True bypass volume drop mod

[stoneattic]

I have a Crybaby GCB-95 from around the mid-eighties that I converted to true bypass and added a rotary switch to change caps and well as convert it to a volume pedal. The problem is when I turn it on there's a little bit of a volume drop. I've found plenty of references to lowering the input resistor from 68k to 47k (or so) but all of them show a different PCB. On top of that none of the resistors on my board appear to be 68k. Here's my board:



Higher res pic here: http://stoneattic.homelinux.com/public/wah/board_sm.jpg

Has anyone seen this layout and know which is the resistor to change? The resistor I believe is the correct one is a 390. I bought mine new so I know there are no mods besides the ones I listed above.

thanks!

[petemoore]

Schematic...
IIRC the 68k is the first resistor after the input cap.
You can try smaller values by using clipwires and resistors...
Grab a 68k and see what values build when paralleling various resistors, two 68k's parallel is 34k, or use say a 100k pot parallel to find the resistance to build on the 68k which allows the volume and sound you want.
Type 'wah mods' into google and see if you can find Paul Morassy's page.