The Electro Harmonix Op-Amp Big Muff is a reissue of a classic fuzz pedal from the 1970s. It aims to give you the iconic and sustaining distortion of that era. Three main controls are at your disposal including a volume knob for overall level, a tone knob to shape your timbre, and of course the fuzz knob with which you can introduce sweet distortion into your signal.

The original pedal relied on op-amps rather than transistors to achieve its signature, needling timbre. This pedal aims to recreate that original V4 circuit as faithfully as possible even as it adds a couple of tweaks to the design. For instance, the tone switch, which takes the tone knob out of the circuit altogether, no longer affects your overall output level. This is a departure from earlier iterations.

The Op-Amp Big Muff Pi utilizes true bypass circuitry, to keep your tone pristine when it is bypassed. The pedal ships with a 9V battery, which can be replaced by unscrewing the backplate and accessing the battery therein. It also works with a 9V AC power adapter, which is available separately.