ARP 1004 (1970–1977)

Name: ARP 1004
Brand: ARP

The ARP 1004 is the voltage-controlled oscillator module at the center of ARP's early modular systems. Alan Pearlman engineered it with a temperature-compensated core. That gave the 1004 unusually stable pitch, at a time when most modular oscillators drifted noticeably after warming up. "Plug in an ARP 1004 VCO, power it up, and within 20 minutes you're not just in tune - you're staying there," as one collector's account puts it.

The module generates both triangle and sawtooth waveforms, and has a manual sync switch on the panel. The sawtooth core is reset by the square wave derived from the triangle oscillator. That technique gives the 1004 its characteristic aggressive sync sweep. A Studio Sound (May 1975, p.52) survey listed the UK price at £399 and gave dimensions of 820 × 300 × 100 mm, weight 8 kg. Those figures likely describe a complete system housing the 1004 rather than the module alone, since the details suggest a full cabinet.

Little is documented about the 1004 in isolation. It appears to have been produced from 1970 through 1977. No frequency range, output level, or power supply specifications have surfaced in the available literature. What collectors know comes mostly from surviving units and the lore of ARP's early days.