JP6 filter resonance CV

I'm testing the component based JP6 filter on a breadboard. I have some initial problems getting it to work, but then I realised that resonance is probably turned up way too high.

This made me take a look at how I generate the CV and how it affects the circuit.

This is the current circuit. The reason it is so large is that the resonance works backwards, feedback is needed to stop resonance rather than introduce it, so the CV is inverted from 0-5V to 0- -5V, then moved up 5V to get the correct response: 

Measuring CV vs I_abc/V_abc/V_collector. NB: For +/-15v supply

CV (V)	I_abc (uA)	V_abc (V)	V_tran (V)
0	-126.0	-13.38	-12.11
1	-101.7	-13.39	-12.37
2	-77.0	-13.40	-12.6
3	-52.0	-13.42	-12.9
4	-27.5	-13.46	-13.18
5	-2.7	-13.58	-13.55

I have noted in my simulation that the CV must increase rapidly and then slow down, which means that I will have to manipulate the output from the synth matrix. In that case I may just as well just invert it while we're at it, so 5V is no reso and 0V is max. That really simplifies the circuit. Also, just using a 20k resistor at the input seems to work fine though it needs testing. In that case I reduce the number of trimmers needed by two, which is really good.

Measurements again - the results are similar to the previous ones, just reversed

CV (V)	I_abc (uA)	V_abc (V)	V_tran (V)
0	0	-14.3	-14.28
1	-24.8	-13.46	-13.2
2	-49.5	-13.42	-12.9
3	-74.3	-13.40	-12.7
4	-99.0	-13.40	-12.4
5	-123.8	-13.38	-12.14

It is interesting to note that the max current is so low (125-ish uA). It probably means that no change to the R_abc (which is 2 x 10k now) when switching to 12V supplies, though that has to be tested.