I feel pretty stupid telling you this because you probably already know..but just in case..the Big Muff (Russian made anyway) plugs in backwards as opposed to any other pedal..when you plug it in the wrong way, all you get is nasty ass feedback..Like I said..you probably already knew this. If that’s not the case, your circuit board is fried..but the strange thing is, is that it really takes alot to destroy these bad boys..I’ve played mine at numerous live shows..it’s been tossed around..ragged on..beaten..beer poured all over it..kicked..and it still throws down some mean ass fuzz..hmm? Kinda like a bar scrub..?