Vintage-sounding 921 VCO module from the '70s. Authentic reproduction of the circuitry from the "Modular 55, 35 & 15" Series. The artist roster includes the world's most famous pop, rock and jazz musicians. The VCO features 6 selectable waveforms: sine, triangle, saw, inverted saw, square, and inverted square. Pulse width control with 2 separate CV inputs for fat PWM sounds.