1979 Korg Sigma with Original Box & Packaging SN 241784

via this auction

SN 241784

"In original box with original Korg packaging and baize keyboard cover from the suppliers, Rushworth & Dreaper Ltd of Liverpool.

The history of what has been described as ‘perhaps the most unusual Korg produced’ and ‘one of the great monophonics of all time’:

When Korg released the Sigma in 1979, its design and facilities put older preset monosynths to shame. The instrument was a semi-preset which combined a few of the type of voices found on the Roland SH2000 and APR ProSoloist with a quirky synthesiser section.

It was heavily endorsed by Rick Wakeman (who at one time replaced his Minimoogs with four of them) and also used by Keith Emerson, Jean Michel Jarre, Vangelis and Mike Oldfield. Much later, the Sigma was rediscovered and extensively used by Franz Ferdinand on their album "Tonight".

Based around a three octave pressure-sensitive keyboard, the Sigma was beautifully built. It retained the wooden end-pieces and metal chassis from earlier Korg designs, yet the control panel bristled with knobs, rockers and joysticks. Unlike the Korg Lambda and Delta, the look was distinctly hi-tech, in a Star Trek kind of manner. Likewise, the back of the Sigma was busy with inputs for filter modulation, VCO modulation, VCO pitch and trigger IN, and outputs for trigger OUT, and keyboard CV OUT. There were even independent outputs for the two distinct sound creation sections (termed 'Instrument' and 'Synthe') and a headphone socket.

The Sigma is an interesting bi-timbric synthesizer consisting of two sections: a genuine analog ‘Synthe’ and a Preset ‘Instrument’ section. All together, there are 19 presets: 11 for the ‘Instrument’ section which include fuzz guitar, electric bass, clavi, string, flute, double reed, trumpet and hammered percussion, and eight for the ‘Synthe’ section that give variable waveforms (square, pulse, sawtooth) in different pitch ranges (from 32' to 4'). Each preset has its own rotary control to vary its sound characteristics.

The Sigma is unique for its ability to combine the synth and instrument sections for a nicer, layered synth sound or effect. Remarkably and rewardingly, you can layer any or all of the sounds and effects together.

A pair of joysticks add multi-dimensional control. One controls pitch, noise and vibrato and the second edits the low-pass and hi-pass VCF filters. There is also an ‘Effect’ section encompassing Vibrato, Portamento, Sample and Hold, Noise, Key Hold, Multiple Trigger and Ring Modulator (again, each has its own rotary control to vary its sound). Even though it has a switch labelled "Ring Mod," it's actually a cross-mod. It lets you cross modulate between the instrument and Synth sections. The Sigma is also unusual in allowing you to play a quarter-tone scale."