Gristleizer

The Gristleizer is a circuit by Roy Gwinn dated back in 1975 and combines a tremolo with an oscillator-controlled filter. The most famous user was probably Chris Carter from Throbbing Gristle. It has a considerable versatility, allowing you to achieve sounds from polite, smooth tremolo and auto-filter wah wah sounds, to industrial grinding distortion, ring modulation, and hard stuttering effects

You’ll find the schematic here.