Yamaha CS-70M (1981)
Yamaha's flagship polyphonic answered the Prophet-10 with a built-in polyphonic sequencer - and the players who actually owned one were not entirely convinced.
Overview
The CS-70M landed in 1981. By then the polyphonic synth market had sorted itself into camps, and Yamaha's big CS was aimed at the top of it. It carried a polyphonic sequencer onboard, and that was notable enough that contemporary players used it as shorthand for the whole class of machine. Nick Rhodes of Duran Duran listed his keyboards for Electronics & Music Maker in 1981. He grouped the CS-70M with the Prophet-10 as the two instruments offering built-in polyphonic sequencing, then added that he wasn't much impressed with either implementation and wanted to see the concept developed properly. So it was respected for what it attempted and criticized for how far it got.
The instrument shows up repeatedly in the British electro-music press of the period. It was covered in the December 1981 issue of Electronics & Music Maker alongside the Roland CR5000 and CR8000 drum machines and the Fostex 250. The magazine also put its sound on Demo Cassette No. 5, the companion tape bundled with the December/January issues. A written review and a spot on the demo cassette in the same cycle says the UK press took it seriously. It also turns up in the published improvisation notes of at least one composer working with Yamaha's GS1, where the CS70M is named among the instruments used to realize orchestral-flavored pieces.
The surviving documentation does not give the hard specification sheet collectors would want. There is no oscillator count, no filter topology, no voice architecture and no original retail price. The CS-70M is well attested in the contemporary press, but the detailed engineering record has not surfaced in the sources available here, and this archive will not fill those holes from memory. Anyone chasing service data or a definitive voice count should treat the period magazine coverage as a starting point only.
What can be said with confidence is that the CS-70M held the flagship position in Yamaha's CS line at the turn of the decade. Its reputation among working players was mixed in a specific way: the sequencer was the talking point, and it was also the complaint. Collectors who find one should expect a substantial, complex instrument from Yamaha's most ambitious analog era, and should expect to do their own homework on the internals.
Similar items on eBay
No exact Yamaha CS-70M listings are live right now — these searches show current Yamaha and similar vintage audio gear on eBay:
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.
Related Models
- Moog Lamarr (1984)
- Moog Minimoog Model D (reissue) (2016-2022)
- Moog Polymoog 203a (1975-1978)
- Roland RS-09 (1978)
- Roland RS-505 (1977-1978)