AW: J.H.'s WASP-filter-clone

[Martin Czech]

> The self oscillation of the Wasp Filter is a really pleasant one.
> Not the usual MHz stuff you find with shielded cables on opamp
> outputs, but rather an undamping of the state variable filter so that
> it oscillates at maximum Q setting.
> 
My version doesn't oscillate at all ! Well, the caps have 10% tolerance,
and I took the original feedback network from your drawing.  Maybe I
have to change the network, you have two diodes in there, I guess for
amplitude limiting, so by that I could have seen, that this filter was
made for oscillation.

Very likely: "amplifier" gain insn't enough, these are just inverters.

m.c.