Distortion Synthesis
In contrast to subtractive synthesis, where timbre is controlled by shaping the spectra of waveforms with a many spectral components, distortion methods shape the sound by adding overtones with different principles. Quasi parallel to Bob Moog, Don Buchla invented his own system of analog sound synthesis in the 1960s, based on distortion, modulation and additive principles. This approach is also entitled West Coast Synthesis.
The Buchla 100 was released in 1965, and was used by Morton Subotnick for his 1967 experimental work Silver Apples of the Moon.