Prehistory
YAMAHA GS1 is their first digital FM synthesizer. It can only be edited by the dedicated computer at YAMAHA, and the details of its synthesis engine is not known. The manual says it's an 8-Operator FM synthesizer (4 Carrier/4 Modulator/8 EG). Though it has no MIDI, it's one of the earliest synth with velocity sensitivity and polyphonic aftertouch. GS1 is 16-polyphonic, and has 3-band EQ and analog chorus.
Later GS2 came out with 4-Operator architecture (2 Carrier/2 Modulator). Polyphonic aftertouch is omitted in this model.
CE20 / CE25 are 8-polyphonic compacted packages. They are basically preset synths, but still had velocity and aftertouch (maybe non-polyphonic).
YAMAHA GS1 (1981)
YAMAHA CE20 (1982)
All share 6-OP, 12-bit D/A architecture. See DX7II and DX7I / DX7II sound comparison pages for later 16-bit evolution of DX series.
DX7: one of the first synth with MIDI, velocity and aftertouch.
YAMAHA DX1 (1983)
YAMAHA used FM synthesis in their Electones, too. HX electones and FVX-1 module were 8-Operator FM synthesizer that seems to use 12-bit D/A, and it could have been the evolution of DX7 I series.
YAMAHA DX9 came out at the same time with DX7. DX9 is a 4-Operator version of DX7, without velocity and aftertouch.
YAMAHA FVX1 (1987)
FVX-1 8-operator algorithm
Later YAMAHA redesigned the 4-Operator architecture, and 4-OP synths have evolved in its own way, even still now in the form of mobile phone chips. For the history of 4-OP evolution, see YAMAHA DX21, YAMAHA FB-01 and KORG DS-8 pages. And there is 2-OP evolution as well (See YAMAHA TG33 page).
YAMAHA DX9 (1983)
YAMAHA DX21 (1985)
YAMAHA TG33 (1990)
Back
Next 
DX7
Deep Synthesis: Home12. 8. 2005