Korg 770 (1973–1976)
The Korg 770 is a monophonic, semi-modular analog synthesizer produced from 1973 to 1976. It followed the earlier Korg 700. In Korg's pre-MS series history it sits between the simple, preset-leaning instruments of the early seventies and the patchable semi-modulars that came after.
The 770 packed a good deal into a 19.5" × 5.5" × 10.5" frame, and it weighed a substantial 30 lbs. The voice centered on two VCOs with selectable sawtooth or pulse waveforms. They fed a single self-oscillating 24dB/octave resonant lowpass filter with keytracking. An AR-type envelope generator handled shaping, and one LFO was available for modulation. The 770 also added a ring modulator and sample & hold, which made it more adventurous than many of its contemporaries. There was no patch memory. Instead, the semi-modular layout invited hands-on patching via its CV/gate inputs (1v/oct).
The front panel offered 37 keys, a line out, and a headphone out. Power came from an external PSU. No MIDI, no sequencer, no arpeggiator, no effects. This was very much an instrument of its era.
The 770 is occasionally discussed alongside the Korg 700S, but it is a distinct model. Korg positioned it as a more capable, semi-modular follow-up to the 700 line. It took a different path from the 700S: a single voice with more flexible patching and modulation options. The Korg 700S itself was described in a contemporary review as a compact and popular instrument of the era Sound on Sound (April 1998, p.270).
What's known about the 770 comes mostly from period listings and database entries. Original documentation is scarce, and there's little in the way of contemporaneous reviews or detailed user commentary. No original price has surfaced in the records. The specs that are documented are consistent across multiple sources.
Known Specs
- Monophonic, semi-modular analog synthesizer
- 2 VCOs (sawtooth, pulse width selectable)
- 1 self-oscillating 24dB/octave resonant lowpass filter with keytracking
- AR envelope generator
- 1 LFO
- Ring modulator, sample & hold
- 37 keys
- CV/gate inputs (1v/oct)
- No MIDI, no patch memory, no sequencer, no effects
- Dimensions: 19.5" × 5.5" × 10.5"; weight: 30 lbs
- External PSU
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