image courtesy of Atmosfear

The Moog Source is a 2-VCO, micro-processor-controlled, programmable monophonic synthesizer, with 16 memory locations, and a 3-octave, 37-note (C-C) keyboard. It features an arpeggiator and a digital sequencer with memory for two seqences of up to 64 notes. The Source was one of the first to use digital parameter access for programming, a method now commonly found in today's synthesizers, using membrane switches, a two-digit LED display and a single data knob. Both VCOs have three available waveforms (sawtooth, triangle, and pulse; with pulse width modulation) and three available octaves (32', 16', and 8'). VCO2 can be detuned at fixed intervals and it can be also synced to VCO1. The mixer section features levels for VCO1, VCO2 and Noise. The VCF (24dB/octave) has parameters for keyboard tracking (off, 1/2, and full), cutoff frequency, resonance, and contour (Moog's word for envelope) amount. There are two ADSR envelope generators, one for the VCF and one for the VCA. The envelopes can be set in single or multi trigger modes. The LFO (triangle and square waveforms) can be routed to the VCOs and the VCF. The Source also features a sample-and-hold which can be routed to the VCF. To the left of the keyboard is the pitch bend and the modulation wheel, along with two octave-switching buttons. These and a volume knob are the only dedicated controls. On the back panel are the audio out, cassette interface, a recessed pitch knob (for fine tuning), and CV and S-trigger inputs and outputs.

[from The A-Z of Analogue Synthesizers , by Peter Forrest, published by Susurreal Publishing, Devon, England, copyright 1994 Peter Forrest]