The Electro-Harmonix Op-Amp Big Muff Pi (Version 4) is a distinctive chapter in Big Muff history, replacing the traditional transistor stages with op-amps for a sharper, more aggressive fuzz character. Known for its biting attack, focused midrange, and raw sustain, it delivers a grittier, more cutting tone than earlier Triangle and Ram’s Head versions. Made in the late ’70s during EHX’s New York era, this version became iconic decades later for its punchy, snarling sound that slices through a mix while still retaining classic Big Muff saturation.
The pots on this unit date it to 1977. Supposedly, only a few thousand of these original V4 op‑amp Big Muffs were made, which contributes to their rarity and desirability among collectors.