antto wrote:make sure you're using the right adaptor - 9V AC around 300 to 600mA ... you might also want to measure it's output (with multimeter in AC Voltage mode) to see if it's not terribly off or something
i'd also look around the IO-board closely, for anything suspicios
if this issue only affects the VCO but not the VCF tuning - it could be somewhere in the VCO section instead
did you try sweeping the TUNE knob to see if it shifts the vco pitch smoothly?
The label on adapter says that it is 9V AC 500 mA. When measured without any load the voltage seems to be 11V AC, but with x0xb0x running, the voltage is 10.55V AC.
I think the problem affects both VCO and VCF.
IMHO, the TUNE knob shifts the pitch smoothly.
Btw, I have now an oscilloscope available. Any ideas what I should try to measure with it?