The Op Amp Big Muff has all the hi-gain, saturated goodness that fans have tried to emulate for almost 25 years. With the 3 classic controls you'd expect to find on most Big Muffs (Sustain, Tone and Volume), you can carefully craft your optimal fuzz sound. Rolling in more top-end cut the higher you turn it up, you can also bring in some sub-octave warmth when you set it lower.