#1
Do the 4 Big Muffs all have different sound, or is it all the same?
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#2
As far as I know there are:
1. The Original (aka made in American) Big Muff Pi
2. The Little Big Muff
3. The Double Muff
4. The Metal Muff
5. The Russian Big Muff Pi

The American and little Big muff are relatively the same pedal, but the little muff has the size of a boss pedal. The double muff, from what ive HEARD, is too much muff (hehe), and as a result sounds worse. The metal muff, again, from what ive heard, is really good. I feel that the original muff is enough for me, but some have a need for bigger and more elaborate muffs (It has equalizers). The russian has less of a full tone, although some prefer it.
#4
Russian Big Muff gives your sound more punch - thats my impression
You should test them yourself!
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#6
I've tried a Metal Muff. IMO it pwns most other "metal" pedals. You can EQ it to do just about anything. But the "top boost" to me is useless unless the knob is under something like 3. Anything over that adds too much treble.
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