Description Manual Insta-Set book
The 770 is an odd late-70's Korg synthesizer. Never a big name, but this has been a servicable little beast for nearly 30 years.
The Korg 770 is a two-VCO, monophonic synthesizer with a 32-note (F-C) keyboard.
The two VCOs sit at the top of the panel, one to the left and one to ther right with a mixer section between them. The oscillators can be mixed, ring modulated, or one can modulate the other to create FM sounds. VCO2, the one on the right, can also be a noise generator. The mixer includes a switch to choose one or the other VCO. VCO1 can take external input (like a mic or a guitar) and feed it through the signal path. A very nice feature.
To the left of VCO1 is the LFO speed knob. Below that is the portamento control, with a switch allowing alternation between knob settings and a fixed port speed. Below VCO1 is the filter section. The low pass and high pass filters are in an unusual, and very useful, stacked configuration, and are sliders, not knobs.
This allows you to make intercepting filter sweeps with one hand, and allows you to get to resonance points very easily. The four switches in this section set the ranges for the filters, 'brightness', and how much LFO to add to the filter path. To the right of the filter section is the envelope/trigger section. Only attck and 'singing' (release) are slider controlled. Sustain is set by a 3 postion 'x1 x10 x100' switch.
Triggering switch allows percussive, sustain, and hold. Another exciting enhancement in this unit was the final button in this setion, triggering. Allows VCO triggering by key, LFO, and remote.
Final section, far right bottom, is other mods. Two mods, tremelo and ptch bend. Tremolo does what you would expect, with speed and delay settings.
Pitch bend allows up or down bending, knobs for amount and speed. The control this synth offered was amazing. Unfortunately, the sound didn't live up to the controls. With the best tweaking you could do you still ended up with a buzzy little synth. Fat bass? Nope. Screaming fluid lead? Nope. Little buzzy dude? Yeah.
Note: These two documents look greyish-yellow with age. They ain't. These were greyish-yellow when I got them new in the box in 1977, very cheap paper.Owners Manual