Four oscillators (SSM2033 chips) with TUNE, WAVEFORM (triangle,saw, pulse width modulation, pulse wave), OCTAVE (2',4',8',16'), and LEVEL controls. Oscillator one has MASTER TUNE knob, the other three oscillators are tuned in relationship to it. Also independent white NOISE source with LEVEL control. In earlier Mono/polys the noise source is a digital MM5837 chip, but later versions use discrete analog circuitry.