[sdiy] 2164 Korgasmatron VCF

[David G. Dixon]

> In the Jung opamp book there is a method of placing a bridge rectifier
> across
> the integrator cap and placing a voltage reference across the 'dc'
> terminals of
> the bridge. This would allow for adjustable clipping as well as
> asymmetrical
> clipping.

One thing about using zeners is that they give a very gnarly looking wave
when the resonance amp is overdriven by a large margin.  I've got mine set
up such that self-oscillation occurs (in principle) at a Resonance pot
setting of 60%.  This gives quite a bit of headroom for distorting the
resonance.  At high pot settings, the resonance sines start to look almost
like ramps.  With the adjustable zener voltage (what I call "Amplitude" on
my panels), and some judicious tweaking of the input signal level, one can
get strings of these mini-ramps on the original signal, at any frequency and
amplitude relative to the original signal, and either at a constant
amplitude or a decreasing amplitude.  I'm hoping (when I finally plug this
thing in) that this gives some interesting sounds.