J.H.'s WASP-filter-clone

[Martin Czech]

Also this weekend (yes' I locked me in, closed the window und switched
off the telephone, and switched on the iron instead ;->>): J.H.'s
WASP-filter-clone. A nice cicuit. Runs imediately (after removing some
wiring mistakes by me, the circuit diagram is correct). The noise is not
too bad (and I'm very sensitive to all kind of audio dirt, I can tell
you), only at very high resonance (well, different hex inverter chips could
have different noise figures, they aren't made for this). 

Of course I had to change a bit: I tryed the distortion add on BEFORE
the filter, very nice.  And then I tryed different supply voltages
(original 9V I guess). Also nice distortions. Next I'll use differnt
supplys for the inverters (variable supply voltage) and for the otas,
so I can control distortion and not change the frequency too much. And
after filter distortion.  I think, all put in a switch to change from
pre to post filter distortion.  And an expo converter would also be nice.

Two questions: 

Juergen, did you change anything from the original schematic other than
the distortion filter addition ?

Did someone modify the feedback path for more resonance/oscillation ?

m.c.