OD section problem

[mbeldyga]

Hi.

I've got strange problem with OD section in my dumble inspired build. When I turn normal and OD gain pots all the way up and normal and OD master leave at "0" i can still hear guitar sound form speaker.

I thought it was bad relay, so i replaced it (it's wired as shown in #124 thread). Then i've changed wires pot<-->circuit board which weren't already shielded to shielded. It didn't help neither.

I've got another gain stage (with potentiometer wired like master volume) after send/return sockets in the back, but before PI, something like two-rock does in their amps.

Any suggestions? There must be some signal leakage somewhere, but i can't spot it.

[llemtt]

your leakage origins from V2b stage before the OD master, most likely from plate resistor or coupling cap

then the signal reenters somewhere in your "additional" (recovery?) stage

it's not easy to design such a layout with an additional gain stage before PI which avoids those problems completely (HAD had many good reasons to put the effect loop buffer outside the chassis...)

anyway small leakage doesn't hurt your sound so you can ignore it

cheers
teo