Circuit Audio Sound Effects
The gain is dependent on the setting of P1 and the chosen effect degree. It is between 10dB and 30dB.
Set the input level with P1 until the VU meter points between 40 and 75% when a guitar string is struck. Select the distorsion level with P2 from 0% to 100%. You can now select the waveform with P3.
Opamp A1 is an impedance converter and signal buffer. Opamp A3 amplifies the signal constantly by a factor or 10. D1 and D2 clip the signal which is then fed to A4. The noise signal comes from the junction of R9 and R10. Opamp A7 is another impedance
converter. A8 is used to drive a VU meter.