Harmonic Percolator

The Harmonic Percolator is an exact clone of the cult 1970s Interfax Harmonic Percolator, the oddball overdrive/distortion popularised by Steve Albini. Fredric Effects builds it from a verified schematic using period-correct parts: a 2N404 germanium and 2N3565 silicon transistor pair with 1N695 diodes. Rotary pots replace the original sliders, and a switch offers three clipping options for varying degrees of asymmetric grit. The result is a harmonically rich, slightly broken distortion that reacts strongly to guitar volume and pickup choice. Handmade in the UK.