New Steiner Parker VCF problem

[dancelwerk]

Hello to everybody,

Recently I remake my Steiner Parker VCF, but I have a problem now with this wonderfull filter,

first: I have problems with the cutoff, when I move this pot sounds noise all time. I changed the pot two times and I have the same result.

second: I have a noise (hummmmm) when I use the filter with CV normally, when this "hum" appears, it stay it all time, even with no input, I disconnect the input and witih the resonance at 0, but it sounds.

I think the resonance works good and the 4 pole filter selector too.

I think that is a problem with the cutoff.

Can somebody help me?

Thanks in advance.

Dancelwerk.

[dancelwerk]

I forget it, my filter use a 2sc1583 transistor