The Oberheim OB-X was the first of Oberheim's OB-series polyphonic analog subtractive synthesizers.
Oberheim OB-X
Oberheim OB-X internal view
Oberheim is an American synthesizer manufacturer founded in 1969 by Tom Oberheim.
SEM (1974)
4-Voice (1975)
OB-1 (1978/1979)
OB-X (1979)