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Vintage Synthesizers

Sequential Circuits · Analog polysynth · Early MIDI era

Sequential Prophet-T8

The Prophet-T8 was Sequential's flagship from May 1983, and the keyboard is the reason to want one. It has 76 wooden keys with hammer action, two optical sensors per key that read how hard you strike and how fast you let go, and polyphonic aftertouch, so pressing into one note of a held chord changes only that note. New England Digital liked it enough to buy T8 keyboards for the Synclavier, and Dave Smith kept one as his main controller for years. Inside it's closer to the Prophet-600 than the Prophet-5, with eight voices built on Curtis chips, 128 memories, a scratchpad sequencer and MIDI from day one. It arrived the same year as the Yamaha DX7 and lost the sales fight to it, and production ended in 1986. Howard Jones and the Thompson Twins played one, and Tony Banks had one next to his Prophet-10. Go for one with every key's velocity and aftertouch working on video, since sensors and voice chips are hard to replace now.

Spec at a glance

Brand
Sequential Circuits
Type
Analog polysynth
Made
1983–1986
Voices
8-voice polyphonic
Keys
76 weighted wooden keys with velocity and polyphonic aftertouch
MIDI
Yes, from launch

What to check before you buy

Each key has two optical velocity sensors, 152 in all, and a failing one leaves a key with uneven or no velocity. The voices use Curtis CEM3340, CEM3372 and CEM3360 chips, and a failure in any one of them gives a bad voice.

  1. 01Velocity: Ask for a video playing every key softly and then hard on a velocity patch. Each key should get louder or brighter by the same amount.
  2. 02Aftertouch: Ask the seller to hold a chord and press into one key at a time. Only that note should change.
  3. 03Voices: Ask for a video playing the eight voices one at a time. All eight should sound and tune alike.
  4. 04Key action: Press each key slowly on arrival. The action should feel even, with no sticking or clacking keys.
  5. 05MIDI: Ask the seller to confirm MIDI in and out work. Notes should play both ways.
  6. 06Packing: Ask how the seller will pack it. A 76-key wooden-key synth needs a proper crate or a well-padded double box.

Find one on eBay

We haven’t been through this model’s listings yet. Search eBay for it and run every listing through the checklist above. Ask for a video of every voice and a note of anything that’s been serviced or replaced.

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