[sdiy] SSM2164 state variable filter

[David G. Dixon]

> >> Try putting the limiting in the LP path.
> >
> > Please don't...
> 
> Could you expand on the "don't" part?  Works for me, giving near-
> constant amplitude in self-oscillation from 4Hz to about 16kHz:
> 
> http://www.milton.arachsys.com/nj71/pdf/cesyg/vcf-sch.pdf

It simply doesn't work on the 2P version, at least according to my
simulations, to apply the zeners to the lowpass output as you have done.
All I get are trapezoids out of the LP and HP outputs, and a clipped
triangle out of the BP output.

However, your filter is a completely different topology, and the landscape
around your resonance amp is infinitely more complicated than mine, so I
can't really comment beyond that without doing a complete simulation of your
filter, which I'm too lazy to do.