Moog Polymoog 203a (1975–1978)
The Polymoog 203a was Moog's bid at full polyphony, released in 1975 and built on divide-down oscillator technology. That architecture is closer to the electronic organs and string machines of the era than to anything else in the Moog catalog. It grew out of the Constellation, a large ensemble system Moog had been developing, and the 203a was the commercial distillation of that project. There is no patch-cable flexibility. You get eight preset sounds: Strings, Piano, Organ, Harpsichord, Funk, Clavi, Vibes, and Brass. They run through the classic Moog ladder filter at 24 dB/octave with an ADS envelope and a fixed-waveform LFO. The keyboard was touch-sensitive.
It is remembered as one of the first polyphonic synthesizers, and Prince used one on his debut album For You, credited in the liner notes as "Ms Poly Moog." But these are big, heavy, complicated instruments, and restoration is lengthy and therefore expensive. The voice-card design is the usual trouble spot. A "fully working" 203a with six bad voice cards shifted to the top of the keyboard range has actually sold, so verify every voice before committing. Serviced units command a premium; one example was maintained by Synthchaser in August 2023. Current asking prices on the used market typically run from around $3,500 upward, with one synth.market listing showing a $4,000 street price. No original launch price survives in the record.
The 203a was followed in 1978 by the Polymoog Keyboard 280a, a streamlined iteration that dropped the dedicated monophonic lead section and added presets including Vox Humana, Electric Piano, and Honky Tonk Piano. The 203a's lid fits the 280a. The only case difference appears to be the rear interface panel.
Documentation is thin, and a few figures conflict across sources. Keyboard size is given as 71 keys in one place and 80 in another, and polyphony as either 71 voices or eight notes. The eight-note figure is attributed elsewhere to the 280a, so treat both numbers with caution. Production years are given variously as 1975-1978 and 1975-1980. No dimensions, weight, or original retail price have surfaced. The service manual (Volume II, schematics) survives and is the best technical reference for anyone restoring one.
- Released 1975; production commonly given as 1975–1978 (some sources say 1980)
- Hybrid polyphonic analog synthesizer, divide-down oscillator architecture
- Eight presets: Strings, Piano, Organ, Harpsichord, Funk, Clavi, Vibes, Brass
- Moog 24 dB/octave ladder filter, ADS envelope, fixed-waveform LFO
- Touch-sensitive keyboard (71 vs 80 keys disputed in sources)
- Descendant of the Constellation project; succeeded by the Polymoog Keyboard 280a (1978)
- Used by Prince on For You (credited as "Ms Poly Moog")
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