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
Rose Specs
December 13, 2009 @ 10:46 pm
Got one recently and i love it... warbles beautifully with that wacked out aftertouch. Its messed up in a really good gritty semi inconsistent way... i'd be very surprised if any digital simulation could come even remotely close to it's reality. To me the Sigma has great presence, movement and wildness when multiple instruments and oscillators are blended/cross modulated but its a bit weak with just a few osc engaged. Raw, full of character, the joysticks rule, metallic capability, multiple attack/release options produce wickedness. A really unique pleasure.
September 22, 2009 @ 7:37 am
punk of a synth . i like this one as you can lose track of time on it. its great for messing around on.intreasting sound on sound article about this one.dont know if i would buy one when you could save up a little bit more and buy the likes of a yamaha cs 10 before they go through the roof.all in all a good synth but not much balls.
March 21, 2009 @ 6:36 am
this is a very weird and wonderful synth one that deliver the promise that analogues often suggest but very seldom deliver, this one comes up with the goods and is totally unique.
March 5, 2009 @ 11:15 am
Unique synth!!..
Ok its ugly and intended by Korg to be used by the home organ/keyboard player but forget about that....
It has GREAT sound potential and expressive control via 2 joysticks..Mix and match some presets and filter settings and boom you are in MS10/20 PS3100 heaven..
Most electronic parts and filters are the same as the better known Korg Analogs so expect the same sonic quality...

The Sigma is "like it or not" a rare machine and if you are looking for a good sounding, quirky looking device than this is your choice...
Jaume Torres
February 7, 2009 @ 9:14 pm
I have a Sigma Synth. I just love it! Easy to program sounds that you can´t forget. Play it and have a great experience!
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User Rating

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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