Shruthi Polivoks filter does not self-oscillate. Is it normal?

Hi. I can’t get polivoks filter board self-oscillating with following settings: osc1 and osc2 set to none, cutoff 64, reso 63, env and lfo 0.
I know, it doesn’t require v/oct tuning. Apart from this it is working ok and sounds perfect. Is lack of self-oscillation in polivoks filter normal behaviour?

Do you have the digital control board set to polivoks (pvk)?

Hi. Yes, digital control board is set to pvk. I just wondering if there’s no need of tuning then circuit is not self-oscillating at these settings. Maybe I am wrong. I’ve checked all resistors and other components.

There is nothing to tune ont the polivoks. It’s also very quirky so probably impossible to tune if you wanted to. But it should be able to self oscillate. Does the resonance work at all?
Did you check at other cutoff settings if it wil resonate?

Resonance work fine . Even if cutoff and resonanse is set on max it wont self-oscillate. Have you got shruthi with polivoks so you can check how your behaves?

I have a sidekick with a polivoks filter. I don’t have it here at the moment but i’m quite sure it can self oscillate.
Some filters need some input to start. How is it with the oscillators on? or just noise?

If it doesn’t work than and all your parts are in the right place than it might be a bad solderjoint.

Do you have a picture of your board ? both sides?

It works ok, even when only one of two oscillators is on. I can hear cutoff filter and resonance working. Don’t have a picture couse it is already in coloured case. But I am sure of soldering, could be tolerance of some resistors summed up.

I mean if it self oscillates with the osc’s on?

did you use 1% resistors ?

what is the voltage of your adapter? try to use something that does exactly 9V. If it’s higher the regulators get very hot and can influence the rest of the circuit.

All resistors are 1% but I had some experience in the past with op-amp when 1 or 2 hundreds ohms plus at 33k resistor and then having another resistor going minus 100-200 ohms made a difference at gain factor.
I tried 9v and 12v dc power supply also.
Can I ask you to check your polivoks ones you have a time . I would appreciate that. It could save me a lot of time. Thanks in advance.

Hi heniek…
my polivoks sikekick seems to be buried somewhere.
here is a video on youtube i found of someone demoing the polivoks
at around 5 min it’s on full reso.

Hi shiftr for replay.
Comparing my Shruthi to this one in youtube video it sounds almost identical. So I think, no self-oscillation at both oscillators set to off is normal.
It might be nature of polivoks filter.
Thanks for all.

I have just tested it with my Shruthi with polivoks filter: it does self-oscillate!

Hi cj55. Are you using these settings: osc1 and osc2 set to none, cutoff 64, reso 63, env and lfo 0 ?

Yes. Best to use the init patch to make shure there are no special settings in the modulation matrix. It even works in a great range of the cutoff setting, but resonance have to be min. 62 on my Polivoks Shruthi.

Many thanx. That means I have to investigate this. I just wondering is this really important thing, board is working great and resonance is enough at 63. Is it any point to gain resonance if most patches don’t go with resonance over 60. Considering fact that, boards doesnt need tuning.
Thanks anyway.

If you are happy with the way it sounds now… why change it? What you miss is manic screaming.
Which can be something you want.
I suspect there is a bad solder joint in the resonance circuity going to ground. Or maybe maybe maybe the transistor supplying the current that controls the resonance is a bit off.