One of the first polyphonic synthesizers, originally offered by Moog Music in 1975. The Polymoog was exceptional in that it was fully polyphonic -- every note on the 71-note keyboard could be played simultaneously and all would sound notes. For a brief period in the mid-'70s it was wildly popular with top synth players, who could afford the $5000 US price tag (as much as a mid-size car in 1975!) It was very compact for its day; it had an extensive set of output options, and sported an early, primitive version of multitimbrality with a keyboard splittable into three zones. The Polymoog was a further development of the Apollo prototype synth that had been part of the Constellation concept (which also spawned the Taurus bass pedal synth).
However, the Polymoog had a number of frustrating limitations. The original model came with eight hardwired presets and one "variable" mode in which the front panel controls determined the sound. A big problem was with filtering; only in the preset mode did each voice have its own filter. When the variable mode was engaged, the synth became paraphonic in that there was only a single VCF for the whole synth. When playing a chord, the VCF would track the highest note played, leaving lower notes almost unfiltered. Also, although the synth had two VCOs per voice, the VCOs were actually based on a divide-down architecture. As it always does, this produced thin, "weedy" sounds when playing chords, and it was difficult to get either a lush or an aggressive sound. The cramped panel controls also came in for some criticism, particularly since the synth had no patch memory.
But the worst problem was the Polymoog's unreliability. The power supply was marginal; the custom ICs that did the voicing failed frequently, and the non-microprocessor control systems were spastic. A huge number of engineering change orders were applied both at the factory and in the field to try to improve reliability, to little good effect. The Polymoog quickly got a bad reputation and most performers who had initially welcomed it soon turned elsewhere.
In a sense, the Polymoog was the beginning of the decline of the original Moog Music. The synth was designed largely by Moog engineer Dave Luce; Bob Moog thought it was a bad idea and removed himself from the project (and shortly after, the company). During the design process, the company was purchased by Norlin, which instituted cost-cutting that resulted in the Polymoog being cheaply built, with a casing that flexed the circuit boards and an insufficient power supply. Some performers found the synth's architecture hard to understand, and by some reports Luce was singularly unsympathetic to requests from the company's endorsers for changes.
Two models of the Polymoog were produced, the 203a and the 280a. The 203a was the original model with the full set of editing controls; the 280a was a lower-cost model introduced in 1978 with more presets but very limited editing capability (it can be quickly recognized by its lack of controls on the right half of the panel). Confusingly, the 203a was marketed at different times as both the "Polymoog Synthesizer" and the "Polymoog Keyboard", while the 280a was also marketed as the "Polymoog Keyboard". Neither model sold well after the initial burst of interest for the 203a; Yamaha stole Moog's polyphonic thunder with the CS80 in 1977, and then Sequential Circuits' Prophet-5 arrived in 1978. Both of these synths had the patch memory which the Polymoog lacked, and vastly superior voice architectures, and most performers considered this a more-than-fair tradeoff for full polyphony. Both models of the Polymoog went out of production in 1980, and few remain in working condition today.