Re: TRACED...Zvex Fuzzolo. But I need help with verification.

Posted by nocentelli on May 23, 2015; 7:22am
URL: http://guitar-fx-layouts.238.s1.nabble.com/TRACED-Zvex-Fuzzolo-But-I-need-help-with-verification-tp20721p20737.html

I think C6 is probably correct as drawn, though R10 may well be bigger (10k would make more sense). Here's my reasoning: In the mammoth, the parallel 10n cap is part of the tonestack, and accentuates the treble when the tone pot is over to the bright side. In the fuzzolo, there is no tonestack but there is that 20k to ground: I'm guessing it is there to reduce the level and act as a HPF to lower the bass content before the signal hits the mosfet - this will be more effective if R10 was 10k (R10 and R9 acting as the two resistances in a voltage divider volume pot set to "2/3 volume"). If C6 was in parallel with C5 and R10, there would be no DC blocking cap in front of the mosfet gate: This would put a 20.1k or 30k (if R10 is 10k) resistance to ground in parallel with R13, and would mess up the biasing of the mosfet gate.

If C6 is indeed drawn correctly as I suspect, 100n makes more sense than 10n which would thin out the bass a bit too much. It's on the breadboard now, and I'll try it out with a 10k R10 this afternoon.

Thanks for all your efforts to trace this!