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Vintage synths & drum machines
Vintage Synthesizers

Oberheim · Analog monosynth · Pre-MIDI classics

Oberheim Two Voice

The Two Voice came out in late 1975, one of Oberheim's first instruments that could play more than one note at once. It's two SEMs (Synthesizer Expander Modules) under the control of a three-octave, 37-key keyboard, so each of the two voices has two oscillators and its own filter. The SEM filter is a two-pole design that works as low-pass, high-pass, band-pass or notch, and it's the root of the classic Oberheim sound. It also carries a small sequencer with two rows of up to eight steps. Sound On Sound called the original a bit of a mythical synth, because few players ever saw one, and it was gone by the end of the 1970s. Vince Clarke and Vangelis are both credited as users, and The Prodigy's Liam Howlett used one now and then. Tom Oberheim brought it back as the Two Voice Pro in the 2010s. That's a different instrument, with a velocity keyboard and a 16-step sequencer. On an original, you're paying for two healthy SEMs and a working sequencer.

Spec at a glance

Brand
Oberheim
Type
Analog monosynth
Made
1975–1979
Voices
Duophonic (2 voices)
Keys
37 keys
MIDI
No (pre-MIDI)

What to check before you buy

Each voice is a separate SEM with its own tuning, so the two can drift apart and need calibrating. Any original is close to 50 years old, so have a tech who knows SEMs look it over.

  1. 01Original: Ask the seller for the serial number and the year of the unit. An original dates from 1975 to 1979, and the Two Voice Pro is a 2010s reissue.
  2. 02Both SEMs: Ask for a video playing each SEM on its own with the filter swept. Both should sound full, with no dead oscillator or crackle.
  3. 03Tuning: Ask the seller to play a held two-note interval. The two voices should stay in tune with each other.
  4. 04Filter modes: Ask for a clip sweeping each filter through its modes. Low-pass, band-pass, high-pass and notch should all work.
  5. 05Sequencer: Ask for a video running the sequencer through all eight steps on both rows. Every step should play and change pitch cleanly.
  6. 06Keys: Ask for a slow run up all 37 keys. Each key should trigger both voices as expected.

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.

Search “Oberheim Two Voice” on eBay ↗eBay search

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