Note: below the text and images you’ll find the original ARP 2500 brochure.
The 2500 was designed in 1969 by former NASA engineer Alan R Pearlman (hence ARP) who was responsible for amplifier design on the Gemini and Apollo space programmes. When the instrument was commercially launched in 1970, it was an enormously complex undertaking, combining all the features of the Moog modular series that was available at the time, plus a lot more. Where it differed was to allow the musician every possible combination of choice in sound creation within a matrix system, rather than using the more familiar patch cords (see the ‘Matrix Switching’ box for an explanation of this system).
Several variations of the 2500 were made, by far the most common of which was the single large cabinet configuration (model 2515) with a single keyboard. Additional, smaller ‘wing’ cabinets (model 2508) with a second keyboard were optional, with the 2500 able to continually add these on as required. An even rarer example of a triple cabinet (model 2524) exists, but very few were ever made. This would bring the full complement of modules in three cabinets to 31 ‘function modules’ — 15 in the centre cabinet, with eight in each of the wings (this includes power control modules) — plus two 61-note, 5-octave keyboards.