Korg Sigma vintage analog synth

via this auction

"Pre-set synth by Korg circa 1970s. 11 "instrument" presets and 8 "synthe" tab presets. Plenty of info available on the www. Mono out together with various input and output jacks on the back for VCO, envelope and filter. The names of the instrument voices only are suggestive of real instruments, however one can obtain interesting and unusual sounds by mixing them together. The joysticks are particularly effective, you can control both simultaneously with your thumb and little finger on your left hand, e.g. the pitch bend for an instrument voice and the filter frequency for a synthe voice. This creates some pretty psychedelic effects. The sample and hold on the synthe section sounds particularly effective. The filter on the synthe section also sounds particularly effective, supposedly it is based on the MS-20. Here are some caveats for this particular instrument: the "trumpet" instrument voice and the "hammered percussion" instrument voice do not appear to work. The "mix" dial between the instrument and synthe voices is slightly scratchy. The two joysticks do not have knobs on the top. I cannot discern the functions of the "quarter tone," "multiple trigger" or "keyboard sensor" tabs on the FX bank; they may work in connection with the jacks on the back, or not work. The light above the "quarter tone" effect control is pushed in. One of the rubber hole-stopper inserts is missing on the back top. There are light scratches to top bottom front back sides as depicted. This may originally have come with a "music stand" attachment; if so, it's not included. There is a slight discoloration on the 3rd "C" key."