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
August 27, 2011 @ 6:36 pm
If there are any rich, extravagant museum curators with no head for money out there, there's one of these on eBay going for $999 + $165 S&H from Tokyo. Don't get caught in the stampede. Oh, and he also has a Delta for $699 + $175 S&H aaannndd... a Trident going for the low, low price of $2,960 + $245 S&H. Woo! Whar's mah checkbook?
Mind you, these are all nice keyboards for their day, but really... The seller has an incredible array of wares, but he's expecting to get original list price for them. I just cannot comprehend anyone buying at these prices.
July 4, 2011 @ 10:32 am
I own one and want to correct some information concerning its specs:
1. There are neither 19 VCOs nor is it just one. In fact there are 2 indepenent VCOs, one for the synth section (consisting of 8 suboscs) and another independent one for the instrument section (consisting of 11 suboscs). All suboscs can be activated simultaneously
2. It can produce very fat and sweeping sounds by detuning synth and instrument section against each other
3. When using different settings for the pitch bend range for synth and instruments you can play 2 different tones at one time with the pitch bend joystick
April 13, 2011 @ 4:42 pm
I find it funny that the article makes note of the Sigma's sheet music stand to conclude that it may have been aimed at hobbyists. I think hobbyists mostly can't read sheet music. On the other hand I know real pro musicians who play from sheet music. "After Crying", Hungarian prog band, is one example. I think ELP also played from sheet when with the orchestra, and Keith Emerson also had a separate screen with the scores in London 2010.
March 29, 2011 @ 6:44 am
Tried one of these, fun if you can get it for less then $100 and dont mind carrying its too-heavy self home but not flexible enough for any mediocre0ly involved synthesis and I personally would not invest any money into it.some presets sound ok but you cant tweak it to get whatever variety of sweetness you do love. the programability has the appeal that one gets when playing some weird old organ in their grandparents living room...but it gotboring after 3 hours of fooling around.
March 12, 2011 @ 4:48 am
I borrowed one from a friend and I must say that this synth can sound pretty fat. Nice to fool around with !
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User Rating

Rated 4.44 (808 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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