Analog synth

An analog (or analogue) synthesizer is a synthesizer that uses analog circuits and analog signals to generate sound electronically.

The earliest analog synthesizers in the 1920s and 1930s, such as the Trautonium, were built with a variety of vacuum-tube (thermionic valve) and electro-mechanical technologies. After the 1960s, analog synthesizers were built using operational amplifier (op-amp) integrated circuits, and used potentiometers (pots, or variable resistors) to adjust the sound parameters. Analog synthesizers also use low-pass filters and high-pass filters to modify the sound. While 1960s-era analog synthesizers such as the Moog used a number of independent electronic modules connected by patch cables, later analog synthesizers such as the Minimoog integrated them into single units, eliminating patch cords in favour of integrated signal routing systems.

The earliest synthesizers used a variety of thermionic-valve (vacuum tube) and electro-mechanical technologies. While some electric instruments were produced in bulk, such as Georges Jenny's Ondioline, the Hammond organ, and the Trautonium, many of these would not be considered synthesizers by the standards of later instruments. However, some individual studios and instruments achieved a high level of sophistication, such as the Trautonium of Oskar Sala, the Electronium of Raymond Scott, and the ANS synthesizer of Evgeny Murzin. Another notable early instrument is the Hammond Novachord, first produced in 1938, which had many of the same features as later analog synthesizers.

...
Wikipedia