ARP 2500
ARP's first synthesizer, introduced in 1970 and notable for its pitch stability.
Introduced in 1970 as ARP’s first synthesizer, the modular ARP 2500 arrived after Moog’s and Buchla’s earliest instruments but drew attention for a comparatively rare feature at the time: it held its tuning without drifting. Only around 100 units were built, with an estimated 50 surviving in working order; many were bought not by music departments but by university science departments as a demonstration instrument for analog electronics, including one still used for teaching at the University of Virginia’s Center for Computer Music. Éliane Radigue worked with her own 2500 from 1974 to 2000, and a fully loaded unit with two wing cabinets and dual keyboards appeared on the set of Close Encounters of the Third Kind (1977); a surviving unit is on display at the National Music Centre in Calgary.