PO Modular Tuning Problem

Hi, I‘m having trouble with the tuning of my PO170. I‘m sending cv from the op-z via the oplab module. And I can‘t get it tuned right. The middle octave is in tune, the higher and lower octaves are out of tune.

Does anyone knows what I‘m doing wrong?


@flom: hopefully I’m some help this time! Have you calibrated the oscillator? There’s a little screw for tuning on the back of the oscillator (you can also calibrate the filter’s cutoff and resonance on the back of that module too).

Hi @5StarNomad , thanks for your reply. I will have a look at the module and the screws tomorrow.

Did anyone used those screws for tuning before?

What does the screws do at the filter module?


Honestly - mine from stock didn’t keytrack very well past ~3-4 octaves. I wouldn’t expect much more than that given the nature of the circuitry - but I don’t know the official stance on the tuning range.

*Edit - I’ve got the PO-400, not the 170 - but almost definitely same oscillator circuits used.

I tuned mine via the screws on the modules. You have to unscrew them from the chassis. It works fine now. All octaves are in tune. VCO tuning and scaling issues

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