An input into part of the synthesizer that allows that bit to be modulated by another part of the synth. For example there is a control input in the amplifier which controls the level of amplification. If a very slow sine wave (an LFO) is patched into this input then the sound will slowly get louder and quieter. If an LFO was patched into the control input of the oscillator instead, then the sound would go higher and lower in pitch....
Electrocomp 500
The Electrocomp 500 is a 2-VCO, monophonic, analog synthesizer with a 3 1/2-octave,
44-note (F-C) keyboard. It was designed to compete with the Minimoog and the ARP
Odyssey. The 500 is more of a keyboard instrument, as opposed to its predesessor, the
semi-modular 101, using switches and sliders as opposed to knobs and patch cords. Its
voice structure is basically a simplified 101 design, with VCO1 outputting only a
sawtooth or square wave. The 500 features a resonant multimode VCF (switchable
between low-pass, band-pass, and high-pass) a single ADS envelope generator,
sample-and-hold, ring modulation, a mic preamp, noise, and an LFO (with six available
waveforms). The back panel featured both hi and low outputs, as well as a headphone
jack, a pitch selector (switching between one octave above or one octave below
normal), sustain pedal input, and interface connections (S1 and S2 sockets).