Lightly used Plague of Demons, a wild and powerful analog VCO. Power cable included.

From NLC:
This VCO uses analogue switches to achieve the thru 0 function, based on ideas presented in Electronotes EN#75 which were in turn based on suggestions by Bob Moog.

The FREQ pot is a fine tune pot to set the module up for phase reversal, the LEDs indicate when this happens.

If nothing is patched into the CV INPUT, the CV pot functions as a tuning pot to set the module up for higher frequency operation. Once a CV signal is patched in, the pot becomes an attenuator and the signal is summed with the signal from the 1V/OCT jack.

SELF CONTROL allows the sine output signal to be fed back into the Frequency modulation sub-circuit, the DEPTH control will need to be turned up for this to have an effect, or (better) use a CV on the FM ENV input.

SAW and PULSE are both controlled by the PW pot and PWM input. PULSE will have its width varied, SAW will become chopped and morph into a complex, harmonically rich waveform eventually its frequency will double.