The GMSN! Pure VCO is a classic analogue sound source. It has saw, triangle and pulse outs, with coarse and fine control of the frequency across the whole audio range right down to LFO frequencies. The pulse width can be set from 0 - 100% with 50% being square wave out. There is also 1 volt per octave CV In, FM In with control of the level, PWM in, again with control of the level and an Audio Sync In.