Oscillating Cherry Bomb

[Sigesmundninja]

That turret-board-Cherry-Bomb I showed in the "build-report"-section keeps bugging me. It Sounds great to me but there is one issue. If i keep the treble-knob at "0" There is no issue. But if the Gain is turned up to 80% and above and the treble is anything but "0" it oscillates and the pitch changes with the treble-knob. What would cause something like this this?

Transistors are the ones recommended in the docs: 2n3904 for Q1 and Q3 and a 2n2222 for Q2.
Used a 2Kb pot for gain.

[madbean]

If you have a DMM that measures Hfe, yu might check the gains on the three transistors. Could be that they are too high. If you have some other medium gain transistors like the 2n3904 and 2n2222 try picking some with a lower Hfe to see if that solves the problem.

You could also try a 100R resistor between the 9v supply and the 9v connection to the circuit.