Hello

> Put a keyboard on it Dieter, and you would rule the world.

+1
Absolutely. And if you clone the SH101 sequencer for it too, you would
rule the universe.

> (e.g. probably a 12 dB multimode filter with
> lowpass, highpass, bandpass and notch instead of the 24 dB lowpass)

btw: Until now all filters where some kind of "clones" (ok, the CEM3320
filters where mostly the circuit suggested in the datasheet examples).

I think it might be cool to have two dedicated Doepfer Filters.
A 12dB state variable filter (which already exist with the DIY synth),
and a 24dB OTA-based four stage filter, built with available components
like LM137000. The basic 4-stage circuit could be used in a high pass or
low pass filter (similar to the CEM3320 and or the roland IR3109).

Florian