Unlike most other attempts at fully polyphonic synths of the 1970s, the PS-3100 was not paraphonic; each note had a voice consisting of its own signal source, voltage controlled filter, voltage controlled amplifier, and envelope generator. The main compromise was in the signal sources. The synth had a bank of 12 voltage controlled oscillators, each set up to play a specific note of the equal tempered chromatic scale -- the first VCO played C, the second one C#, the third one D, and so on. These 12 VCOs were connected to the 12 keys of the top octave on the keyboard; top-octave division was used to produce the notes of the lower octaves. (This led to the keyboard having an unusual span of F to E; it was necessary for the number of notes to be a multiple of 12; hence, the typical "extra" top