The Electro-Harmonix Percolator fuzz pedal revisits the rare Interfax HP-1 Harmonic Percolator circuit with expanded control and modern functionality. Inspired by a cult-classic design from a Milwaukee audio repair shop in the 1970s, the Percolator delivers everything from raw transistor-style overdrive to gated fuzz textures. Built around asymmetrical clipping that emphasizes even-order harmonics, this EHX pedal responds dynamically to picking attack and guitar volume changes while producing a wide range of harmonic textures and fuzz responses.
From Transistor Drive to Gated Fuzz
The Percolator's core sound ranges from chewy, crunchy overdrive to ripping, Velcro-style fuzz. The Harmonic control adjusts gain at the input stage, allowing players to move from dynamic low-gain drive into saturated fuzz textures. Its asymmetrical clipping circuit creates a distinctive harmonic character with enhanced even-order harmonics, giving notes added complexity while retaining touch-sensitive response.
Bias Control and Dual Drive/Fuzz Modes
A powerful Bias control allows players to shape the response of the gain circuit, introducing everything from smooth sustain to pseudo-octave tones and heavily gated fuzz textures. The Drive/Fuzz toggle changes the pedal’s character by disengaging or engaging the clipping diodes. In Drive mode, the pedal behaves more like a raw transistor overdrive with organic attack and gritty breakup. Switching to Fuzz mode activates the clipping diodes for heavier fuzz tones with increased saturation and harmonic complexity.
Modern Features With Vintage-Inspired Character
Beyond its versatile controls, the EHX Percolator includes an internal trim pot that can enhance sub-octave content while adding additional gain and low-end rumble to the circuit. A mechanical relay true bypass system preserves your clean tone when disengaged, while the footswitch supports both latching and momentary operation for instant bursts of fuzz during performance. Powered by either the included 9V battery or an optional power supply, the Electro-Harmonix Percolator fuzz pedal delivers modern control over one of fuzz history’s most distinctive circuit concepts.