The Screaming Meanie sounds horrible. And, that’s kind of the point. There’s a built-in oscillator that just makes a lot of really annoying noise. The frequency (pitch) of the oscillator can either be set with the frequency control or, for even more fun, it can be controlled with a CV pedal, as in the second clip in each pair of clips, above.
Electric Guitar
Electric Bass
If you don’t like hearing the oscillator squeal as soon as it is turned on, the 5K trim pot (TR1) can be adjusted to silence the oscillator at the minimum frequency (VR1). That way, if you plug in a CV pedal and leave it positioned all the way back, when you switch the oscillator on, it won’t be audible until you start rocking the CV pedal forward.
Project files corrected/updated Aug 2012:
Schematic
Layout
PCB transfer (resize to 2.9″x0.9″)
Wiring diagram
SW2 turns the oscillator on/off. In the schematic, it’s shown as a SPST switch. But, I used a DPDT switch and included an LED to indicate when it’s switched on.
Inside the enclosure, the circuit board sits on top of the pots. In the photo on the left, you might be able to see how I used some double-sided carpet tape on the backs of the pots, with only one side peeled off, to insulate the traces from shorting out.
