How to create a distortion effect circuit using op-amps and RC filters. Includes schematics and discussion of power supply biasing.

Mini Space Rockers is a simple percussion synthesizer; the site offers complete circuit diagrams and parts lists.

Pink noise generator using two op-amps, requires +5 and -5v power.

Attack/release envelope generator circuit, designed for +12 volts. Still looking for a zero-attack/immediate-decay envelope circuit… maybe the decay portion of drum trigger circuit will do the trick. There’s also 555 timer based ADSR; I don’t quite understand how it works, but it looks pretty simple and doesn’t need many external components. It wants +/- 15V supply, which is awkward, but perhaps I can make it work on 9V by reducing all those 4.7k resistors.