ARP 2500

The ARP 2500 is a monophonic (or duophonic) analog modular synthesizer. It was the first product of ARP Instruments, built from 1970 to 1981. Although only about 100 units were made, Sound on Sound magazine later called it "undoubtedly one of the most important electronic musical instruments ever made." It is notable for being programmed via matrix switches instead of conventional patch cables. Demand for smaller and more affordable instruments led ARP to develop the semi-modular ARP 2600 and the fixed-architecture ARP Odyssey.