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.
Schematic Layout PCB
transfer
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 untill you start rocking the CV pedal
forward.
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 this next photo, you can sort of 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.



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