FKR - FOUR KNOB RAT

The Proco Rat is probably one of my all-time favorite pedals. Nothing comes close, as far as I'm concerned, to the raunchy irreverent growl that comes out of that box. A few months ago I built a Rat clone and started studying the circuit. What I discovered is that the Rat topology is an ideal laboratory for mods. It uses a cheap nasty LM308 opamp with a pathetic slew rate, and bog-standard 1n914 diodes that clip the output. So why does it sound so good? I think a combination of things like the interesting feedback loop to ground and the fact that the LM308 adds a lot of its own clipping.