A monophonic analog synthesizer introduced by Korg in 1976. Based on the same circuitry as the two-VCO version of the Mini-Korg, the 770 offered a more conventional re-packaging, and some control improvements to make the synth more versatile.
VCO 1 offered five choices of waveform, with triangle, sawtooth, square, pulse, and a pulse-width-modulated (rate controlled by an LFO) pulse wave on tap, or an external input could be selected. The VCO included an octave select switch with six settings, including a 64' deep bass setting. VCO 2 produced only a sawtooth wave, or it could be ring modulated against VCO 2, or any of three varieties of noise could be selected. The tuning could be offset from VCO 1. A blend control allowed the user to select the mix of the two signal sources. Other controls at the right side of the panel allowed the user to apply an "auto bend", or vibrato controlled by a dedicated LFO separate from the main LFO. (There were no pitch or mod wheels.)
The voltage controlled filters were the same low pass - high pass pair used on other early Korg synths, with the two horizontal slide controls labeled "Traveler" for controlling the cutoff frequencies, which could also be controlled via an accessory pedal that connected to the synth via a 5-pin DIN jack. A switch allowed for three possible settings of resonance for the filters; other switches provided settings for how much of the envelope generator and LFO signals should be routed to control the filters. Like other early Korgs, the envelope generator had peculiar controls that effected multiple segments and interacted in ways that were not always obvious, although the 770 did provide more control options than the Mini-Korg.
The 770 was packaged in a case with an angled panel and a 32-note, F-to-C keyboard. It was the first Korg synth to be marketed under the Korg name worldwide, although distribution outside of Japan was still handled by Univox. A badge on the panel in the VCF area identified the synth; early versions read "Synthesizer Korg", while on later ones it said "Korg 770"; the latter marked the first appearance of the stylized "Korg" logo tha tthe company still uses today. This was the beginning of establishing Korg as a brand name rather than just a model name. Two different styles of knobs were used throughout the production run. It is not known how long it remained in production, but it was almost certainly dropped by 1981, when the Mono/Poly was introduced. The 770 was a favorite of the original version of Human League and appears extensively in their early recordings.