Hi. I am handy with a soldering iron but less so with circuits and diagnosis. I would appreciate any suggestions here, and I hope i'm in the right forum.

I have a black russian big muff, and recently had it true bypassed.
The unit causes an unlawful hum either either bypassed or engaged.
It only allows signal when I engage the effect, and even then I can only hear the distortion below the hum.
When I bypass the effect, I lose all sound but this crazy hum.

I've opened her up, and I don't see anything visually suspect. The battery is fresh and the ground wire is screwed one of the feet on the back of the effect casing.

Is this likely a problem with the footswitch?
If a component on the board were blown, would there be sound at all?


If I plug the cables in backward, I get a standard bypass sound, until I engage the effect, and the pedal is muted.

alright,
I'll leave it with you all.
and
Thankyou

You may have the switch wired wrong. What bypass scheme did you use? Can you post pics?

The true bypassing was not done by me, however it had worked fine for the last while since I've had it again. I connected the pedal to my setup this morning, this time without battery. I get a very weak guitar signal, dominated by the much louder hum.

All the switch wires appear intact.

Thanks for taking a look.