Train Express 6V6 completed. This build uses Vishay coupling caps, Nichicon power caps, Hamond 372DX PT, Hamond 1760H OT, DIY drilling on a blank JTM chassis. I have the tubes biased for 8.5 Watts. One change on the AAE layout is grid bias uses 50V tab, so R30/R31/P1 changed to 39k/30k/10k. I am still waiting for the second coupling cap on V2 (C5 2200pf), but fired up an playing anyway.
Grounding is good and there is no hum. However as I turn it up I am getting a sound like the shower is on - basically white noise and static. No noise with the volume all the way down, so either in V1 A/B or the tone stack. It occurs with or without the input connected. I have checked the pots, by replacing the volume and disconnecting the tone stack ground. I am suspicious of the unused V2B, should I ground the cathode or remove the heater on 5?
One other weird thing is when I change my volume on the guitar it is supper scrachy, and changing pickups makes a loud pop. This happened for two different guitars on this amp, and both guitars are fine through other amps. Any idea what this would be?
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The white noise issue is fixed, I replaced both the V1 plate resistors with 3 watt and replaced V1 with a 12Au7. These changes don't make sense as I tried another 12Au7 and several 12Ax7s earlier. I did notice that with the 12Au7 the voltage drop over the 3 watts resistors (R4 and R6 I think) was really high, like 100-175V. Maybe I was high because that seems weird too.
The other thing I did, which seems to be the more likely solution, is checked the ground on all my power caps. I am thinking that maybe one of the ground leads was touching the outer casing on one of the caps. Checking each cap's ground elevated it off the board a bit. Probably not a good idea to use radial lead caps on an axial mount board! I really dig these Nichicon caps, so no regrets.
New tubes came in the next day. Once the build is stable I put in good tubes. I am running Tungsol 12Ax7 and 6V6GT. The white noise did not come back. I have the 6V6 biased at 9.5 Watts which may be a little hot. The problem now is that with the new tubes I cant turn it up past 8 o'clock (6 o'clock is zero volume). I may go back to the 12Au7 in V1, where I could get it up to OD levels without being painfully loud. This configuration works well with pedals up front, as they push it to OD.
Over all this amp is transparent to what you put into it. Switching pups, setting the volume on the guitar, boost pedals, different guitars, all cut through with their own unique sound. This amp does not make everything sound like the amp, each thing sounds like itself. Except really loud and painfully clear. If you don't like how you sound through this amp then the problem is you.