[sdiy] 24dB multimode VCF it seems to work!

[Theo]

Hi all,
I've been toying around with about 8 different multimode designs last week.
At some point I wondered why all multimode filters are 12dB.
So I tried to make  24dB version and guess what, the thing seems to work!
I've to do some more testing and measurements before I dare to say it really
is practical.
So far the noise level is a problem, but that might be the crappy psu I
used.
Its AM radio all over the place :(

The 24dB VCF has "two" resonance pots.
One as expected in the feedback loop from BP output to input.
And the other the in the negative feedback loop form LP output to input that
creates the HP mode.
Turning this second resonance pot up gives strong resonant effects.
Needless to say it kills the low end but compared to 12dB vcfs the filter
sounds much more resonant without having it self oscillating.

I'll come back on this when there is progress on my side :)

Cheers,
Theo

PS. It would surprise me in nobody else on the list has tried a 24dB
multimode VCF before.
If so how did it go?