#1
It won't work on, i'll hit the bypass, and my amp refuses to make noise, but when I hit the bypass again to have it off, I can hear my amps natural clean and distortion.
Yes, I have it plugged into the correct battery eliminator, and there is a fresh 9V in, but either way it won't work.

It was working fine like a week ago.
#2
are the you plugged into the right input/output?

my Fulldrive did that, i plugged my guitar into the output and it didnt make any noise when on, but did when bypassed.
Ibanez AFS75/Fender Strat Plus > Fulltone Deja' Vibe > Keeley TS808 MOD+ > Fulltone OCD > VanAmps SoleMate > Metro JTM45
#4
Sounds like another faulty Metal Muff. The demo Metal Muff we got did the exact same thing within a few days.
#7
Could be something simple.
If your not under warrenty and your decent enough with some tools, have a look inside it.
It could be just a soldered joint come undone.
My Gear:
Jackson RR3 + Bill Lawrence L500XL

Sennheiser EW500 Wireless
T-bone EWS wireless
IbanezTS9
MXR 6Band EQ
Ibanez WD7
Decimator

Peavey VK100
Epiphone ValveJunior
Kustom Quad100DFX 2x12
MicroCube!
Marshall 1960A 4 x 12