Korg Sigma

Korg Sigma Image

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 on it that give a variety of sounds. There are 11 presets for the "Instrument" section which include fuzz guitar, electric bass, clavi, string, flute, double reed, trumpet, hammered percussion, etc. And there are 8 presets 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 sounds. The Sigma is also unique for its ability to combine the synth and instrument sections for a nicer, layered synth sound or effect. While the synth section is nice, the instrumental sounds (tuba, trumpet, strings, guitar, etc.) are pretty darn bad, and only get interesting when mixed with the "Synthe" section sounds.

Cool joysticks add multi-dimensional control. Use one to control pitch, noise and vibrato and use the second joystick to edit the low-pass and hi-pass voltage controlled filters! There is also an "Effect" section which is for Vibrato, Portamento, Sample and Hold, Noise, Key Hold, Multiple Trigger and Ring Modulator (each with it's own rotary control to vary it's 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.

Ultimately, however, a basic design, limited edit-ability and a pure lack of memory and MIDI leave the Sigma far behind on the evolutionary scale (although it does let you play a quarter-tone scale). The Sigma has a metal music stand that slides out the back to hold your sheet music suggesting it may have been aimed at hobbyists, though it has been used by Jean Michel Jarre, Rick Wakeman and Keith Emerson. One user describes the Sigma as, "An absolutely terrible keyboard, that is utterly fantastic!"

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32 Visitor comments
January 20, 2013 @ 2:40 pm
An extreme versatile synthesizer, very rare and also very exotic sounds. It sounds very cold and agressive. Some clean (!) demo sounds on the tastronauten website and also some very nice pics (below the banner).
marq lativ
November 17, 2012 @ 7:28 am
Very easy to use, great for detuned solos, need outboard effects, different sounding than a ms 10 or ms 20, editing is very direct and limited, raw oscilator, good filter, pre-programmed resonance, CV Midi possible with Filter and LFO input, i use it very often for doubleing tracks, or synbrass multiple recordings, great beast
June 5, 2012 @ 4:45 am
There is one in my "studio" which i play occasionally. The cross modulation is a monster ;)
Nice lo-fi MS-10/20 like sound...
February 19, 2012 @ 7:26 pm
I've had this thing for a couple of weeks and it's a bit of a one trick pony.

a nice trick is to put the synth and instrument mono outputs to a stereo channel and find the sweetspot where they sound similar enough to make it one big stereo sound. it can sound awesome.

very nice for example for big screaming electro house basslines...

the filter/vibrato/noise joysticks + the aftertouch+portamento are the heart of making this thing really stand out and makes it super expressive.

very fun synth, also very limited, if you've got the space for it+get it for cheap, go for it.
November 14, 2011 @ 1:44 pm
Got it for $100 from a local classified website. I was 5-6-7th on cue & didn't expect that the seller would call me back , but he did called.
My sigma came with sound missing on couple of keys, however it took a year to figure out what happened & fixed it myself .
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Rated 4.44 (806 Votes)

  • Check Price
  • The link above will take you to an eBay search for this synth to see active listings. If you don't find it there, try looking in our forum marketplace or post a wanted classified.
  • Demos & Media
  • YouTube Thumbnail
    Korg Sigma
    by ikworgek

    Audio Clip 1 - Some demo sounds and effects created by the Sigma including effects, wind, modulation and synth sounds.

    Manual - Here is a link to the Sigma's manual. The manual is available as scanned JPG files.

    Brochure - PDF of 1980 Korg Brochure, submitted by Niels Kloes

  • Specifications
  • Polyphony - Monophonic (Bi-timbral: 2 different sounds at the same time)
  • Oscillators - Synth and String sections with a total of 18 VCO's. Sawtooth and Square waveforms along with PWM and noise are available in the "Synth" section.
  • LFO - Vibrato
  • Filter - 12dB/oct Low-pass and Hi-pass with 'Joystick' controller
  • VCA - Attack / Decay
  • Keyboard - 37 keys
  • Memory - None
  • Control - CV, Trigger
  • Date Produced - 1979
  • Resources & Credits
  • Images from Korg Product Brochure.

    Thanks to Orrin Anderson, Lee Matthews and Richard Easter for supplying some information.

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