The ARP Avatar was a 1977 guitar-controlled synthesizer module. It copied the ARP Odyssey’s synthesis architecture but removed the keyboard and added a 6-way fuzzbox. It required a hexaphonic pickup and pitch-to-voltage conversion. It failed commercially. Sales totalled $1 million over two years against $4 million spent on R&D and production. It contributed to ARP Instruments’ bankruptcy in 1981.
The ARP 2500 is a monophonic or duophonic analog modular synthesizer introduced in 1970 as the first product of ARP Instruments. It used matrix switches instead of patch cables, enabling a cable-free experience but suffering from dirty connections and crosstalk. Its voltage-controlled oscillators achieved good tuning stability compared to competitors, due to patented exponential converters and a dual core design. The matrix switch scheme allowed any module's output to connect to any other module's input.
ARP Instruments (1970) built analog synthesizers focused on stability, usability, and performance readiness—not abstraction or infinite patchability.
The ARP Omni is a polyphonic analog synthesizer with preset orchestral string voices, a monophonic bass section, and a polyphonic synthesizer section featuring a 24 dB/oct VCF, ADSR envelope, triangle LFO, and waveform enhancement switch. Its string and synth sections used divide-down architecture for full polyphony, and it offered simultaneous, mixable, separately outputted sections — Strings, Synthesizer, and Bass — with onboard chorus phasing applied primarily to the strings.
The ARP Quadra is a 61-key analog synthesizer introduced in 1978. It was built as a paraphonic instrument using pre-existing ARP modules. It features four sound sections (Bass, String, Poly Synth, Lead), limited memory that recalls only on/off states and intervals—not slider positions—and relies on manual real-time adjustment. Its architecture uses divide-down circuits for the string section and shares controls like the hollow wave button across sections. It is not truly polyphonic and includes an arpeggiator specific to the lead section.
The ARP 2600 is a foundational analog synthesizer designed for education. Its semimodular architecture, front-panel signal graphics, and duophonic voice count reflect its classroom purpose—not stage use. Its original filter was replaced after a patent dispute. It teaches synthesis more directly than any contemporaneous instrument, but offers no polyphony, no presets, and unstable tuning.
The ARP Odyssey is a duophonic analog synthesizer introduced in 1972. It was designed as a portable, performance-oriented alternative to the Moog Minimoog.