ilovefuzz.com

I found this on the internets. I dont always repost schematics, but when I do, I drink dos-equis

its a 12Db/octave low pass filter that can run on +5v or +9v. stick it in a pedal. add it to pedal on the input or output. use it in a noise maker. I think its optimized for line level or modular high voltages. anyone that tries it first should report back the results. a transistor substitute may be required for pedal use. if you can figure out a way to make it work on one pot instead of the double pot that would be helpful. and I want to omit the resonance knob but I dont know where to stick the resonance resistor for no resonance.

Resonance rocks though! But try replacing the pot with a 10k resistor, and connect what used to be the 'wiper' to one end of it, then the other. One end will howl like a demon when you adjust the cut-off, the other should be a more gentle sound.

The double pot... hmmm, they're a pain. Basically it's two lo-pass RC filters in series, I guess for a stronger effect. You could get rid of it completely, and have a 100k with a 100nF going off to earth, then the same pair again, and THEN put a (single) pot before them that sends the signal either through the two RCs or bypasses them completely... or some inbetween mix.

Lo-pass filters that actually do something can be a bit temperamental, I've found. I got my Compactotron working well in the end, but after months of unwanted oscillation. See http://www.raingerfx.com/compactotron%20c-2.html

Wouldn't mind giving your circuit a go though.

Actually, my double pot fix won't work - it'll just fade between lo-pass and no lo-pass, it won't actually alter the cut-off frequency, which is what the dual pot does.
Have to think a bit more about that one...