Hi,

I’m having a problem with an old Russian Big Muff. I’ve done some modding to it.
I’ve added the mid control pot, I did the resistor mod where I changed R8 and R13 to 18k resistors.
I also changed the switch because I thought it was broken, but apparently it wasn’t.
I did a true bypass wiring with the help of the diagram that has been posted here multiple times.

First question:
In the old switch there was a wire coming from the sustain pot. Is it supposed to be left out when doing the true bypass wiring with a standard dpdt switch?

and the main problem:
After my modifications the volume and sustain pots work pretty much as they are supposed to, but the mid control I added doesn’t work at all and the tone pot only turns the sound into very thin fuzzlike sound. I had all the pots working for a short while, put there were some contact problems or something (don’t know the correct word) and it made awful cracking noises. Then the mid control died and the tone pot does what it does. I’ve double checked and triple checked all the connections and my solder work, but I’m all out of ideas because I’m still a noob with these things.
So if anyone has any ideas how to fix this, I’d really appreciate it.