[sdiy] SSM2164 state variable filter

[David G. Dixon]

> This works very nicely. The sine wave oscillation amplitude varies from
> about 1.5V at the lowest frequency to about 6.6V at the very highest. This
> is a considerable improvement over other places I've tried putting various
> types of clipping network.

Simulation suggests that the sine wave amplitude should be fairly constant
down to the bottom of the audio range.  1.5V seems too low.  What was your
minimum frequency?