Shop by era
Early MIDI era
These synths shipped with MIDI, from the first wave in 1983 to the end of the decade. Sequential's Prophet-600 and Roland's Jupiter-6 were the first instruments released with it, the TR-909 was the first MIDI drum machine, and Yamaha's DX7 put MIDI in front of hundreds of thousands of players. Analog makers kept going too, with Roland's Juno-106 and Oberheim's Xpander and Matrix-12. Early MIDI could be basic. Vintage Synth Explorer describes Roland's first try, on the JX-3P, as very basic. Ask the seller to show the synth playing from a MIDI keyboard, and check it handles what you need, like program changes or velocity. A standard five-pin MIDI cable into a modern interface is all it takes to hook one up.
9 models

Roland · Analog polysynth
Roland Juno-106
1984–1988 · 6-voice polyphonic
Asking $1,975–$2,425 on eBay

Roland · Drum machine
Roland TR-909
1983–1984 · 11 drum voices
Asking $6,825–$8,025 on eBay

Oberheim · Analog polysynth
Oberheim Matrix-12
1985–1988 · 12-voice polyphonic
Asking $18,500–$19,625 on eBay

Oberheim · Analog polysynth
Oberheim Xpander
1984–1988 · 6-voice polyphonic
Asking $5,475–$7,125 on eBay

Sequential Circuits · Analog polysynth
Sequential Prophet VS
1986–1987 · 8-voice polyphonic
Asking $7,075–$8,675 on eBay

Sequential Circuits · Analog polysynth
Sequential Prophet-600
1982–1985 · 6-voice polyphonic
Asking $1,950–$2,125 on eBay
Sequential Circuits · Analog polysynth
Sequential Prophet-T8
1983–1986 · 8-voice polyphonic

Yamaha · FM synth
Yamaha DX7
16-voice polyphonic
Asking $625–$1,000 on eBay

Yamaha · FM synth
Yamaha TX81Z
8-voice polyphonic
Asking $270–$400 on eBay