Electro Harmonix Op-Amp Big Muff Pi Distortion/Sustainer Guitar Effects Pedal

Mike Matthews has brought the legendary Op-Amp Big Muff back from the realm of collector’s items to the hands of working musicians everywhere. Originally commanding sky-high prices on the vintage market, this late-70s classic has been faithfully reissued with the exact same circuitry that made it famous, now housed in a practical die-cast chassis with true bypass switching.

The Op-Amp Big Muff earned its stripes through Billy Corgan’s masterful use on Smashing Pumpkins’ groundbreaking 1993 album Siamese Dream. After testing the reissue, Corgan himself confirmed that “The magic’s still in the box, I can still get what I’m looking for!” — a testament to the pedal’s authentic recreation.

What sets this Big Muff apart is its unique architecture: op-amps instead of transistors and three gain stages rather than the typical four. Big Muff historian Kit Rae describes the resulting tone as “a huge, crushing Big Muff sound with more crunch… great for grungy, wall-of-sound distortion, heavy rhythm playing and heavy leads.” This is the IC or V4 Big Muff that shaped an era of alternative rock.