Analog sequencer

An analog sequencer is a music sequencer constructed from analog (analogue) electronics, invented in the first half of the 20th century.

Raymond Scott designed and constructed some of the first electro-mechanical music sequencers in the 1940s. Incidentally in 1951, computer music was started from the music sequencing, and later its applicable fields were expanded into the music composition and sound generation. However, the RCA Mark II Sound Synthesizer in 1957 was still indirectly controlled via punch-tape system similar to piano rolls, a kind of mechanical sequencer. Also, in earlier electronic music, artists used sound-on-film technology to generate sound waves as well as control sequences of notes.

At its most basic, an analog sequencer consists of a bank of potentiometers and a "clock" (pulse generator) connected to a sequencer, which steps through these potentiometers one at a time and then cycles back to the beginning. The output of the sequencer is fed (as a control voltage and gate pulse) to a synthesizer. By "tuning" the potentiometers, a short repetitive rhythmic motif or riff can be set up.

The most commonly used analog sequencer was the Moog 960, which was a module of the Moog modular synthesizer. It consisted of three parallel banks of eight potentiometers: the three banks could either steer three different Voltage-controlled oscillators (VCOs) to allow three-note chords in the sequence, or (for example) one row could steer pitch while the second row is patched through to the filter cutoff or VCA volume, and a third steers filter cutoff for a white noise generator (thus creating an extremely primitive electronic drum track).

...
Wikipedia