Were you trying to measure voltages without a tube in place? That generally doesn't work on this design.

Hmmn, I used to get updates when people posted to this ancient thread, but not any more.   I'm not sure where you're measuring 24VDC at, so it's hard to guess what's wrong. You don't have the LM317s in backwards or something, do you? Did you include the LED? Are you measuring with the tube...

Quote: Like was noted above, take the specs with a grain of salt. It also runs (quite) happily from higher voltages; a lot of people built 'em with 32V or even slightly higher PSUs. (I have, um, four of these amps, or variations thereof.)   There's a really, really long thread about...

Quote:   Ah, the residentially-disadvantaged; what sweet music they make. :)   I save a certain bit of scorn and loathing for the term "airy", myself.    

Should you ever contemplate self-publishing a novel, I've learned the hard way that the sad truth of the matter is that the ability to write an entertaining story has no effect on your (success or) failure. It's 98% blatant lie-filled self-promotion, and 2% luck.   Last July, I published a...

The hum sounds like a grounding issue, but troubleshooting that can be "fun".  As to imbalance - this can often be due to the tube used, though djusting the trimpots may or may not help. This is where it helps to have multiple tubes to play with - the odds of two tubes being identically...

Just remember, if it was easy, anyone could do it. Don't worry, though - it's definitely worth the wait.        

"Tightly integrated" as in it's designed to be used with some certain, specific parts, board-mounted, in one of a few select enclosures. Depending on your attitude, this may or may not really be a feature. (I consider it a flaw, but YMMV considerably.)

Cmoy: about as basic an amplifier as can be made, though rarely made well. Mini3: tightly-integrated portable-only Cmoy-esque design with active ground, no coupling caps, and built-in 9V charger and battery. A47: Buffered CMoy. Mostly overlooked these days by people whose guru told them...

Boosting USB 5VDC to a more "desirable" voltage works just fine. People don't like it around here because:   1, none of the DIY audio cult leaders have ever done it; and 2, most people have completely irrational prejudices against both computer power and switchmode power supplies.  ...

I've used mine extensively with ATH-M30s (65ohms), and to a much lesser extent with RP-HTX7s (40ohms), some severely ancient ATH-5s (??ohms) and even some cheap old Koss UR-19s (32ohms), and have encountered no problems. Sorry, just not cool enough for high-impedance 'phones, I guess.   They...

They'll still work. You can (almost) always make physically-smaller parts work; the opposite is usually not the case.

Yep, the 6N23P will work just fine; I have a couple in amid my "hopefully lifetime supply of relatively inexpensive tubes".

An improvement, though I can't imagine C1 can pass DRC like that. You could probably move it and the power terminal to the lower part of the board, and save half a square inch per copy, or thereabouts.   If you post the .sch file, people can probably take a crack at creating a more optimized...

Good point. Well,it'll go away so long as he rips it up before he creates the ground plane, anyway. (I don't think vias automagically merge into plane pours. Might be wrong; haven't made anything with a via in many months.)   I'd still move the power connector and capacitors around, to...

On V2, move C2, and you can re-draw the traces such that everything is single-sided, or you can have all the signal traces on one side and a ground plane on the other. Move C1 and the power connector too, and you can shave 10-20% off the size of the board. If not, at least get rid of the vias...

The 6DJ8 amp not only has a plethora of inexpensive and readily-available tubes, but, if you use IRF510s for the output devices, *every* part needed (including the tubes, natch) is still in production, and pretty easily available, globally. IMO that should count for... something.

That should work fine, though the Legion Of Very Anal Linear PSU Fanbois have some dogma-filled tracts they'll probably be sharing with you shortly on the many sinful and wicked moral and psycho-electrical shortcomings of a SMPS like that. I suggest you tell them where to stick their $75...

Odds are they will have no meaningful effect, given that the LM317s are little more than constant-current sources for the tube heaters, a not-terribly-demanding application by almost anyone's standards. But, in the spirit of pseudoscientific inquiry, given that tantalum caps are only around $1...

Yeah, you want the through-hole TO-220 IRF510, not the SMD version. Don't worry, we've all done that.   And yes, those 2SK117s will do just fine.

The circuit, as far as I can tell (I haven't checked every resistor...), is identical, save for the lack of input caps, and the addition of a tiny tantalum cap on each channel between the drain of BG201/BG202 and ground. On mine they aren't marked. What purpose they serve, I'm not 100% sure...

GT20V:   1. In theory, maybe. In reality, it's not quite that simple, as, among other things, DC offset can become an issue. As far as I can tell they were omitted to save space and money, not for any dubious sonic improvement.   2. You certainly can change the output caps (I've done...

I suspect that the "quality" of C103 (i.e. low ESR) has a certain effect, but no amount of "quality" will compensate, as far as I can tell, for too-low capacitance.   Can't help you on a switched pot, as I never use 'em. As far as I'm concerned, the fact that the amp runs (by default) on...

Oy, is this thread still alive? Amazing! Quote:   It was convincingly (i.e. math was involved) argued somewhere that C102/C202 should be 1000uF, I think. It's not too hard to find suitable caps, so I tend to err on the side of caution there, per (dBel's?) advice.   The discussions of...

So, this isn't strictly audio-related, but hear me out.   I've gotten sick of having a gajillion wall-warts attached to things attached to or just around my PC, so I've decided to build a tiny little power distribution unit that'll take a laptop power supply in on one side (15VDC @ 6A) and...