A stable, reliable analogue VCO with a rich warm sound.
The design is based around the AS3340 triangle-core oscillator IC which itself was based on the legendary Curtis CEM3340. We have ironed out the quirks of the AS chip so it now sounds and behaves just as good as the CEM3340. The addition of an 11-pole +/-5 octave switch makes it useful and reliable as a live VCO. The center position being approx C1 means it can be pitched down well into down into VC-LFO territory.
The TUNE control allows for trimming of the pitch by half an octave up and down while PULSE WIDTH sweeps the duty cycle of the square wave from 50% to just under 100% positive. The additional attenuated PWM input allows for voltage control of the duty cycle which can surpass the range range reachable by the knob.
Besides the OCTAVE and TUNE controls, the pitch can be modulated via the V/OCT input (at 1v/oct) and also by the separate, attenuated FM input which can either effect the frequency in a linear or exponential fashion.
Adding a pulse or ramp wave from another oscillator will (negative) hard sync the VCO-3340.