various tips on prototyping; written for stomp box builders (guitar effects) but very helpful to tube amp prototypers and other purposes as well, although I see he's given up on the link for how to use a laser printer to make your own pcb's...I guess you either have to set up your own UV system for photo-sensitive coated copper, or use one of the commercial pcb makers...boards are now so cheap and the free software so powerful, including silk-screening labels and solder mask and tinning of the copper, that it hardly seems worthwhile to make your own by hand anymore. If anyone disagrees with this, and has a proven method for making your own (complicated) PCB's for much cheaper (without buying super expensive software) please let me know!! I'll definitely post any such link!!)
http://www.geofex.com/Article_Folders/mosfet_folly/mosfetfolly.htm A timeless page that I hope never disappears from the web, containing essential information for understanding how to use mosfets appropriately in a tube amp...and why. You might want to print this one out, since if it disappears I don't know any other sources for it. I'd gladly copy it here, if I had permission. Perhaps I'll try to contact the author and see if he would like to have it posted, with attribution to him, of course, in other places, so it stands less of a chance of ever dying from the web.
http://www.vt4c.com/shop/program/main.php?group_id=2 For the adventurous, here's a link to a place in Hong-Kong that sells simply amazing parts for making amps. I have been told that yes, you wire your money, and yes, your stuff eventually shows up, against all odds and expectations...although I haven't tested it for myself yet. On the other hand, I have purchased test equipment from other companies in Hong Kong, wiring the money in advance, and I have to say it showed up, every time. Just make sure you follow their directions carefully; when the wired money shows up, they don't know who it came from or what is ordered or where to ship until you send an email that allows them to hook the two things together. Or use paypal. I'm not such a paypal fan, but if it works for you, go for it. The nice thing about paypal and Hong Kong is paypal automatically forwards the information along with the payment, so you don't have some poor Hèung Góng Yà hn guys scratching their heads and wondering what you paid for and where to send it.
A Brother Eagle Story,
Charles Knouse, Copyright 1994, 2008; originally created and told to 2nd and 3rd graders at River Valley Elementary School in Athens, OH. (This is not the first story in the sequence, it's just the first I've managed to get written down......it's also the written version - if you like it, you have your choice of telling it yourself or reading it - and, as you'll see, you even have a choice about plot near the end...)
Once upon a time, in a land very far away, and in a time very long ago, Andrew, Max, Hannah and Cameron, and their special friend, Brother Eagle, were playing in the back yard of their home, the tallest castle in all the land.
It was a late summer's day, beautifully gusty, with a high sky and billowing clouds racing and perpetually building even larger castles against a brilliant blue, and the sound of oak leaves chorusing how very grand a day it was.
A day to be alive, to feel one's vitality and hopes bursting from one's chest, too big to be completely contained. A day of darting and chasing and tackling and tickling and laughing oneself silly in the streaming light and racing shadows. A day that held just a hint of Autumn soon to come, that would see the fall of those same leaves now roaring with pleasure.
There was a fence at the very back of the yard, a very nice, low, white fence that had no real outward purpose, since there were no very large beasts of prey in the woods behind, but it had been put there, nonetheless, as a token of grace, a sort of half-formed thought that childhood, even as safe and joyous a childhood as was played in that yard, should have a safe margin, like a simple, pretty, unobtrusive frame round a painting of vivid color and bounding action.
Today, however, Brother Eagle had left the childrens' game and was perched on the fence, gazing far into the distance at the mountain across the valley. Something about the mountain had caught the corner of his eye while snatching the bonnet off Hannah's golden head and whirling it to Cameron with a flick of his talons and a scream of laughter, this distant mountain, because he saw something he had never seen before but recognized instantly from old stories from very old owls he had known as a child himself.
Brother Eagle was no longer a child, but he was the children's best friend, playmate and often ill-informed advisor, though certainly well-intentioned, unknown to the children's parents, but known to all the animals and plants for miles around.
What he had seen made him feel desperately worried. He was worried for his old friend, before the owls, even; his dear friend the Old Pine Tree.
For Brother Eagle had seen the top of the mountain - lift off. Blown right up into the air.
The sound of the mountain-top lifting off had not quite reached them yet, it was so far away, but there was now a flash of yellow-orange where the top had been - and above it a black, towering mushroom-shaped mass that had been blown into the distant sky - and so Brother Eagle shouted to the children, never taking his eyes from the mountain, "cover your ears! The sound is coming!"
They just had time to clap their hands to their ears and turn toward Brother Eagle with startled eyes before the great wall of thunder slammed into them. The long roar of faraway bursting boulders and bellowing furnaces rolled over them, leaving them sprawled on the gound.
They crept up to Brother Eagle, Andrew first, as the biggest, Hannah second, as the fiercest, and Max and Cameron together just behind, Max having instinctively grabbed Cam - for they called him Cam for short, although he was starting to shoot up, catching up to as tall as they were - as the most cautious, though equally game for anything. Cameron and Max were far more delighted than frightened, however, a delighted grin growing across both their faces and their mouths forming un-hearable, above the din, exclamations such as "Wow!' and "Sick!" and "Massive" and - and here Hannah shushed them (no one could hear each other, but she could lip-read, as well as talk sign-language), for she had seen the expression on Brother Eagle's face.
He was very distressed, the most upset they had ever seen him. Tears were being whipped away by the continuing wind, and each blink would release a fresh spray. His beak was open and motionless, as if his mind was struggling to overcome some monstrous horror and begin to know what to do.
Andrew asked him, gently, though he had to shout very loud, what was wrong, and Brother Eagle only shook his head. It was impossible, this thought that was forming, but he didn't know any other way.
He was on the verge of giving up, of finding a way to hide his secret so the children would not be drawn into his terrible knowledge, when the look on Hannah's face and the dying down of the wind gave him the permission he needed to ask for help from his friends.
Staring at the fire from the distant volcano, Brother Eagle said, "It's the Old Pine Tree." He paused, he didn't know how to go on.
All four of the children saw the wretched look on his face and instinctively, with sinking hearts, they all turned and looked at the molten lava gouting from the top of the volcano. As they imagined they could feel the heat despite the distance, they saw what Brother Eagle had seen: the fire starting to creep down the sides of the mountain, engulfing every animal, plant and wood in its path.
Max, the one whose middle name might have been Justice if it had not already been Christopher, said to Brother Eagle, "We must save him!" Now, let us pause here and ask ourselves, dear reader, "How did Max know The Old Pine Tree was a male?" Indeed, do trees come in male and female? I do not know, and I am sure none of our five heroes knew, this might be something for you to look up for yourself, but they did know The Old Pine Tree was somehow an old man, and that he was about to be burned to ashes.
One of the many, many reasons the four children loved Brother Eagle was that he was always, always game for whatever adventure they might present - except, of course, as we all know, when he was too frightened and tried to hide under one of their beds - but the children always found him and dragged him along, so in fact he had never actually been absent for a single escapade. And Brother Eagle was certainly not going to be absent from this one, not when it involved his first and dearest friend, The Old Pine Tree.
So Brother Eagle told them to jump on his back. "Bury yourselves in my feathers," he warned the children, "so the sparks don't get you", and they did, gladly, as the hot, ashy air threatened to burn their hair and scorch their skin. Off they flew, from the bright backyard into a deepening gloom of smoke and burning embers. Brother Eagle had no trouble taking off, for that year the children were still quite small and did not weigh much at all.
"Brother Eagle," said Cameron, "you smell of old dusters and bed-quilts!" "Cameron!" cried Hannah, "he does not, he smells lovely, like honey and cloves and pumpkin!" "Huh?" answered Cameron, "what land do you live in? You've been riding in too many coaches made of pumpkin and drawn by mice!" which was not very nice and earned him a sound punch on his arm from his sister. He would have punched her back but just then a gust of particularly fiery wind made all of them hang on as tightly as ever they could, for fear of being swept away into the burning darkness.
When, at last, Andrew had begun to wonder if it was ever going to end and how Brother Eagle could possibly fly another stroke, Brother Eagle made the nicest landing, against cross-gusts and sparkly-whirlwinds, to the very top of the tallest, oldest pine tree they had ever seen.
As the children carefully climbed off Brother Eagle's back onto the top branches, holding tightly, Cameron nonetheless managed to give Hannah a return punch, saying, "there!" as he did so, and then giving a short shriek as he almost fell. It was a good thing Cameron was such a superb athlete and could get in a punch just not too hard whilst turning a somersault in mid-air and finding a grip with the other hand on the very tip of a perilously small branch.
He would someday invent karate, jai-alai and, later, baseball, and these inventions would find their way east, west and west again through the Mongol-oppressed Chinese, the Mayas and an American named Doubleday, or Cartwright, depending on which version of history you believe, but that's getting far ahead of our story. It was also the reason Hannah also punched him not too hard, that along with the fact that she loved him so dearly, but that's also a different story; this is a story of a sort of Christmas in a land long before Christmas, and of trying to save an old tree from a fiery death.
"Old Pine Tree", Brother Eagle whispered, "I would like you to meet my friends. These are Andrew, Max, Hannah and Cameron." Then he brought his head close to where the four children's heads were huddled together near the trunk, out of the hot wind's blast, and said, "Children, I would like you to meet my oldest, dearest friend, The Old Pine Tree."
Now, the children looked at each other in a little bit of surprise, never having tried to speak to a plant of any sort before, much less a tree, but with Andrew leading they all gamely said, in their politest voice, "Hullo, Mr. Old Pine Tree, we are very glad to meet you", and then they waited, not sure what would happen next.
What happened next was a brief lull in the wind, as if the wind were listening too and knew the Old Pine Tree wished to speak, followed by a shivering that ran all through the old pine's needles and twigs, a shiver that whispered to them in the briefly still air:
"Hello, children. I am very glad to meet you, too."
Max laughed, as he sometimes did for no reason anyone could figure out, and Hannah shushed him, as she often did for obvious reasons, but then Max's face grew solemn and he said, "Mr. Old Pine Tree, Brother Eagle tells us you are his oldest friend, so we are here to save you." The Old Pine Tree replied, in his whispery, shivery way, "Thank you. I would like that very much." Then Cameron blurted, "Are you afraid?" and the Old Pine Tree said, "I have been through many a fire, but this time the fire is from lava, so, yes, my little friend, I am very afraid." Hannah said, "I am sorry this is happening, and we're going to get you out of here!" at which the Old Pine Tree laughed gently, his branches swaying slightly, and he said, "I wish you could."
Then Brother Eagle broke in and practically shouted, "Yes, my old friend, we will save you!" but then he stopped.
For how were they to save the Old Pine Tree? As the wind blew again they all huddled against the Old Pine Tree's trunk, deep within his branches, and talked about it. Andrew said, "He's awfully big. I don't think we can dig him up." Max said, "Well, let's find out. Old Pine, how about if we dug you up and rolled you down the mountain?" Max had thought up the part about rolling Old Pine down the mountain by himself, he was very proud of it. But the Old Pine Tree laughed again, and said, "Thank you so much, my brilliant young friends, but I could never leave. My roots are too deep, I would die if you cut them." Max shouted back, "But you're going to die if you stay here!" and the Old Pine Tree replied, "Yes, I'm sorry to be such a difficult old man, but there's no help for it."
Then Andrew spoke up and said, "Well, if we can't move you, we will have to figure out how to protect you," and everyone agreed with Andrew, and started popping ideas about just how to do that.
Now here, gentle reader, is the place where, if I were telling this story to children, as I have done many, many times, I would warn them that although there was absolutely nothing Brother Eagle or the children could do to save The Old Pine Tree, I was happy to try out any ideas they might have.
Children being the same, no matter the time or place or race or nation, they would come up with idea after idea, and no matter how many failed, they would come up with still more, convinced that there surely must always be a way.
You and I, much older and wiser, of course, know better, which is a very sad thing, and one of the great tragedies of life…for without hope, nothing can be done, and yet sometimes nothing, indeed, can be done. However, children have to learn this for themselves, sooner or later, I suppose…and I do wish this story had a magical way out for our new friend the Old Pine Tree, but against a volcano, what can be done?
Still, I always, always let them have their say, and we try every single idea - or at least all the ideas we can until it is obvious that if I don't start wrapping things up the bell would ring before I finished, and that would never do.
Perhaps it would be better to tell the children listening that there are two endings, and they can hear them both: the one where Brother Eagle and the children magically save the Old Pine Tree, and the other where they - don't.
I think I will try that next time, and you, dear reader, are certainly welcome to try it out yourself, but in this story I hadn't thought of that yet, so in this story, they - don't.
Nonetheless, they tried their very best, which is all anyone can do.
So, the children carried buckets of water to try to put out the volcano, and that didn't work. And then they strung hoses all the way from the castle to the top of the volcano, even though garden-hoses would not be invented for another thousand years, but all that did was drain the fish-pond dry. And then a bright little girl suggested fire extinguishers, invented even later than garden-hoses, but those, of course, failed too; it's not easy to put out a volcano, as the people of Pompeii found out the hard way. As the helicopters and B-52 bombers dropping train-loads of water and fire retardant also failed to stop the volcano. And then, inevitably, the idea of the fire ditch came up, and the lava simply filled it to overflowing and ran down the mountain straight for our old friend. And then there was the concrete wall, replaced by the steel wall, replaced by the wall made of un-meltable diamond, replaced by the wall of un-crackable platinum-diamond alloy, but they all melted, or cracked, or crumbled, or were submerged under the onslaught of the molten rock.
And so it comes to pass that the room grows silent, the children begin to understand that this story really is a bummer, that Disney is not the arbiter of all reality, and the realization grows that the Old Pine Tree is going to burn up. Surprisingly, I've never had a child cry or yell at me at this point; I'm not sure why, you would think they would be furious with me, but no, they start to think hard about what I'm really about, notice that the hour is almost up and I'm going to be in trouble if I don't wrap things up soon, and so settle down to wait me out.
Part of the reason acceptance finally comes at this point, too, I think, is that, in the end, children are pragmatical creatures at heart, and as much as they love fantasy, even if they're the one dying, they're willing to let go; I think perhaps they understand death better than we grownups do.
And so we find our five heroes huddled again against the Old Pine Tree's trunk, exhausted, crying, defeated, shielding themselves as best they can from the savage heat of the lava that was oh, so close now.
Brother Eagle asked miserably, "what do we do?" and before Andrew or Max or Hannah or Cameron could think of an answer, the Old Pine Tree said to them, shivering his very bark, "You must leave, my friends."
"No!" shouted Max, "we won't leave!"
"Yes!" agreed Andrew, "there must be a way!"
"Old Pine Tree" pleaded Hannah and Cameron together, "tell us what to do!"
And the Old Pine Tree whispered to them, "there is nothing more you can do. I thank you with all my heart, you have been the best and truest friends a person could ever have, and you have fought for me most bravely and brilliantly. But there comes a time when you have to say good-bye; it would hurt me terribly to know I was the cause of harm to you, so please leave now while you still can."
Since he asked so nicely there was nothing they could do but agree, so Brother Eagle climbed to the top and said his goodbyes, telling the Old Pine Tree how much he loved him, which is all anyone can do in the end, really, and then the children climbed up onto Brother Eagle's back and, one by one, also said goodbye.
"Goodbye, Old Pine Tree" said Andrew.
"Goodbye, Old Pine Tree" said Max.
"Goodbye, Old Pine Tree" said Hannah.
"Goodbye, Old Pine" said Cameron.
"Goodbye, Andrew, Max, Hannah, and Cameron", said the Old Pine Tree, "it was very nice to meet you," shivering his needles with the most courtly elegance imaginable.
"Very nice to meet you, too," chorused the children, shivering their own hands as they spoke, unknowingly imitating the Old Pine Tree.
"Goodbye, my dearest friend Little Eagle," whispered the Old Pine Tree with a break of grief in his shivering voice, and Brother Eagle sobbed back, "Goodbye, old friend, I love you."
"I love you too," shook the Old Pine Tree from his roots to his top in a low thunder, and at that, Brother Eagle tried to take off.
But he couldn't take off; the wind was too strong, they would all have been blown right to the ground and dashed to pieces. So Brother Eagle asked the Old Pine Tree to help, for Brother Eagle was now very afraid for the children, and the Old Pine Tree cried out with all his parts, "Sister Wind, Sister Wind, please be kind enough to allow Brother Eagle to take wing," and because Sister Wind had heard the whole thing, as she hears everything, she called to all her sisters on the mountain-side and they all, for a moment, paused, holding back the mountain's fire.
In that moment Brother Eagle sprang into the sky, shouting "Goodbye" for the last time - for as soon as the word was out of his beak, all the Sister Winds released the mountain's fury and hurled our heroes in one searing blast from the side of the volcano all the way across the sky to a little bit beyond the backyard fence, where Sister Wind dropped them gently onto the soft, warm grass, Brother Eagle's precious burdens intact.
The children spent the rest of the afternoon consoling Brother Eagle, holding his talons and his wings, Hannah stroking his back and telling him everything would be all right, and they saw streaming out of the burning forest and swimming across the steaming river every mammal, amphibian and reptile imaginable, and even birds who walked this day rather than flew, filling the meadows behind the fence, predators at peace with prey, all crouched together on the ground, panting together, their eyes shut - but that's the next story, for a different day.
And so the next story came and went, and many after, and Autumn came and went with rain, and leaves, gold and red, and then, Winter, with her knee-deep snow and more stories on the hearth-rug in front of the fire-place in the castle's vast family room - for in the castle, the family room was for everyone who lived in the farms and shops around - and then spring came round again, bursting with bird-song and early berries and snow-melt and promises of summer, and the day came that they found themselves in the sun in the backyard again, all looking together at the now-silent volcano in the distance.
They used to just call it the mountain, specifically the Distant Mountain, but now they all called it the Volcano of Recent Memory.
Brother Eagle was so sad, and this was such an unusual state for Brother Eagle to be in that all the children were worried. They were sad, too, of course, but they feared that Brother Eagle's grief was overpowering, and at first they didn't know how to help.
Finally, Hannah asked Brother Eagle to tell them about the Old Pine Tree, and Brother Eagle told them about how, when he lost his parents while just a fledgling, the Old Pine Tree took him in, taught him the ways of the forest, persuaded Sister Wind to help him fly, cajoled the squirrels into showing him how to survive on grubs, the squirrels all the time pointing out to the Old Pine Tree that this was a very stupid thing to do, since once Little Eagle was large enough he would switch from grubs to them, and Little Eagle had to solemnly swear to never touch a hair on their heads, which, when word got round, earned Little Eagle more gifts of food from the chipmunks and woods-mice and shrews - for the littlest folk of the forest knew a good bargain when they heard it - but the rabbits, silly selfish creatures that they were, either could not be bothered or could not be convinced, so as Little Eagle grew into the giant Eagle he really was - for in those days, my dear readers, Eagles were giant creatures, almost as tall as a man when walking upright, tail dragging on the ground, wings folded behind their backs - he was able to keep his bargain with the squirrels and chipmunks and shrews and mice of all kinds - for Little Eagle chose to include all the woods-mice cousins of field, vale, thicket and stream - by gobbling happily the big, fat rabbits who had not had the sense to help, all the while talking to Old Pine each evening while the stars circled overhead and the moon came and went, learning about life…it is a good thing to learn about life from one who has lived many hundreds of little folks' life-spans, better even than very old books…and sharing his dreams.
When the day came for Little Eagle to explore the world, he had only to fly across the valley to the castle with the four children to enter into adventures beyond any normal eagle's wildest dreams.
When Brother Eagle had finished, they thought about what they might do, and Andrew suggested they make a memorial, and Max said for everyone to bring one small, precious gift to place on the memorial, and Hannah said the memorial must be where the Old Pine Tree's roots had gone into the earth, and Cameron said he was first.
So Brother Eagle took off once again toward the distant mountain, now called the Volcano of Recent Memory, and because a year had passed and the children had grown quite a lot, he found them a much heavier load than before. "Goodness!" exclaimed Brother Eagle, "how heavy you all are! I can hardly fly!"
And shortly after that he gave out a great giggle, for indeed he was so weighted down he could barely clear the trees, and the tree-tops kept tickling his belly as he flew! (If you were telling this story to little children, here you might make your one hand Brother Eagle, and the other hand pointed up like the top of a tree, and you would show how Brother Eagle would brush the tops of them, one after another, each time getting tickled and rushing upwards in a frenzy of giggles, then dropping down again because of his load to be tickled again, showing how they made their way across the forest in a long series of swoops and climbs, with great giggles from one and woops of laughter from the four, and from your listeners, until they made their way all the way to the side of the Volcano of Recent Memory.)
Here they landed in a desolate space covered in a foot of ash, and began looking for what might be left of the Old Pine Tree. At first they found only rocks and shattered pine-cones and bone-dry shards of what they would rather not think about, but after a long, arduous search largely in silence, punctuated occasionally by cries of "Oh, look!….Oh, never mind!", Brother Eagle called out confidently, "Look! Look what I have found!" and they all rushed over, each carrying their precious gift, and there, beneath the ash, green and shiny and freed by the brush of Brother Eagle's wings, stood a tiny baby pine tree.
They all sank to their knees in the ash and stared in wonder. Cameron said, "What a beautiful little baby pine tree!" Then they all hung their remembrances on it carefully, each a tiny thing that was no great weight to such a sturdy little tree: Cameron, who even though he was the youngest had called "First", a porcelain white horse so delicately cast it hardly weighed a grain of wheat; Andrew a tiny, precious snow-flake of finest glass; Max a tiny, brave sword of silver-foil; and Hannah a tiny, perfect heart of ruby set in gold leaf - and they all, all admired how everything sparkled in the sun, the green, shiny needles, the brilliantly smooth white horse, the frosty snow-flake, the gleaming silver sword, and the glowing red heart.
Brother Eagle, being an animal, had nothing to bring, but he brought his breast aching with love, and he brought something else, something none of them had expected. He brought a sudden thought.
Hesitantly, timidly, he lowered his beak alongside the little baby pine tree, and then he whispered, so quietly they could all just barely hear him, "Hello, Old Pine Tree".
And the little baby pine answered, shivering its minute needles and causing the precious things to tinkle together: "Hello, Brother Eagle".
And then the children, bursting with gladness, shouted "Hello, Old Pine Tree!" and the little pine tree shivered and tinkled to each in turn, saying "Hello, Andrew", "Hello, Max", Hello, Hannah", "Hello, Cameron", "It's so nice to see you all again."
Now here, gentle reader, a child would always, always ask: "How did the baby pine tree know Brother Eagle's name?", and I would always, always answer, "I don't know. I don't know. What do you think?" and instantly twelve voices would shout at the top of their lungs "it's the Old Pine Tree!" followed almost immediately by five other voices worrying "but how did the Old Pine Tree survive the volcano?" and, of course, this was always, always a great teaching moment - which is an awful thing, really, because children cannot be taught, they can only figure things out - where the idea would be introduced that perhaps the pine-cones, which carried seeds and which had been shattered by the heat, had thrown out seeds that gave rise to baby pines.
All, all would think about this, nod their heads in solemn understanding and then smile, satisfied at last by a well-rounded, complete, esthetically pleasing end.
But then, as we were all, all gathering ourselves in preparation for the inevitable bell, there would always, always be the tug at my elbow, the earnest little pair of eyes, the wondering lips: "but how did the baby pine tree know it was Brother Eagle?" and I would have to tell the truth: "I don't know. There are some things you just believe".
My son's Max's band Gita is opening for Theresa Andersson tomorrow, Sunday, January 4th, night at Modified Arts in downtown Phoenix!! Cool!! See you there!!
Here's a link for Theresa Andersson...be prepared to be BLOWN AWAY!! (to get the full effect, hit PAUSE in the audio player on the right of the screen, down just a little, then scroll further down and click on the movie of her in her kitchen, performing live "Birds Fly Away"!)
And here is where you can see and hear Max's and Gita's current releases (they are recording their first album as I write this!):
http://www.myspace.com/gitasound (Frankly, I don't like their most recent song, but listen to the second one, it's a great example of their work. Aaaaaaaand in both songs, listen to the lead guitar...that's Max, and I think he sounds really fine... :)
I will be posting upcoming gigs for Max and Gita here; the most current at the top each time.
What can I say? I'm proud of all my kids. When Andrew has his painting opening, or his next performance, I'll post it here, as well as when Hannah has a university dance public recital, and when Cameron is ready for Saturday Night Live....
Garrison Keillor's Writer's Almanac broadcasts - each one a short five minutes or so I believe - are my favorite thing on radio. They make me cry with happiness. He reads a poem in each one, often by current authors I've never heard of. Some of them I don't care for, but some of them are absolute gold, and I don't want to lose them. When the day comes I have extra money to spend, I intend to buy the books of poetry by the authors that I enjoyed and admired on Writer's Almanac.
Someone said, perhaps Yeats - feel free to enlighten me if you know, just use the "contact us" button at the upper right - that poems express a particular mode of consciousness that cannot be expressed in any other way, that cannot be put into words, yet in a poem, the essence is more than the sum of the words - so the result is communicating something that cannot be otherwise communicated, and which is quintessentially human...or humane.
So, this is simply a list of my favorite episodes/poems on Writer's Almanac, so I can find them when I want them (in order by favor, not by date - the top is my most favorite - the last is still a favorite, and by no means least, there are no duds in this list, but still there are favorites I can listen to daily, and favorites I'd like to revisit once a month or once a year):
(Proposals by Cecillia Woloch - wow, Garrison Keillor is on a roll! At this rate I'm going to be listing just about all of them! But, in any case, this one cannot be missed, it is about identity, a mystery of life...and it is rich with wry humor.) http://writersalmanac.publicradio.org/index.php?date=2008/12/30
(Sonnet for Mary by Ralph Edwards - Both sad and wonderful, a sonnet! It's not strictly pentameter, and it's actually fourteen heroic couplets...so it's not the rhyme scheme we expect - but I quibble...it's still a sonnet, and it's still wonderful.) http://writersalmanac.publicradio.org/index.php?date=2008/01/09
(Black Dog by James DenBoer - lest anyone suspect I only like poems with great words or humor or positive humanistic themes, here's one that is bare bones, does not moralize, has an ambiguous ending I don't understand yet and, while not "pretty", is quite compelling.) http://writersalmanac.publicradio.org/index.php?date=2008/01/06
(A Christmas Poem by William Miller - if drunks disgust you, you may find this poem aversive...or it may change your mind a little...not that I enjoy drunks, but I did enjoy this poem...we all have to struggle through life somehow; some seem to do it better than others, some get it handed to them by fortune, some get drunk, but we all can share in love.) http://writersalmanac.publicradio.org/index.php?date=2008/12/21
(Cardinals by John L. Stanizzi - a love poem, universal and intensely personal at the same time, captures an experience most humans have, at least once in their lives, differently and yet identically, defining something essential in the human condition) http://writersalmanac.publicradio.org/index.php?date=2008/12/17
(In Passing by Ted Kooser - read on Writer's Almanac on my birthday, I was curious to see what it would be. It is a superb poem, about shyness and pain and hope, and I thought it suited me well.) http://writersalmanac.publicradio.org/index.php?date=2008/12/27
(The Conjugation of the Paramecium by Muriel Rukheyser - fascinating, very subtle, very deep once you penetrate the subtlety, and I must admit it helps to know some microbiology and the miracle of conjugation - but on the other hand she gives you the essentials.) http://writersalmanac.publicradio.org/index.php?date=2008/12/15
You are welcome to adapt this poem for a child (the above
was written for a teenager about to become an adult), if you wish. T.S. Elliot
said: "Good poets imitate. Great poets steal." (Picasso said the same
thing as it applied to fine art.) If you can use this poem, in your own way, to
help support a child's (or adult's, for that matter) own aspirations and
interests - it is important that the aspirations are theirs, not your own! - by
all means steal it - or the idea of it, which is what T. S. Elliot, and
Picasso, really meant. All I ask is that if you publish it anywhere, including
posting it on the web, in a form where the original is still recognizable, that
you acknowledge who gave it to you...me. That's not much to ask, and I gladly
give it to you if it will help someone grow into or accept who they are as much
more than they thought they could be.
Regarding language and word/concept choice: I believe, when
writing a sonnet for someone, in going to the heart of the matter, their
essential character and most cherished aspirations. A sonnet, to me, should be
written in elevated language, should include beauty, beautiful words, and the
awe of life, and the subject of the sonnet should also be elevated to the
essential perfection that exists in the person, ignoring any petty human
foibles that, after all, are a part of each and everyone of us (although more
in some than others, admittedly, but in the case of Hannah, fortuitously not a
significant issue).
For me, also, it is not religious - that is, confined to any
religion - to include concepts of Heaven and God and Angels - nor is it pagan;
rather, it is my poetic expression of my personal conviction that humans have
the obligation and privilege of creating Heaven on Earth - that is what I
believe Jesus was talking about when he said, "Heaven and Earth are
One", and "As it is in Heaven, so shall it be on Earth": what we
set in the Heavens - shared belief - so shall it manifest in the Earth - our
lives and forms. A child, even a young adult, needs a parent or, lacking that,
a mentor, who will share a belief in their ability to achieve fulfillment. I'm
not talking about fame or fortune, I'm not even talking about selfish desires,
I'm talking about a child excelling in whatever they are on Earth to do,
whatever it is, so long as it in some way contributes to the wholeness of
humanity. Presidents of Ignorance, Vice Presidents of Torture and Wall Street
crooks need not apply.
For addressing children, especially, although I believe the
same for addressing adults - it's just that adults can better weather a
well-intentioned but misguided critique - but for children, even teenagers
nearing adulthood, I believe in paying attention only to the positive, the uplifting,
the best aspirations or qualities each one has. Nobody wants a poem that points
out they have a messy room, choose bad friends or can't do math. This was
something my wife taught me, but it came quite naturally to me once I
understood the idea: that by giving attention to the best in a child, the best
is encouraged to grow and express. By the same token, the praise must be rooted
in what is really there, or it has a deflating effect - this means careful and
close observation, perhaps casual conversation, to find out what is actually
harbored in the person's heart or best displayed in their actions. In someone
who has been abused, you might have to look for the tiniest clue first, for
they will likely hide away very deeply what is most sacred to them.
Have you ever heard the saying, "It ain't boastin' if
yuh done it"? Well, I can tell you that our four children are absolute
marvels, and they have turned out so well in no small part because we were
careful to observe what mattered most to each one and to give solid, but
unobtrusive, support. This is not spoiling, for those of you who, like me, grew
up with an abusive and criticizing parent, and might still carry those
misconceptions about parenting modeled so thoroughly by a confused father or
mother.
Finally, I
generally like sonnets in iambic pentameter, ten syllables to the line, but
often nine or eleven work just fine. The rhymes should be good words, not
"hut" with "butt", and I try not to stretch for an
artificial rhyme. For example, in Hannah's sonnet I had rhymed
"invisible" with "a sybil", which was awfully clever and
deliciously archaic, but, first, it didn't read out loud well - not an easy
rhyme for the ear to catch on the fly - and second, while the archaic meaning
of sybil is prophetess, the modern meaning that would be inferred by most would
be that of "Sybil", the fractured personality - so I changed it. In
those lines, "invisible" now rhymes with "sensible"; it
reads nicely, catches the ear, and even though the meaning for
"sensible" that I intend is somewhat archaic, the context helps the
reader understand I mean the older meaning of "being sensitive to",
not "practical".
As per
rhyme scheme, I usually follow the Shakespearean, which has been argued should
instead be named after Daniel, who set the example for Shakespeare, but in any
case it is as follows: abab cdcd efef gg. The final couplet, by the way, is
also known as a Heroic couplet, and in one sonnet I vary the rhyme scheme to
make the third quatrain (the third four-line stanza) out of same-rhymed heroic
couplets: eeee, so that sonnet's rhymes follow the scheme: abab cdcd eeee ff.
Someday I plan to write one that is: aaaa bbbb cccc dd. I understand fully that
the Shakespearean form usually has the best overall effect, the sustained
suspense of the alternatively rhymed lines of the quatrains culminating in the
satisfying rhymed couplet at the end, but sometimes the content calls for a
different progression, as it did in the sonnet for Cameron.
For my son Cameron, for Christmas, 2008, from Dad:*
"Cameron is just a wonderful boy"
Cameron is just a wonderful boy.
The kind of boy who makes you wonder:
What if all the world's boys could shine such joy?
What if all men-to-be came out from under
This seemingly eternal lust for strife
And instead spread love like Heaven's balm?
For the manliest need is to cherish life,
The manliest song is compassion's psalm.
Cameron is soon a man grown tall.
He walks with ease and befriends large and small.
Would he had been Adam before the Fall,
We would live there still, in nature's thrall.
For if all Earth's men would Cameron be,
Love would light all Earth and illume the Sea.
*Charles Knouse 2008 All Rights Reserved.
A few notes:
You are welcome to adapt this poem for a child (the above
was written for a teenager about to become an adult), if you wish. T.S. Elliot
said: "Good poets imitate. Great poets steal." (Picasso said the same
thing as it applied to fine art.) If you can use this poem, in your own way, to
help support a child's (or adult's, for that matter) own aspirations and
interests - it is important that the aspirations are theirs, not your own! - by
all means steal it - or the idea of it, which is what T. S. Elliot, and
Picasso, really meant. All I ask is that if you publish it anywhere, including
posting it on the web, in a form where the original is still recognizable, that
you acknowledge who gave it to you...me. That's not much to ask, and I gladly
give it to you if it will help someone grow into or accept who they are as much
more than they thought they could be.
Regarding language and word/concept choice: I believe, when
writing a sonnet for someone, in going to the heart of the matter, their
essential character and most cherished aspirations. A sonnet, to me, should be
written in elevated language, should include beauty, beautiful words, and the
awe of life, and the subject of the sonnet should also be elevated to the
essential perfection that exists in the person, ignoring any petty human foibles
that, after all, are a part of each and everyone of us (although more in some
than others, admittedly, but in the case of Cameron, fortuitously not a significant
issue).
For me, also, it is not religious - that is, confined to any
religion - to include concepts of Heaven and God and Angels - nor is it pagan;
rather, it is my poetic expression of my personal conviction that humans have
the obligation and privilege of creating Heaven on Earth - that is what I
believe Jesus was talking about when he said, "Heaven and Earth are
One", and "As it is in Heaven, so shall it be on Earth": what we
set in the Heavens - shared belief - so shall it manifest in the Earth - our
lives and forms. A child, even a young adult, needs a parent or, lacking that,
a mentor, who will share a belief in their ability to achieve fulfillment. I'm
not talking about fame or fortune, I'm not even talking about selfish desires,
I'm talking about a child excelling in whatever they are on Earth to do,
whatever it is, so long as it in some way contributes to the wholeness of
humanity. Presidents of Ignorance, Vice Presidents of Torture and Wall Street
crooks need not apply.
For addressing a child with a poem, especially with a sonnet - although I believe the
same for addressing adults - it's just that adults can better weather a
well-intentioned but misguided critique - but for children, even teenagers,
even adults! - I believe in paying attention only to the positive, the
uplifting, the best aspirations or qualities each one has. Nobody wants a poem
that points out they have a messy room, choose bad friends or can't do math.
This was something my wife taught me, but it came quite naturally to me once I
understood the idea: that by giving attention to the best in a child, the best
is encouraged to grow and express. By the same token, the praise must be rooted
in what is really there, or it has a deflating effect - this means careful and
close observation, perhaps casual conversation, to find out what is actually
harbored in the person's heart or best displayed in their actions. In someone
who has been abused, you might have to look for the tiniest clue first, for
they will likely hide away very deeply what is most sacred to them.
Have you ever heard the saying, "It ain't boastin' if
yuh done it"? Well, I can tell you that our four children are absolute
marvels, and they have turned out so well in no small part because we were
careful to observe what mattered most to each one and to give solid, but
unobtrusive, support. This is not spoiling, for those of you who, like me, grew
up with an abusive and criticizing parent, and might still carry those
misconceptions about parenting modeled so thoroughly by a confused father or
mother.
Finally, I generally like sonnets in iambic pentameter, ten
syllables to the line, but often nine or eleven work just fine. The rhymes
should be good words, not "hut" with "butt", and I try not
to stretch for an artificial rhyme. For example, in Hannah's sonnet I had
rhymed "invisible" with "a sybil", which was awfully clever
and deliciously archaic, but, first, it didn't read out loud well - not an easy
rhyme for the ear to catch on the fly - second, while the archaic meaning of
sybil is prophetess, the modern meaning that would be inferred by most would be
that of "Sybil", the fractured personality - so I changed it. In
those lines, "invisible" now rhymes with "sensible"; it
reads nicely, catches the ear, and even though the meaning for
"sensible" that I intend is somewhat archaic, the context helps the
reader understand I mean the older meaning of "being sensitive to",
not "practical". As per rhyme scheme, I usually follow the
Shakespearean, which has been argued should instead be named after Daniel, who
set the example for Shakespeare, but in any case it is as follows: abab cdcd
efef gg. The final couplet, by the way, is also known as a Heroic couplet, and
in the sonnet above I vary the rhyme scheme to make the third quatrain (the
third four-line stanza) out of same-rhymed heroic couplets: eeee, so that
sonnet's rhymes follow: abab cdcd eeee ff. Someday I plan to write one that is:
aaaa bbbb cccc dd. I understand fully that the Shakespearean form usually has
the best overall effect, the sustained suspense of the alternatively rhymed
lines of the quatrains culminating in the satisfying rhymed couplet at the end,
but sometimes the content calls for a different progression, as it did in the
sonnet for Cameron.
He can swing high, he can swing low, lead them all
In a sweet tip-toe. At dusk, light the dawn,
At dawn, dark the night, and then, for love, call
God's muses to choir Heaven upon.
Max is a musician with perfect grace,
A man with rapture for the human race.
*Charles Knouse 2008 All Rights Reserved.
A few notes:
You are welcome to adapt this poem for a child (the above
was written for a teenager about to become an adult), if you wish. T.S. Elliot
said: "Good poets imitate. Great poets steal." (Picasso said the same
thing as it applied to fine art.) If you can use this poem, in your own way, to
help support a child's (or adult's, for that matter) own aspirations and
interests - it is important that the aspirations are theirs, not your own! - by
all means steal it - or the idea of it, which is what T. S. Elliot, and
Picasso, really meant. (For example, there is, in the above sonnet for Max, a bold allusion to Sir Philip Sydney's finest sonnet, To Stella.) All I ask is that if you publish it anywhere, including
posting it on the web, in a form where the original is still recognizable, that
you acknowledge who gave it to you...me. That's not much to ask, and I gladly
give it to you if it will help someone grow into or accept who they are as much
more than they thought they could be.
Regarding language and word/concept choice: I believe, when
writing a sonnet for someone, in going to the heart of the matter, their
essential character and most cherished aspirations. A sonnet, to me, should be
written in elevated language, should include beauty, beautiful words, and the
awe of life, and the subject of the sonnet should also be elevated to the
essential perfection that exists in the person, ignoring any petty human
foibles that, after all, are a part of each and everyone of us (although more
in some than others, admittedly, but in the case of Max, fortuitously not a
significant issue).
For me, also, it is not religious - that is, confined to any
religion - to include concepts of Heaven and God and Angels - nor is it pagan;
rather, it is my poetic expression of my personal conviction that humans have
the obligation and privilege of creating Heaven on Earth - that is what I
believe Jesus was talking about when he said, "Heaven and Earth are
One", and "As it is in Heaven, so shall it be on Earth": what we
set in the Heavens - shared belief - so shall it manifest in the Earth - our
lives and forms. A child, even a young adult, needs a parent or, lacking that,
a mentor, who will share a belief in their ability to achieve fulfillment. I'm
not talking about fame or fortune, I'm not even talking about selfish desires,
I'm talking about a child excelling in whatever they are on Earth to do, whatever
it is, so long as it in some way contributes to the wholeness of humanity. Presidents
of Ignorance, Vice Presidents of Torture and Wall Street crooks need not apply.
For addressing children, especially, although I believe the
same for addressing adults - it's just that adults can better weather a
well-intentioned but misguided critique - but for children, even teenagers, I
believe in paying attention only to the positive, the uplifting, the best
aspirations or qualities each one has. Nobody wants a poem that points out they
have a messy room, choose bad friends or can't do math. This was something my
wife taught me, but it came quite naturally to me once I understood the idea:
that by giving attention to the best in a child, the best is encouraged to grow
and express. By the same token, the praise must be rooted in what is really
there, or it has a deflating effect - this means careful and close observation,
perhaps casual conversation, to find out what is actually harbored in the
person's heart or best displayed in their actions. In someone who has been abused,
you might have to look for the tiniest clue first, for they will likely hide
away very deeply what is most sacred to them.
Have you ever heard the saying, "It ain't boastin' if
yuh done it"? Well, I can tell you that our four children are absolute
marvels, and they have turned out so well in no small part because we were
careful to observe what mattered most to each one and to give solid, but
unobtrusive, support. This is not spoiling, for those of you who, like me, grew
up with an abusive and criticizing parent, and might still carry those
misconceptions about parenting modeled so thoroughly by a confused father or
mother.
Finally, I generally like sonnets in iambic pentameter, ten
syllables to the line, but often nine or eleven work just fine. The rhymes
should be good words, not "hut" with "butt", and I try not
to stretch for an artificial rhyme. For example, in Hannah's sonnet I had
rhymed "invisible" with "a sybil", which was awfully clever
and deliciously archaic, but, first, it didn't read out loud well - not an easy
rhyme for the ear to catch on the fly - second, while the archaic meaning of
sybil is prophetess, the modern meaning that would be inferred by most would be
that of "Sybil", the fractured personality - so I changed it. In
those lines, "invisible" now rhymes with "sensible"; it
reads nicely, catches the ear, and even though the meaning for
"sensible" that I intend is somewhat archaic, the context helps the
reader understand I mean the older meaning of "being sensitive to",
not "practical".
As per rhyme scheme, I usually follow the
Shakespearean, which has been argued should instead be named after Daniel, who
set the example for Shakespeare, but in any case it is as follows: abab cdcd
efef gg. The final couplet, by the way, is also known as a Heroic couplet, and
in the sonnet above I vary the rhyme scheme to make the third quatrain (the
third four-line stanza) out of same-rhymed heroic couplets: eeee, so that
sonnet's rhymes follow: abab cdcd eeee ff. Someday I plan to write one that is:
aaaa bbbb cccc dd. I understand fully that the Shakespearean form usually has
the best overall effect, the sustained suspense of the alternatively rhymed
lines of the quatrains culminating in the satisfying rhymed couplet at the end,
but sometimes the content calls for a different progression, as it did in the
sonnet for Cameron.
For my son Andrew, for Christmas, 2008, from Dad:*
"Andrew is an artist, fierce, free and wild"
Andrew is an artist, fierce, free and wild,
He could throw dirt at cats, and once they've fled,
There would remain, astonishing, an earth-fleshed child,
Cat-like, feral, but out of a human bed.
He paints with essence, peanut-butter, pears,
With gouts of blood from his opened chest,
With rays of blue and yellow thrown down stairs,
And sprinkled with gemstones from a starry nest.
View works of Andrew and you gaze at God,
Playing with light like drumsticks on prism'd glass,
Careless of frowns, splashing paint with feet unshod,
He laughs at clouds and to canvas breathes mass.
Andrew is a painter with molten gold,
Untarnished visions all Heaven wants told.
*Charles
Knouse 2008 All Rights Reserved.
A
few notes:
You
are welcome to adapt this poem for a child (the above was written for a
teenager about to become an adult), if you wish. T.S. Elliot said: "Good
poets imitate. Great poets steal." (Picasso said the same thing as it
applied to fine art.) If you can use this poem, in your own way, to help
support a child's (or adult's, for that matter) own aspirations and interests -
it is important that the aspirations are theirs, not your own! - by all means
steal it - or the idea of it, which is what T. S. Elliot, and Picasso, really
meant. (There is a bold allusion to Wallace Steven's Sunday Morning in
the above sonnet, for those of you who know Stevens.) All I ask is that if you
publish it anywhere, including posting it on the web, in a form where the
original is still recognizable, that you acknowledge who gave it to you...me.
That's not much to ask, and I gladly give it to you if it will help someone
grow into or accept who they are as much more than they thought they could be.
Regarding
language and word/concept choice: I believe, when writing a sonnet for someone,
in going to the heart of the matter, their essential character and most
cherished aspirations. A sonnet, to me, should be written in elevated language,
should include beauty, beautiful words, and the awe of life, and the subject of
the sonnet should also be elevated to the essential perfection that exists in
the person, ignoring any petty human foibles that, after all, are a part of
each and everyone of us (although more in some than others, admittedly, but in
the case of Andrew, fortuitously not a significant issue).
For
me, also, it is not religious - that is, confined to any religion - to include
concepts of Heaven and God and Angels - nor is it pagan; rather, it is my
poetic expression of my personal conviction that humans have the obligation and
privilege of creating Heaven on Earth - that is what I believe Jesus was
talking about when he said, "Heaven and Earth are One", and "As
it is in Heaven, so shall it be on Earth": what we set in the Heavens -
shared belief - so shall it manifest in the Earth - our lives and forms. A
child, even a young adult, needs a parent or, lacking that, a mentor, who will
share a belief in their ability to achieve fulfillment. I'm not talking about
fame or fortune, I'm not even talking about selfish desires, I'm talking about
a child excelling in whatever they are on Earth to do, whatever it is, so long
as it in some way contributes to the wholeness of humanity. Presidents of
Ignorance, Vice Presidents of Torture and Wall Street crooks need not apply.
For
addressing children, especially, although I believe the same for addressing
adults - it's just that adults can better weather a well-intentioned but
misguided critique - but for children, even teenagers nearing adulthood, I
believe in paying attention only to the positive, the uplifting, the best
aspirations or qualities each one has. Nobody wants a poem that points out they
have a messy room, choose bad friends or can't do math. This was something my
wife taught me, but it came quite naturally to me once I understood the idea:
that by giving attention to the best in a child, the best is encouraged to grow
and express. By the same token, the praise must be rooted in what is really
there, or it has a deflating effect - this means careful and close observation,
perhaps casual conversation, to find out what is actually harbored in the
person's heart or best displayed in their actions. In someone who has been
abused, you might have to look for the tiniest clue first, for they will likely
hide away very deeply what is most sacred to them.
Have
you ever heard the saying, "It ain't boastin' if yuh done it"? Well,
I can tell you that our four children are absolute marvels, and they have
turned out so well in no small part because we were careful to observe what
mattered most to each one and to give solid, but unobtrusive, support. This is
not spoiling, for those of you who, like me, grew up with an abusive and
criticizing parent, and might still carry those misconceptions about parenting
modeled so thoroughly by a confused father or mother.
Finally,
I generally like sonnets in iambic pentameter, ten syllables to the line, but
often nine or eleven work just fine. The rhymes should be good words, not
"hut" with "butt", and I try not to stretch for an
artificial rhyme. For example, in Hannah's sonnet I had rhymed
"invisible" with "a sybil", which was awfully clever and
deliciously archaic, but, first, it didn't read out loud well - not an easy
rhyme for the ear to catch on the fly - and second, while the archaic meaning
of sybil is prophetess, the modern meaning that would be inferred by most would
be that of "Sybil", the fractured personality - so I changed it. In
those lines, "invisible" now rhymes with "sensible"; it
reads nicely, catches the ear, and even though the meaning for
"sensible" that I intend is somewhat archaic, the context helps the
reader understand I mean the older meaning of "being sensitive to",
not "practical".
As
per rhyme scheme, I usually follow the Shakespearean, which has been argued
should instead be named after Daniel, who set the example for Shakespeare, but
in any case it is as follows: abab cdcd efef gg. The final couplet, by the way,
is also known as a Heroic couplet, and in one sonnet I vary the rhyme scheme to
make the third quatrain (the third four-line stanza) out of same-rhymed heroic
couplets: eeee, so that sonnet's rhymes follow the scheme: abab cdcd eeee ff.
Someday I plan to write one that is: aaaa bbbb cccc dd. I understand fully that
the Shakespearean form usually has the best overall effect, the sustained
suspense of the alternatively rhymed lines of the quatrains culminating in the
satisfying rhymed couplet at the end, but sometimes the content calls for a
different progression, as it did in the sonnet for Cameron.
Yet another short article that will be expanded later.....really! No, I mean it!!!
I had an epiphany today. Many of the technical problems we talk about in audio amps, including tube amps, are problems that only exist due to cost to manufacturers. The pressure to make an ever-increasing profit...for corporations (we really need to do something about corporations - they have all the rights of individuals, and virtually none of the accountability or liability each of us have)...or the intense pressure to just stay alive, for the privately held amp-maker garage-setup company...creates devil's choices of how to get good sound without spending so much on components and fabrication that profit goes right out the window.
These problems do not need to be an issue for DIY'ers. Yeah, we have cost issues, all right, and a favorite topic on tube forums is the "junk box" amp...it's FUN to take a bunch of junk that's piled up over the years and make a half-decent amp out of it.
But we don't pretend...I hope not...that the junk-box amp is GREAT. It's just reasonably good, and cheap, and a great way to make old stuff useful. One can always use another tube amp. Laundry room, garage, outhouse....
As DIY'ers, we have the wonderful opportunities to burn-up (or cut in half) "straw-men" all over the place. In this article, as I accumulate them, I'll be listing them here. Submissions are welcome; I like to attribute other authors, so you're welcome to submit, I won't steal your work, I'll publically thank you.
The first straw-man, which I've made a BIG DEAL about in other parts of this blog, is the matter of "blocking". (See the article "What Transformation Audio is All About", considerably far down the page; I don't want to copy it all here, because it would just slow you down here if you've already read it...later I'll put a link here about "blocking" if you don't know what it is). And I talk about direct-driving the output stage, with direct coupling, using a cathode-follower stage or mosfet-follower stage or TubeLab's PowerDriver circuit (see links on right)...but looking at Max's superb EL-34 power amp at AngelFire (see link near top on right)...I had this epiphany.
"Wait a sec....." I sez to myself, I sez, "Max drives the output tubes with cathode-followers (good)...but the cathode followers are capacitor coupled to the output EL-34's....why not direct-couple?....wouldn't blocking be a potential problem?"...and then it hit me: "Ahah!!!!!!!!! Blocking is only a problem in amps where you're trying to save cost by beating the crap out of a single output tube, instead of paralleling enough of 'em to avoid the problem altogether!!"
"Blocking" is only a problem if you're pushing the output stage tubes to the limit. If you parallel enough tubes (or enough mosfets, heh heh heh), you have so much reserve power - assuming you're running the amp at sane volume levels, of course - that the output stage never gets whacked to the ceiling or slammed to the floor. This means you can capacitor couple to the output stage without worrying about "blocking".
A beautiful example of Cutting the Gordion Knot! (see "Wonderful Links for LEARNING about tubes, electronics, mosfets & transistors").
Max wanted extremely low distortion in the output stage BEFORE negative feedback, so he wouldn't need to use much negative feedback (with his design, you could do without negative feedback altogether, if you want). How to do this? The same way you get low distortion with ANY tube: run the tube with only a small portion of it's potential signal-swing capability used. I'll put a diagram in here later to demonstrate what this means, you'll understand instantly when you see it. (I have to figure out how to do that in code; the blog-ware won't let me do it directly, but no big deal, just time).
So, Max used an ELEGANT solution (not a simple...as in "simple-minded"...solution...different than elegant): he used multiple output tubes in parallel, so he could get good power WITHOUT pushing the tubes near their limits. (He essentially made the output stage into more of a CURRENT device than a VOLTAGE device; by paralleling the tubes, he gets lower plate resistance, higher current, and a more efficient impedance match to the output transformer...I'll post an explanation of this, with math, later). Aaaaand how he doesn't need to push one tube to it's max....the quartet of EL-34's kinda loaf along, and transients, if they clip, are clipped softly, and don't cause "blocking". See? How cool, huh?
So, we now kinda have two legends/myths transmogrified (Calvin and Hobbes) into one: Cutting the Gordion Knot, and Straw Men: Cutting Straw-Men in Half with a Mighty Bronze Sword!! Cooooooooool.
This is a short article that will be expanded later. I think I found a little jewel of a forum (below).
Over the years, I have encountered audiophool products and contraptions I thought were absolutely hilarious.
When I first ran into the idea of room dampers....huge chunks of foam in the corners, or panels of acoustic absorption material, or round foam pillars placed here and yon....I laughed till I cried. But then a fellow from France who is one of the world's great DIY transformer winders told me that these were not audiophoolery at all, that they can tame room reflections to clean up the bass remarkably. So I repented...at least on this one.
Maybe because I have a preference for living in houses where there are ridiculously tall ceilings and large rooms and plenty of rugs and cushioned leather upholstery and bookshelves full of...books, mostly...I never really noticed this as a problem. But I have yet to be able to afford really good speakers....except for the AR's I had in BackBay Boston in the early '70's that fried my Heathkit transistor amp....wish I had 'em back! Now that I know how to build an amp to drive 'em!...so the cheap bookshelf units, set to point right at my head, not awfully far away, sound great, and I don't notice room "nodes"...places where the reflections, mostly in the bass I believe, either cancel or add, causing disturbing dips or peaks in frequency and destroying clarity in the bass...because I am practically wearing "open-air" headphones.
But, if you are handicapped by a smaller room, or a very (acoustically) bright room, or speakers with separate subs, or need to satisfy the desires of several people in different listening positions, or you like to "roam" while you're listening - and there's a clarity problem in the bass or maybe lower midrange - then "room treatment" might be just the thing for you. Because I don't know of any speakers or amp or equalizer that can really tame an awful sounding room....well, not within my budget, anyway, I'm sure there are some out there that claim they can do it...
but why not just make some cheap foam dampers yourself, have fun moving them around, give the cats something new to destroy,the dogs new things to pee on,the kids new places to hide while playing air-soft (ouch!), and give your loverly/handsomerly other a new reason to wonder why she/he ever married you?
Aaaaaaaaaaaanyway, I found this great group, an "Audio Circle", devoted to just this topic, and these DIY'ers are great! They know their stuff, they are FUNNY, and the forum is a delight to behold. Did I say they are FUNNY? I didn't find any insulting behaviour....well, except to manufacturers of REALLY EXPENSIVE STUFF....but it was reasonably good-natured, and when the manufacturer chimed in they treated him politely and some even offered to stop in for a listen...but I didn't examine each and every thread, so let me know if I missed something. I would lurk here at first; there's so much great info and links, if you're new to treating room acoustics, I'd bet an old AA-100 (before modding, not after...) what you need is already there. And this place is better than any sit-com on TV (except your favorite one, of course).
By the way, those really expensive hand-turned wooden thingies for treating room acoustics, and stuff like that? If you are rich, please buy them, you'll help someone who can't hold a real job make a living (JUST KIDDING...if you think that joke was mean, let me know, I'll take it out).
Actually, I do think one of the purposes of Rich People is to support pioneers, people who stretch boundaries...so I don't see a real difference between a Rich Person buying a painter's painting or a $3,000 hand-quenched room resonator. Just because I can't afford it, I really shouldn't put down products intended for....Rich People. Certainly not intended for me! (Hmmmm........if you are a Rich Person reading this, you really should contact me, because I have a research project I NEED funding for....not kidding there, either, but enough on that....)
If you're not a Rich Person, take chunks of wood from the woodpile and hack at them with a hatchet until you've rounded them up a bit, and gather nicely-rounded-by-nature rocks from a stream or the beach, and then place them hither and yon in your listening room - after a round-trip to the ER to sew your thumb back together - until whatever sound reflection that's bugging you is sufficiently busted up (just like it happens in nature, although I admit leaves, grass and open sky certainly help), and then please send me a photo to post. I'm not kidding!....but only if you really did it and it really helped...OK?
Now, that just gave me an idea....acoustically tuned "tall-grass" carpet to stop those floor reflections...teflon with micro-platinum crystals...complete with a stalking robotic ocelot programmed to find nodes and pounce on them, but with the Five Laws of Robotics included:
the fourth one being "Don't Eat Human Children, Even if They Do Look Like Rug-Rats";
and the fifth one being "Always Obey Will Smith"....
By the way, you know those anechoic chambers really big companies have,
like JBL, I think, for testing loudspeakers in...so there are no nodes,
nulling or additive? With the foam spikes sticking out from all the
walls? Well, if you did that to your listening room, you'd hear your
loudspeakers unadorned...but they'd sound kinda dull. A certain amount
of room reverberation adds life to the sound; that's why guys like
Linkwitz (see links on the right)...who is a genius...make dipole
speakers, with big panels that are nonetheless open, not a ported box
like a bookshelf speaker...so the reverberations will sound the same as
if you had the Cleveland Symphony, with doubled violins, crammed into
your living room.
Also by the way, you can approximate pretty well and anechoic chamber
by simply putting the loudspeaker in question on the grass in a large
space, seal around it somehow so you don't get the back-reflections,
and point it at the sky! Or, you could mount the speaker in a big piece
of plywood or plaster board and lay that on the grass, again, pointing
at the sky. Then you put a mic on a boom over it at the distance you
want, and take measurements. Or...it gets better...you could just dig a
hole in the ground and "ground-mount" the speaker to be tested! (These
two items I learned on the forum whose link is below....see what I mean
about a little jewel of a forum?)
Later on, maybe I'll post a list of links to stuff for "Rich People"....really! (blast it, I can't get bolding to turn off now, there's something wrong with this $&$#@@!! text editor for this blog-ware). It's fun to look, although I admit I get a tinge of jealousy sometimes, wishing I could just buy one of them just for the fun of it.
By the way, I THINK I've figured out how to enable comments with moderating....that is, I see them first, so: Note: nutcases just know that I'll delete at the first HINT of a nutcase comment and will not bother to read the whole thing....so tell me what you think of this audio-circle forum - if I got it right or not.
I'm just getting the link in here, with a few words.
Unlike audioasylum, which I'll get to later, which can be kinda crazy, but has some really intelligent people on it and the occasional post from a world-expert...or GeeK_ZonE, which is kind of a closed club where you enter at some peril...
diyaudio seems a safe place and a place where a lot of really practical people who like to make things like to hang out.
I don't know which forums came first, but the vast width and breadth and depth of diyaudio makes me suspect they must have been pretty close to the front of the line when God was handing out forum features...
I call it the Mother of Forums because it is so big, because it is generally a safe place to be, and because the tone is warm, kinda...furry. You know, like the rug-covered wooden "mother" that rather cruel psychologist/researcher (his name escapes me as I write this but it will come back to me overnight...or just as I'm about to go to sleep after having turned OFF the computer...), gave the monkey (chimp?) baby to cling to, to test his theory about emotional development requiring soft cuddling during the infant stage...
On the other hand, as is the case in ANY forum, there are the usual irritating - but fairly occasional, not usually a mob - "experts" who have the last word. Who make BIG GENERALIZATIONS AS FINAL TRUTH:
As in: show me how an op amp can possibly hurt sound. Or: dipole speakers sound dead, lack focus.
Which is all nonsense. Later I'll list more silly over-generalizations. I have been guilty of making them myself, and I'm sure a few have crept into this blog...where I have gone overboard, I'll eventually notice and fix it. But I do stick to my guns about blinding tests (see Listen Up!).
But at diyaudio there's a real effort by members and moderators to...well, MODERATE...extreme views, big over-generalizations, by "soap-box" individuals.
So, this is a good forum for the beginner to join, or the expert to join who hadn't happened to find them yet.
You want to join, because unless you join, you can't see the attachments. Attachments are important!!!
But, remember (blast it, now the bolding is turned on again...arrrg), just because you joined, doesn't mean you need to post. REALLY. Read my article about joining forums without making a nuisance of yourself. diyaudio is so big...ahhh, that's the other reason I call it "the Mother of forums", it's kinda like those ancient fertility sculptures, the ones with ENORMOUS breasts and butts....that you can probably find all the info you need by reading...reading...reading...without having to post a question that's already been answered, in depth, a long time ago (or the thread started, a long time ago).
Now, if you have something valuable to add to an old thread....or, after studying the thread and googling your questions....you still have a question you'd like answered...by all means, add your question to the thread! I love it when somebody rejuvenates an old thread...it's like bringing something dead back to life. Now we've gone Egyptian!
Sometimes trying to rejuvenate an old thread doesn't work. Maybe it's so old it's archived. Maybe a newer thread has replaced it in the minds of the members, so your post gets ignored. This can happen. Don't get insulted, nobody means to snub you, they just didn't notice. If this happens, check for a newer thread. If no newer thread, then, hey, start a new one with your question.
The web, in my opinion....IF we can keep it FREE...free from censorship, free access for all......is the next step in the evolution of mankind.
It enables people to learn just about anything, and this is especially true of electronics. There are so many wonderful teachers of electronics on the web, who just want to share. Maybe they make a nickel or two from site visitors, and that's a good thing...I know for sure they're not getting rich, it really is a labor of love. So, I've chosen sites where you can learn everything you need to know to design and build good tube and mosfet and transistor amps just like the pro's. The essentials of a good amp were well known 70 years ago; the only thing that's changed is we have a lot more options now: Constant Current Devices (CCS's), far better transformers, mosfets, op amps, transistors, and so on.
All you really need for a great amp is good transformers, some decent tubes, and a good, solid topology. You do NOT need silver wire, gold plated switches, special tubes cryogenically treated, and super expensive capacitors. YOU DO NOT!!! (Although you DO want to avoid paper capacitors). The most important thing about an amp is THE TOPOLOGY (type of circuit). The second most important thing about an amp are the TRANSFORMERS (except for mosfet output amps, of course, heh heh heh). The third most important thing about an amp are APPROPRIATE TUBES FOR THE TOPOLOGY...AND THEY DON'T HAVE TO BE EXPENSIVE.
Do not believe the hype. And, if you pay attention to the tutorials, you will come to understand that biasing a cheap tube properly, driving it properly, and loading (or, really, unloading) the plate properly, and in some cases protecting it from vibrations that might cause microphonics, will give you far better sound than the most expensive tube in the world not set up correctly.
"Tube rollers" would have you believe that certain brands of the same tube are better than others, etc., and while there's SOME truth to that, don't get your knickers all twisted up about it....a cheap tube properly set up can still sound better than a ridiculously expensive NOS Mullard with black plates, etc., not set up just right. And then, when you add in the fakes on the market, expensive collector's items that are really junk from China relabeled, you start to understand that there's a lot of snobbery involved in tubes that you do NOT have to buy into.
After that, it gets subtle. Types of resistors, etc. Avoid paper caps, etc. So, after the educational links, I'm going to include great examples of circuits, circuits you could just go ahead and build, circuits you can learn from by applying your understanding to them. Every great amp circuit...and there are hundreds of them...teaches you something about electronics. Sometimes it's subtle, sometimes it's one of those things that hits you between the eyes and you go: "Doh!" - but either way, you've learned something.
I will also list here books - the best of the best - you can purchase to deepen your understanding, and which include projects you can build, also.
One word about projects: there are four main categories (these are kind of like tornado categories...be wary of a category 4!!):
Category 1: Decent amp projects that don't cost too much and aren't huge and heavy but which will give you a great deal of satisfaction and quite good sound;
Category 2: Really good amp projects that incorporate new ideas and have, I think, some conceptual breakthroughs in them...some complicated, some amazingly simple; some cheap, some expensive;
Category 3: Great amp projects that cost a lot and/or require much greater technical and electronic skills (NOT for beginners....REALLY!!);
and Category 4: Great amp projects that have a WOW factor but are really, for most people, simply impractical - way too big, way too high voltage, way too complicated. I'll list them so you can look at them and go WOW, and drool a little, but please don't build them - they really are impractical, they really are. Build some Category 1's before you even think about building a Category 2 or 3...and tell your spouse to STOP YOU if you start talking for real about building a Category 4...but they're still fun to dream about.....
SO, LET'S GET STARTED:
LINKS FOR LEARNING ABOUT ELECTRONICS AND TUBES, IN PRIORITY ORDER!!! DO #1 FIRST...REALLY!!!!
1. START HERE: These links are at Max's AngelFire site...don't underestimate these pages, they give you foundational understanding that you must have. Once you've mastered these pages, then you can go on...but not before; if you jump ahead, you'll just cheat yourself.
To start at DC basic electronics, go here (this means you, unless you're already an EE (Electrical Engineer):
either way, do them all, from start to finish. IF you already are an EE, but only got trained in transistors and need to get brushed up on tubes, you could start here:
All done with AngelFire's tutorials? You DID read them all, right? You DIDN'T skip any, right? You at least tried to do some of the problems yourself first? Good for you! Now you have the basics you need. Let's move ahead to articles that give you a more global understanding of audio amplification...later, we'll come back to highly specific (and full of math, but math that makes sense) articles that focus in on particularly important topics. 2. NOW GO HERE:
This is Rod Elliot's site, one of the world's best. READ ALL THE PAPERS. The link above is where you start, but you can just go to the main page and click on the articles link to see the index of all of them, if you wish:
Don't worry that many of the papers are about SS amps. You may find that you'd just as soon go SS, and use Rod Elliot's PCB's or Kits. That's cool. Tubes are fun, they glow, they have a special sound, but they are also a downright hassle compared to SS. You might find it's easier to make your first amps SS using products such as Elliot's. You certainly couldn't go wrong.
I remember one of the finest, clearest, most incredibly realistic sound I ever heard was Art Garfunkle's first solo album (remember that? it had it's appeal...) through a Heathkit SS amp through Acoustic Research speakers...until I turned up the volume a hair too high, and the impedance dips in the AR speakers crossovers completely FRIED the ouput transistors of the Heathkit amp. What a bummer!
I doubt you'd have this problem with any designs by Max at AngelFire or Elliot at Rod Elliot's, design has come a long way in terms of protecting the amp from nasty impedance dips from speakers since the 1970's.
Have you read all of Rod Elliot's articles? You are way down the road now to being an expert DIY'er, and you haven't built anything yet! You COULD at this point choose a project from either of the two sites recommended above, just to get your feet wet, get something built, and feel the satisfaction. Don't worry if it's a small amp...later on, you'll like having a tiny amp in your bathroom, kitchen or by your computer...and then can move on to building a much bigger amp for your dedicated listening space.
You may notice some various small points of disagreement, or different philosophies, between Max's site and Elliot's site. Welcome to the world of being an audiophile (not audiophool)!
By the time you're done with the full set of links I'm going to put here, you will find some very BIG disagreements...which is cool, because, A: Build one of each, and then compare! Decide for yourself! B: As you learn more, you'll see that some of the disagreements are simply about the advantages and disadvantages of different topologies and components, and you'll find you can make distinctions from your own understanding and experience and feel great about going down a particular path. For example, the day I decided to give up on the idea of winding my own Output Transformers, a huge weight lifted off me. I had cut a "Gordion Knot"...and now I know precisely where I personally want to go with design: replacing the OPT with mosfet circuits. Now I'm happy. I can't afford good output iron. I can't afford the TIME to become a master DIY winder of my own OPT's. But I CAN figure out how to use mosfets instead of OPT's well. Now, if you want to become a master DIY winder of OPT's, go for it!!!! You'll be one of the rarest of audiophile DIY'ers. Later in this set of tutorial links I'll give you links to sites where you can learn how to wind the best of the best.
The Legend of the Gordion Knot is very important to understand, especially if you want to be an audiophile DIY'er. Otherwise, you might just go nuts..........I'll explain the Legend of the Gordion Knot, and what it means for helping each DIY'er come to peace with what they want to achieve, tomorrow...
Here's the legend. Now, note that it's not a myth....historians are pretty sure this really happened, or a reasonable version of it...so it's a legend, not a myth. A myth is a story so old that the origins of the story are lost in time, and often it's so old the origins predate the written word. A myth also contains symbolic language or concepts that are sacred, or philosophical, or describe creation. A myth is neither false nor true...it's value is it's symbolic or sacred meaningfulness.
A legend is generally a true story that is heroic or awe-inspiring in some way. My favorite legend is the Legend of the Gordion Knot.
We go back in time to Alexander the Great, 333 BC. Wow, that was a long time ago. He set out, after being taught the history and philosophy of the Greeks by Aristotle, to conquer the known (and unkown) world. Why? For the same reason most conquerors give: to bring peace, prosperity and order. Of course, a lot of innocent people die along the way, so I'm not so thrilled about that part; that isn't what makes Alexander great to me.
But Alexander did something legendary that was of mythic proportion - meaning that it has a lesson for all of us. Now, Alexander, remember, was tutored by Aristotle. He was familiar with logic, with math, with solving problems, and he also knew about unsolvable problems. For example, Alexander had surely been taught by Aristotle that it was impossible, using the tools of geometry at the time - the compass, string, the right angle, and so on - to square a circle. That is, take a circle, and then find the square of it that would have precisely the same area. Aristotle could not have known that over 2,000 years later, that problem would remain unsolvable, by the most powerful computers and mathematicians available to mankind; he may have believed it really would be solvable some day. But I digress!
When Alexander was beginning his campaign to conquer all of Asia, to bring the wisdom of the Greeks to all the "barbarians" of the Persian Empire and the unknown-but-hinted-at lands beyond, he, with his army, came to the town of Phrygia in an outer province of Persia. Here was kept the Gordion Knot, the knot which could not be untied. It is theorized that this was a knot which had the two ends spliced together, so there were no free ends, and moreover which had been tied wet and then dried in the sun so that it shrunk, and was so tight that not only could you not manipulate any part of it, but that even if you did find a free end - which there was none - no part of it could be loosened enough to allow any untieing to take place.
In any event, Alexander was no dummy. He is said to have played with the knot for a brief time, until he had satisfied himself in his own mind that there was no point in attempting to untie it. Then came the moment of suspense. What would he do? Now, the seers of the time in that town - the priests of whatever religion the Persians were operating under, I'm sure whatever it was it was akin to Egyptian religion - strange, complex, allegorical, and ultimately unfathomable - had challenged Alexander to untie the knot, because the myth was that whoever could untie it would go on to conquer all of Asia. Since that was precisely what Alexander had in mind, and everyone knew it, the stakes were high. He HAD to untie that knot. He knew it. His soldiers knew it. The priests, laughing up their sleeves, knew it. But Alexander knew quite well that it was impossible to untie it as it was; it was a trap to defeat him before he got started.
So Alexander did the unexpected, and in doing so, performed one of the most brilliant strokes of genius in the history of humankind.
He drew his sword and cut the blasted thing in half. Voila! Lots of free ends, nicely loosened up, and now easy to unravel.
The allegory is this: we humans present ourselves with unsolvable problems all the time. We make mental barriers of all sorts in life, finding ourselves stuck in jobs we seemingly can't get out of, perhaps stuck in a relationship, perhaps a problem with a child that seems unsolvable. But the problem is not the job, not the relationship, not the child. The problem is our own belief that we cannot find a way to cut the knot in half!
I don't mean to preach. I do not underestimate the magnitude of the challenges we all have to face. But there is always a way to cut the knot in half, unravel it, and begin anew. Always.
I will give you one example I observed recently, and then move on, back to electronics and tubes. Just to illustrate what I mean. A co-worker at work has been having enormous difficulties with their teen-age daughter. And yet, as I've observed the drama of ever more-intense phone calls over the past several months, I was struck by how confrontational this person was. This person was constantly causing ruckuses with all sorts of co-workers. Not with me, because I can get along with just about anybody. I would draw the line at a Stalin or Hitler or Mussolini or Weird Al Yankovic (KIDDING), but basically I like people and do my best to treat everyone with equal respect and kindness.
Which is why I have no tolerance whatsoever for forums that do not delete insults. Insults are not acceptable to start with, and leaving them in a thread permanently is absolutely not acceptable. But, back to my story.
I then saw how this person was constantly causing confrontations with this person's daughter. Confrontations that did not need to happen, that treated the teen-ager as a child, that punished the teen-ager unnecessarily. No wonder the teen-ager was acting up! Gently, I talked to my co-worker, and suggested that this co-worker might consider getting help for themself, rather than the daughter, so they could then be a better parent. (Boy, is it hard to write in English without including gender!)
Luckily, this person did not take offense, and I was considerate and diplomatic. But this person also paid no attention to my advice. This person could not see that they were the problem. As long as this parent was part of the problem, they could not cut the knot in half, unravel it, throw the blasted thing away, and heal their relationship with their daughter. So, the drama continues, even today as I write this. So sad and unnecessary.
Alexander got this, you see. He understood that HE was the problem. HE could not untie that knot. But, he COULD cut it in half - so that's what he did. And that's what we're going to do, on this site.
Now, to electronics. There are lots of Gordion Knots in electronics, especially tube electronics. One of these, for example, is "blocking", where one stage is coupled by a capacitor to the next. A loud transient or crescendo can cause a capacitor-coupled stage to "block" (I go into the technical details of this with links later). Now, a lot of engineers have figured out ways to minimize blocking by tweaking the circuit, but keeping the capacitor. Why? Because commercial amps are absolutely driven by cost - and it is a heckuvalot cheaper to capacitor-couple stages to each other!!
But what would be the Alexandrian Solution to blocking? (Alexander's troops referred to his cutting of the Gordion Knot as the "Alexandrian Solution" - they thought it was a HOOT!!) Direct coupling. Get rid of the blasted capacitor!!
Is it necessary for all stages? No, usually just the coupling to the output stage. But some phono preamps are designed to be direct-coupled, and the designers claim that the sound is "faster", "clearer", "cleaner", more "exciting". And they're right. I've built Jeremy Epstein's direct coupled 6C45P (one-stage RIAA) phono preamp, and it is WONDERFUL. I plan to replace the phono stage in the Heathkit AA-151's I mod from now on with his circuit. I'll be posting my way of making his design later, when I start posting projcts. All in good time! But you don't have to wait for me...just go to his link. His direct coupled phono preamp is in the links on the right, just look for the one that says "Jeremy Epstein's 6C45P...etc."
As for getting rid of the coupling capacitor to the output stage, the output tubes? Simple as pie. Use cathode followers, or, better, mosfet followers. Or, even better yet, George's Power Driver mosfet circuit (see the link on the right to George's TubeLab site). Later on, below, I'll give you links to articles and circuits that show how to do this. Is it extra work and expense? Yes, but not much, and which would you rather? Spend an extra couple of hours direct coupling to the output stage, or listen to "blocking" for years and years until you build it over and do it right? If you look inside a McIntosh Amp, some of the best amps ever made, guess what? You'll find the output tubes driven by cathode followers, eliminating blocking. Right there is one of the reasons Mac's were...and are...so good. And you can do the same, piece of cake. Or pie, whichever you like. Or pi, for that matter, since this all started with squaring the circle, which includes the area of a circle, which is .... remember? pi * (radius(squared)). Just kidding.
What are some other Gordion Knots we can cut? Well, as I've already said, we can get rid of the Output Transformer by using mosfets. Or (shudder) transistors. Or even op amps, or chip amps!! For me, rather than trying to become an expert Output Transformer winder, because I really cannot afford really good output iron, and I really don't want to use global Negative Feedback to make up for the shortcomings of lousy output transformers, the "Alexandrian Solution" is just to get rid of the blasted things, and use mosfets. Which is precisely what Pete Millet did with his famous "Starving Student Headphone Amp" (look at the top link on the right, you'll see Pete Millet's site. BUILD THAT HEADPHONE AMP! YOU'LL BE GLAD YOU DID!!)
What's another Gordion Knot? There's lots of them. How about hum from filaments? Well, there are two ways to cut this knot. One "Alexandrian Solution" is to raise the bias on the filament 70 volts positive to the cathode (or, in some cases, 30 volts; see below). That stops the flow of electrons from the filament to the cathode, and very effectively prevents hum from going from the filament (on the electrons, or, rather, with them) to the cathode of the tube.
Whether you choose to raise the filament 30 volts or 70 volts above the cathode depends on several things: how much signal swing the control grid is going to be seeing, and what the filament to cathode voltage rating is. This applies to indirectly heated tubes only, not the old direct heated tubes (DHT's)...(actually, I think when people use the abbreviation they usually mean Direct Heated Triode's, which were the original audio tubes, but there were also direct heated pentodes, as well as direct heated hexodes and so on, so you have to take the context into account to know which meaning is meant if the write doesn't specify)...(DHT's are wonderful, by the way, but biasing the filament respective to the cathode doesn't apply to them).
If the tube is only seeing an input signal of a few volts, or less, such as the input tube for a phono preamp or an intermediate amplification stage in an amplifier, then you can probably bias the filament 70 volts positive to the cathode, so long as the filament to cathode voltage rating is at least +/- 100 volts. If the input signal voltage (peak to peak) is likely to exceed 30 volts, for a tube with a filament to cathode rating of +/- 100 volts, then you're better off biasing the filament 30 volts positive to the cathode, so you don't run the risk of the cathode swing exceeding the filament-to-cathode voltage rating. This is likely to be true for the output tubes, and possibly the driver stage of the output tubes. Now, some tubes have filament to cathode ratings of +/- 200 volts, which can usually be run at 70 volts filament positive to the cathode.
Why 30 volts, historically? Because at one time RCA had almost a monopoly on tubes, and certainly had a monopoly on making the tubes for companies that were using RCA's copywrited circuits...and RCA didn't want to have additional manufacturing costs associated with a filament to cathode voltage rating of greater than +/- 100 volts. RCA didn't make a distinction between input tubes, where the signal peak to peak voltage swing is tiny, and output tubes, where it can be as high as several hundred volts.
However, Tomer, in his classic book on tubes (title later), found that putting the filament 70 volts positive to the cathode has two advantages: it reduces hum (and noise from the filament) more than 30 volts difference will, and it gives the longest tube life - which is very important, in my book. Actually, I think it was more like 68 volts, I'll have to find my Tomer and look it up, and then I'll revise this to give you the precise voltage. If you're going to go to the bother of biasing the filament more than 30 volts, you might as well choose the precise value. I've been in the habit of just using 70 volts, but now that I write this and remember the value was slightly lower, I'll revise my own value for this! Doh!!! (The old saying, if you want to know something really well, teach it, is TRUE, as I just reaffirmed for myself!)
Another solution, which might feel like tying a new knot (!), is to supply the filaments with DC, rather than AC. If you stay with AC, which some audiophiles say make tubes sound better (I don't believe it, and I personally always DC my filaments...all I hear is a black background with incredible detail, so why I'd go to AC I cannot fathom...), but, anyway, if you stay with AC, you have to route the filament wires carefully around the edges of the chassis, keeping them away from any signal wires, especially low-signal wires. Personally, I do both....DC my filaments, and raise them 70 volts (or 30 volts, depending) above the cathode. And route carefully, but I don't have to obsess about it. And I don't have hum in my amps, period. Later, you'll find articles on these topics, along with nice, simple circuits that get the job done just fine.
It's good to keep in mind that while it seemed a simple thing for Alexander to cleave that knot in two, it actually required a really good sword, a strong arm, a mighty swing, a lot of nerve, and good aim. The metallurgy and skilled craftsmanship that went into the making of Alexander's bronze sword was by no means trivial. So, an "Alexandrian Solution" is not necessarily simple....it is, however, elegant...the simplest solution that will WORK. And when I say "work", I mean "work to perfection".
Providing DC to filaments and raising the filaments 70 volts or 30 volts above the cathodes "works to perfection". Giving the filaments AC and having to route the wiring with great care does not. Some amp builders totally disagree with me about this. Fine. You're free to disagree too, it's fine with me. But put your ear up close to a speaker after I've modded a Heathkit AA-151, and tell me what you hear, with the volume all the way up and no signal? Nothing. Put your ear up to the speaker of an amp with AC to the filaments, and what will you hear? Hum. It may be slight, but it's there. You can argue that the music would be so loud that the hum couldn't possibly be a bother...and you're probably right...but you know what? It's still there. The knot remains tied.
MORE TO COME! BACK TO LINKS FOR LEARNING!!
This is a jump ahead, but I want to capture this link here while I have it:
What more could you ask for? A lecture on how to design speaker systems to fit your listening room?? From one of the world's true EXPERTS?? WOWOW
The rest of the series you'll see on the right in a box at You Tube, but start with the link above, so you have foundational understanding for the rest of the series.
1. First and foremost, this forum is run by Max, and he don't allow no crap. This matters. Max stops insults and flame-wars FAST and kicks the offender off. I'm not sure if Max actually deletes the offending email...he may not be able to....but it's an email forum anyway, and hardly anyone ever looks back at old threads, it's all about the new emails in your in-box and the images in the Yahoo folders, so that's a heckuvalot better than forums where every insult is enshrined forever in permanently displayed threads.
2. An amazing, eclectic group of helpful contributors. It might take a while, but even the most arcane question will eventually get you an answer - probably twenty answers, all of them good. I recently decided to make my own PCB's for my auto-grid-bias circuit, because the cost from commercial houses was just too much per board in small quantities, and when I asked for ideas, I got twenty really good answers, with solid advice. Some of them told me which PCB houses to go to for the best price, some of them told me where to go for info on how to make my own, and most important of all, one of them tipped me off to FREE PCB software that works just fine and doesn't take a month to learn how to use. Another member asked about a tube so arcane it's not even in the TDSL...and, after a few head-scratching responses, by gum he finally got an answer pointing him to probably the only place on earth where he might be able to find it.
3. If you're into restoring old radios, this is the place. Period. If you want to make a receiver from scratch, this is also the place. These members know radio, both AM and FM, doesn't matter how old, how busted, or how weird the symptom.
4. A bit weak on tube amps, but that's just because it's still growing and started from a base of radio guys. Max's website (see link above) has great tube amp info and projects on it, and good tube amp projects will be appearing on Fun With Tubes sooner or later, it's just a matter of time. In the meantime, there are plenty of guys there who can point you to a great tube amp project anywhere on the web, so that's almost as good. If you want to ask for help in choosing a project, it helps to specify what type of amp you wish to build. Do you want to make a 1 watt SET? A 20 watt SET? A 25 or 50 watt Push-Pull? A 200 watt monster? A chip-amp? Try to get an idea of what you'd like to make, and I'm sure you'll get some really good answers. Another really, really good approach - if you already have the speakers you know you want to keep a long time - is tell them what speakers you have, and ask for advice on what amp to build to drive those speakers. This is very likely to get you solid-platinum advice.
later, when I have more time to work on this, I'm going to search the Fun With Tubes folders and find some good projects and link them here. I'm sure they are there, but they just have to be looked at.
This is a small forum made up of some of the world experts on tubes and tube amps. It is a great place to browse and lurk, but I would caution you to think long and hard before joining. Frankly, it is a rather close community of only about a dozen, at best, regular contributors, and these guys are perfectly happy having their own little forum and staying within their own paradigms.
This forum has a big plus: you don't have to join to see the links, attachments or posted photos. Which is good, because you should lurk on this one, maybe for a long time.
The biggest problem I have with this forum is that a few of the members - some of them - are not hesitant about insulting you if your post is in opposition to their personal dogma. I mean being downright offensive. So, you ask for help here at your peril. Maybe you get help, maybe you get insulted. They also like to hijack threads - that is, of newbies. This is an especially offensive practice of purposefully going off-topic to wreck whatever thread you're trying to create. Finally, the moderator, while a nice guy and a tube amp expert in his own way, is more concerned with being "one of the guys" than policing the forum, (he said so himself: here's the link: http://geek.scorpiorising.ca/GeeK_ZonE/index.php?topic=3779.0..)...so he is slow to intervene to stop insults, and, what is worse, he does not delete insults. So the insults stay there forever. Not a good place for beginners to post questions, frankly, but a very good forum for learning by lurking and then looking stuff up on google (or a list of links I'm going to create that get you to articles that explain tube electronics really well). It might be a good forum for someone already expert, who can hold their own in a flame-war...if you really want to subject yourself to that. The members who are especially expert, and professional in their conduct, and whose threads you might wish to read - to really learn some stuff, let me tell you - are:
1.Miles Prower. This guy knows tube amps, topologies, screen supplies on pentodes, power supplies, how to use negative feedback, and he knows how to make tubes WORK. He's also a solid contributor who does not insult, and gives outstanding advice and technical explanations. I have great admiration for his expertise, meticulous thinking and professional conduct. Here are some of his threads and projects that are simply superb, some of the world's best (although he does require you to do your own dimensioning (resistor and capacitor values, for example...but, hey, there's no better way to learn than to take a great design and dimension it yourself - what matters is you've been given a great topology by an expert, learning how to dimension it will make you a far better DIY'er:
Miles Prower Thread: The Wolverine:GREAT 845 SET PROJECT: I AM GOING TO BUILD THIS ONE!!! - THIS IS THE BEST 845 TOPOLOGY I'VE SEEN EVER, AND, WHILE IT'S TECHNICALLY DEMANDING AND YOU MUST CREATE A NEGATIVE RAIL, I'LL BET THERE'S A MILLION WAYS TO TWEAK THIS AMP TO GET PERFECTION: http://geek.scorpiorising.ca/GeeK_ZonE/index.php?topic=3866.0
This is a very short article, that will someday be a very long article, when I get a chance to really dig out all the neuroacoustic research.
The engineers argue about numbers, the tweakers argue about sound. Neither side has a pot to piss in.
Here's the deal: First most women, and some men, are genetically incapableof hearing much difference between amps and speakers. Good for them! They can enjoy music and not give a heck about all this audio stuff! Because it just doesn't matter to them. And we shouldn't be beating them over the head about it; let them have their ipods and compressed music and be happy.
No, I'm not being chauvinistic. It's just an observation. If a whole bunch of women want to write me and tell me that audio matters enough to them to spend thousands on really good amps and speakers, I'll change this. All I know is I can count on the fingers of one hand the female members of tube amp forums world-wide, and I know for certain there are hard-wired differences between the neurology of male and female brains. There does appear to be a difference in psychoacoustics for men and women, which I will do a literature search on someday to back up this outrageous statement of mine (it actually comes from reading some psychoacoustic literature somewhere, but I don't remember the source right now...I'll find it.)
Second, for those of us who can hear the difference, nobody yet knows how to measure that difference in a meaningful way that will correlate with the discerning listener's experience.
And here's why: blinded AB comparisons are absolutely MEANINGLESS.
Yeah, that's what I said.Blinding and double-blinding in science isn't always the right way to go. Psychology has known this for decades and decades. More on psychology later; suffice it to say that some of the best psychology tests have been purposefully designed to trick the subject, and blinding had nothing to do with it.
Why? How come do I make such an outrageous statement?
Because we listen with two different parts of our brains: we use one part when we don't know the source of the sound, and we use the other (the one that appreciates critical differences in sound quality from stereo systems) when we DO know the source. I'll explain in detail later. Right now, I just want to plant this startling idea in your head. No, you're not crazy. When you know which amp you're listening to, you CAN hear the difference, you're SUPPOSED to be able to hear the difference. Blinding you only means that the part of your brain that cannot distinguish will be put in control, and thus the blinded test becomes meaningless. So, the objectivists and subjectivists can argue till the cows come home, but they won't get anywhere, because there's no way to prove either right or wrong until we figure out how to do meaningful listening tests without blinding. Tricking? Yes, probably. Blinding? No.
Does linearity in an amp matter? Yes. Do tube harmonics matter? Yes. Both are true at the same time. If they weren't, we'd just all go buy transistor amps at Radio Shack and live happily every after. But you know that's not the case - at least for you.
Criminey, I wish I could get this italics to turn OFF!
I'll eventually get this nailed down, and when I do, I'll put it here, and then we can finally make some sense to all this madness. Until then, have faith in good design, and at the same time trust your ears. And don't let anyone draw a curtain and challenge you to tell the difference - it's like comparing apples and elephants, that's how different it is.
It's no accident that back in the 30's they used to "prove" how good their amps and radios were by drawing a curtain, and then challenging the audience to tell the difference between live music with live musicians on stage versus recordings through the amps or radios. It was a meaningless demonstration, against all common sense - the wrong part of the brain was engaged, and Toscanini himself could not have told the difference.
Here's what I think is going in, in very general terms. Like I said, when I get a chance to really get into the psychoacoustics of this, I'll put it here. But I've studied enough science and scientific literature over the years that I know when something is true...or mostly true. It may not be so simple as I'm about to describe, but I believe the basic principles are correct:
When we were evolving as a species...our closest relative before the apes is this little tree varmint...at some point we evolved two...or at least two...different brain centers for processing auditory information.
One center, probably the first, was for recognizing a sound as dangerous - and instantly triggering the brain into fight, flight or freeze mode. To the extent that we had cognition - cerebral cortex function - we might consciously decide whether to fight, flee like heck, or freeze silently...or perhaps there was even a fourth: play dead.
Have you ever seen a possum play dead? It is the darndest thing. Once, when I was walking in a forest, I heard this tiny little shriek and rustle in the leaves to my side, and when I stopped and looked - I had to look hard, it took a few seconds for me to see the little guy - there, twisted on the leaves, his pink tongue hanging out, was a dead possum. Well, playing dead. I had startled him, he had given his little death shriek, and then had fallen down in a position calculated by him to be as close to dead-looking as possible. It was a dramatic tour de force. (DreamWorks Pictures/Paramount: Over the Hedge: got it almost perfectly right; of course, possums don't walk on two feet and twirl around to fall dead...)
I quietly stood there and watched him, and after a considerable space of time he lifted his head, looked around, got up, and rustled off without a backward glance. To this day I don't know if he actually saw me; perhaps possums are programmed to see movement more than outlines; another thing I'll have to eventually look up!!
Actually, there's a fifth possibility for this brain center, I think: ignore. Not a threat. So, we evolved with this brain center whose job it was to keep us alive by listening - processing incoming auditory information - for threats. It would memorize threats, that's important. It would memorize non-threats, that's also important. But what would it do when it wasn't sure what the source was? Latch onto it, that's what, and not let go until it had it figured out.
If the sound wasn't TOO scary, what would this little brain center, our little protector in the night or in the bush do? It would get us to sneak over and LOOK, that's what it would do. Once we saw what the source was, and decided it wasn't a threat, then our little auditory protector would stick it into the "recognize and ignore" file - or "recognize and EAT" (a sixth category) - freeing that sound up for aesthetic considerations later. And, while I'm here, I can't help but point out the obvious: when our little protector wanted to find out what the source of the unknown sound was, what sense was recruited? Hmmmm??? Sight. Get it?? Blind our little protector, and I'll bet it hangs onto sounds like a pitbull on a bone; ain't none of this gettin' up to the snooty center, the aesthetic center!
OK, you say, well, music is non-threatening, so this lower brain center should leave it alone, pass it up to the higher center that has aesthetic discrimination, right? Ummm, not so fast. When we are listening for differences between audio components, we have an emotional investment in choosing the best one, right? But, if we don't know which source we're listening to, even though we consciously know it is music...and not a threat to life (just our wallet! )....this lower brain center recognizes the emotional involvement - the danger of getting it wrong - and takes over. Heh heh heh. Little dickens. Now, the function of the lower brain center is NOT to distinguish which sounds better - that's the function of the higher center, probably in the cerebral cortex - no, it's function is to IDENTIFY the source of the music. And that's precisely what it's going to do, come heck or high water.
So, a blinded AB test might...might...be useful in you helping yourself to distinguish between sources...but it won't help you in making an aesthetic judgement about which you like better, because the information is being held hostage by the lower center, and the aesthetic center is not being given the information...or the control. Maybe...just maybe...once you've taught yourself to reliably tell which is which while blinded....then maybe you would be better prepared to remove the blinding and make a correct (for yourself) decision on which sounds better (to you).
So, until a good research psychologist wants to play with this, maybe join forces with me, and figure out how to make aesthetic judging of amps and speakers and cartridges, etc, etc, reliable and correlatable to electronic measurements, WITHOUT BLINDING (but tricking is perfectly acceptable, if it tricks the lower center into letting go), I suggest you KNOW what source you're listening to, know the specs of each, and then, putting it all together as best you can, go by Duke Ellington's motto: "If it sounds good, it IS good."
I'll bet if you listened to a good SET amp side by side with a good PP amp, each matched to the right speakers, with the right music for you, and you knew which was playing at each moment, you'd be able to tell which one you like better. (You'd probably like both for different reasons). If you can forget everything you've been told as gospel truth, and just listen....
Your Moment of Zen for the day. Best, Charlie
P.S.: It should sound good sooner and later. Don't get tricked into taking home something that doesn't sound good to you right on the spot, with the assurance from the "expert" that, after you listen to it long enough, you'll like it. Uh Uh. That's accomodation; a subject for another day. Now, is it possible for something to sound good at first, and then not so good as time goes by? Welcome to the world of being an audiophile!! This is a universal experience among those who can discriminate between good sound and bad sound. The longer we listen, the more flaws we hear. The tiny moments of clipping on very short transients we didn't notice at first. The increasingly annoying intermodulation distortion that muddies up the image. The moment of "blocking" when the output stage loses it's bias on a crescendo or big transient and you miss out on the best part of the whole finale. The floppy bass that seemed fine in the show room, but after a month at home, we really miss the clarity of what Ginger was doing so perfectly behind Clapton and Jack Bruce. But this is yet another blog subject for another day; let's just say, now you know a little something to think about.
P.P.S.: Be very afraid of a wall of speakers and a huge master switch in the salesman's hand. First, you don't know which set has been optimized to sound the best THAT day: ("Hey, Mikey, we gotta unload more of these bottom-of-the-line Infinities; set up the amp so they sound grrrreat!!). Second, heck, you don't know for sure which speakers are really on, half the time. Yeah, you can run up and double-check, but that gets old real quick. And annoying as heck to the salesperson, who is about NOT to be your friend. Third, is this the way you'd set up your speakers at home? A wall of speakers is just like cutting holes in your walls at home and sticking the new speakers you just bought into those holes. Right? Think about it. No, you really only have two choices: audition stuff set up perfectly in a dedicated room - either at the dealer or at someone's home - or learn a whole lot about speakers and amp crossovers and amps, and DIY it! Yes, you CAN make your own speakers and figure out how to make them sound fabulous with YOUR system. Sigh...yet another blog. Or just check my links; treasures there. On the other hand, there are tried and true models that are famous for working well with particular setups. Do you have a SET amp, not so many watts? You might want to check out used Klipsch Horns, just find out the right model. I'll put the model's here when I get a chance to look them up. Do you have a medium-power PP amp, with great output transformers? You might just want a set of old AR's, you'd be amazed, especially if you had Rod Elliot's (see links) Crossover Card in your amp and separate Woofers. I once had AR's, I forget the model, it was about 1971(?), back in Backbay Boston, and, until they FRIED my Heathkit Transistor Amplifier (a mad detour into SS land I soon learned to regret...of course, the AR's tendency to have impedance dips at certain frequencies that draw huge current from the amp didn't help), they were simply astonishing.
I also years later goofed with a Sansui Mosfet amp...I know at least one other tube amp builder who made THAT mistake...you could never figure out what was missing, but SOMETHING was definitely missing (a tube!). Someday, maybe I'll try to put a list together of great combo's, amps and speaker combo's that DIY'ers know from their own experience sound darned good. Doesn't guarantee a match for you, but it's a lot better than nothing. I wouldn't take my wife's word (or your's, for that matter, no offense) on the sound of a stereo system on a bet, but when DIY'ers have a consensus on a particular match-up, it's usually the result of good ears hearing good things, with the acoustic aesthetic center of the brain well-engaged.
If you're an electronics geek already...I mean, like an EE or close to that level...then you don't need this advice. Because you already know at least the basics, and whatever question you ask is probably going to be specific and thoughtful.
I built my first tube amp in 1967, but I would never claim to anything like EE knowledge, so I've had to learn everything the hard way, a piece at a time, by...blowing things up (like electrolytic capacitors, that is) ...or frying tubes (hmmm...maybe the data sheet was right!) ....or the frequency response was only 2 KHz to 6 KHz (so THAT'S what qts means....)
But for many of us...who have discovered tubes, the glooooooowwwww of tubes, the sssoooouuunnnddd of tubes....but who only have a smattering of understanding (or none at all)...there's a real chance of making a complete nuisance of yourself, and finding yourself ignored or even insulted on forums. It's no fun, and it doesn't get you what you want...which is your own tube amp, proudly built by you, which fills your house with glorious sound!!
So, here are some rules to follow that I've gleaned from watching various newbies self-destruct and remembering my own blunders over the years
1. Lurk!!!! Learn!!! Just read, read, read, and stay quiet. Follow several forums (I have a list of great ones on the main page on the right side). Over time, you will discover some things:
Some of the members really know stuff, and they will post projects (or have projects at their websites) worth building. Start thinking about which one you might want to build...but don't jump at it...you'll be amazed at how that first project you thought was soooo great doesn't really suit your needs. You don't really want to fill the center of your living room with an amp spread out on plywood you have to walk around to the other side of the room to work on - and which, if the cat ever wanders into the center of, is likely to cause domestic discontent as you try to explain to your loverly/handsomerly other how the cat turned into a smoking, blackened, greatly puffed-up carbon-filament fuzz-ball, and why it no longer moves or makes hungry noises.
I will be posting a category of projects worth building, culled from the net. Amps and speakers that look to me like really good work, something you could build and really enjoy.
2. Try to resist the impulse to join right up, and say Hi!! to everyone, and tell about your Uncle that was a Ham, etc., etc. Sorry, tube amps are actually serious stuff, and the old members of the forum - most of whom are serious electronics geeks - don't give a rat's behind. If you want friends, join AOL (I guess, I wouldn't know) or maybe a band groupie-club. If you want to make a great tube amp, pay attention to the masters and leave Uncle out of it. Now, it's true that you may wish to join in order to view images and schematics that may not be available to you as a visitor. That's OK. Just don't announce it. Nobody cares. Sorry. I really am. Oh, the founder of the forum might care, it's ego-building to get a new member, and founders of forums don't usually get much thanks and certainly no payment (except for the forum of an amp builder who sold you an amp, but this is DIY-land we're talking), so you'll get a welcome from the founder and a few others, but....well, take it with a grain of salt, that's all I can say.
3. Start to notice who's nasty and who's nice. And who's just a nut blatting away on a one-note trumpet. This will be good to know later when you finally decide to post; think about whether you really want to post in a topic dominated by a nasty (doesn't have to be the moderator) or a nut. Insults hurt. Flame wars really hurt; if the nasty is a board-member, you will lose the flame war (not that there is ever really a winner in a flame war). And then there are "pig-piles", too, which you don't want to find yourself at the bottom of. And all of that is on the web forever. All the forums claim to forbid such nasty behavior, but good intentions and actually enforcing it are two different things. And even when a moderator steps in, I've noticed that the insults don't always get deleted or moved. So, they stay there...forever.
4. Corollary to #3: I've noticed that, all in all, the better projects seem to belong to the nice guys. The nasties do stuff, yes, but their stuff tends to be a little quirky or....off... "Their way or the highway" kind of thing. Which doesn't mean that they're right. Just close-minded. And if you post something that doesn't agree with their view of the world, get ready to be insulted.
5. GOOGLE is your friend. (unless you live in China....sorry) Try really hard to use google to answer most of your own questions. Don't barrage the forum members with dumb questions. Look it up! Figure it out! Forum members do NOT get paid to answer dumb questions...SORRY!! They do get tired of explaining, for the thousandth time, what size bypass capacitor is needed for the cathode resistor. Some forums DO have the motto: there's no such thing as a dumb question...and that's a really good thing...but after the twentieth dumb question you might find their responses a little...ummm...tepid, shall we say? Now, if I had a forum...which I probably never will, but who knows...I would create a way of easily directing simple questions to FAQ answers. If there is one already somewhere, I'll gladly link it. Someday maybe I'll make one up myself.But I know that using FAQ lists are a royal pain, nobody likes them, so a friendly directive would be nice: "Great question, everybody has to learn how to figure that out to design a tube amp; go to this link: cathoderesistorbypasscap/FAQ/HTML. If you need more info after reading it, please feel free to ask." Now, once you've done your research, and you're still stumped, or have popped up to a higher level and have a more sophisticated question, that's different - explain briefly what you've read - a few links are a good thing - and ask what's puzzling you. You'll get lots of friendly help, because you tried.
6. Resist the impulse to post a project one step at a time, as you go. There might be exceptions, like building someone's project, and showing your progress, and maybe posting when you get stuck and need something clarified. But posting as you go, complete with mistakes, backtracks, changes, detours...this is one I've been guilty of, so I know...if you take it too far, everybody just gives up on it. What people like: when you've done all the hard work, and have a nice result, and can explain why it works. There, in black and white. What nice guys will be glad to help you with: when you've done hard work, but get stumped, and need a little help. No problem. Geeks love to solve problems...that is, real problems. There's a big difference between the problem of blissfully ignorant - where you haven't done any homework at all, that is, real bench-work - and the problem of a technical challenge you've come up against after putting honest work in.
7. Be careful where you wander....make sure you're still on the DIY part of the forum, not an associated COMMERCIAL FORUM FOR A MANUFACTUROR'S PRODUCT....this is especially true at audio asylum (see list of forums). Once, enough years ago I'm not embarrassed about it anymore, I was trying to get the answer to a simple technical question - I forget, it was probably really a DUMB QUESTION - on Audio Asylum, before I knew better. Somebody made the innocent suggestion - maybe, in retrospect, it wasn't so innocent - that I pop it over to one of the MANUFACTURERS FORUMS. Wow, was that a mistake! I got tarred, feathered, burnt up by a flame-thrower, and they were getting read to ride me out of town on a rail when I realized they had completely misunderstood...or maybe not ...and I got the heck out of there, never to return. So that's why I'll never link to that commercial site or it's forum. Now, the owner may be the nicest guy in the world, but I'll never know. All I know is I got a very rude reception, I guess from "his posse", and will never go back. Which could be unfair to him, but criminey, all I did was ask one simple question....but if you wander in there without first buying one of his amps, don't say I didn't warn you........does the same apply to other MANUFACTURERS FORUMS? Well, at the very least it is NAIVE (maybe even rude) to ask a newbie question in a commercial forum you didn't buy a product from, but on the other hand, it IS a chance for a manufacturer to get you as a customer...so I guess it just depends. My advice, unless you're seriously considering buying one of their products and have a specific question about IT, is DON'T.
8. Now, this is a toughie. Try really hard not to think you're going to invent some new circuit that's going to knock everyone dead, right off the bat. Trust me, it's all been done before. Well, almost. The only recent patent I think is worth a fart is one of Nelson Pass's. Most recent amp patents are boooolsheeet. I love it when Broskie (tubecad) makes mincemeat out of some "new" patent. I think it's really important to keep in mind that those guys back in the 1920's and 30's and 40's and 50's were SMART. (which is a good thing!!) Just about every possible way a tube - and it's grids - can be used has been tried. Uh, decades ago. So, learn, learn, learn, (go to Steve Bench's site, which I pray never disappears from the web...OOPS, it's gone! Thank you very much, AOL.), build something good that's already been done, and listen. Don't even think about trying to do original designs without an oscilloscope and a distortion analyzer - because how are you going to figure out how to optomize the design, and how are you going to post the design and back up your claim that it sounds good?
Tube amp understanding has come a long way, and freaky designs without good measuring really don't deserve much attention. Is there still room for improvement, for new ideas, for new tweaks? Yes, absolutely, I'm just giving you a little friendly advice that true improvements in amp design don't come easy - it takes a lot of hard work and time - it took me years of getting back into tube amps and really working hard at it before I started to have an understanding of where real improvements in design could even be attempted, much less figure out how to get that improvement.
For example, I'm getting close to having a finished PCB board design for an auto-grid-bias board for push-pull output tubes that keeps them in balance - almost perfect balance - that keeps them in Class A as long as possible but allows temporary excursions into AB - that prevents runaway tubes ("cherry" tubes) even if the output is dead-shorted - but, you know what? (I'll tell you what....twice, actually):
First, it took me a year to develop this circuit. Of course, part-time, mostly stolen hours on the weekend from chores I was supposed to be doing but, second...
It wasn't really a new idea. As John Broskie pointed out in a tubecad blog entry: http://www.tubecad.com/2005/May/blog0046.htm Alfred Blumlein invented a push-pull balancing circuit in the early 1930's (the "garter" method) which was, using what was available to him at the time, pretty good....
And my circuit is actually based on a circuit Broskie posted in the same blog...I took one element from his circuit, using an op amp integrator with a 1-second RC constant, and then developed my own from that, complete with my own bells and whistles (such as the protection against runaway mode even with output shorts, etc.)...
But I wouldn't claim my circuit was at all an original idea (for Heaven's sake, I'm using op amps!! - "transistors for dummies"), it's just my implementation of an eighty year old idea from my own perspective. That's all. No biggie. And it took a ton of reading everything I could on the web and in print about tube electronics (and op amps) before I was able to put it together. I actually call it the Broskie / Knouse Auto-Grid-Bias Circuit, because without that one essential building-block idea from Broskie, I would never have thought it up.
When I get the new PCB's and build and test a bunch, and all turns out well (it works great on the prototype board, but converting to PCB is always a nail-biter ), then I'll send some finished ones to Broskie and ask his permission to include his name.
So, thanks for reading, I hope this has either entertained you or helped you. If you have suggestions for additions to the list of ways to be a good forum member, I'd love to hear them - as soon as I figure out how to enable the contact part of this blog thingie, that is...
(It only took a year and a half and I had to disappoint a whole bunch of people...but between using Allen Wright's single-ended design for the phono preamp section, getting rid of the global negative feedback, getting rid of an entirely unnecessary amp stage in the old Williamson design, doubling up the output EL-84's for much more power with less distortion and far better damping factor, and moving the power supply back outside of the amp (which enables doubling the output tubes), I think I've finally got the final design. No more remote control; that turned into just far too much hassle and expense and complexity...maybe someday.
(I will be posting soon, though, on some interesting experiments with different ways of making variable inductors and capacitors that I've not seen in classic (or modern) designs...
Note: all the links are listed on the right, grouped as best I can. COMING: all the same links organized into folders on the LEFT side of the page.And, there is a third purpose for this site: mods to Heathkit AA-151 amps, a place I can document ways to improve the old amps. If you have suggestions, please feel free to send them, I think I have all the comments links at the end of the articles working now...comments have to go through me. I'm easy to get along with, and I like different perspectives and ideas, so please don't be put off by the security of the link...it's just to stop spammers.
...and which will transform them (heh, get it? transform?) from 14 watts per channel to .... oh .... hundreds of watts per channel....or pretty much as many watts as you want. Want a thousand watts per channel?....this can be done heh heh heh.... 
For a thousand watts per channel you'll have to spend a hundred bucks per channel on mosfets, but you can't even get output transformers for such an amp - maybe from Sowter, who can probably make just about anything, given enough money - but your only other choice would be to put ten of the biggest Hammonds in parallel. Which would be nuts. 
(I actually really LIKE Taylor Hicks. The rest I could live happily without....
). The link to his website is in the list of favorite links on the right side of this page; just look for Guido's Site.
....I'll explain the Legend of the Gordion Knot, and what it means for helping each DIY'er come to peace with what they want to achieve, tomorrow...
...or frying tubes (hmmm...maybe the data sheet was right!) 
Sorry, tube amps are actually serious stuff, and the old members of the forum - most of whom are serious electronics geeks - don't give a rat's behind. If you want friends, join AOL (I guess, I wouldn't know) or maybe a band groupie-club. If you want to make a great tube amp, pay attention to the masters and leave Uncle out of it. Now, it's true that you may wish to join in order to view images and schematics that may not be available to you as a visitor. That's OK. Just don't announce it. Nobody cares. 
Try really hard not to think you're going to invent some new circuit that's going to knock everyone dead, right off the bat. Trust me, it's all been done before. Well, almost. The only recent patent I think is worth a fart is one of Nelson Pass's. Most recent amp patents are boooolsheeet. I love it when Broskie (tubecad) makes mincemeat out of some "new" patent. 
