Yamaha CS-50 w/ Kenton MIDI SN 2546

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via this eBay listing, also on Reverb

"This Yamaha CS-50 is a classic analog polyphonic synth that delivers warm, expressive tones with rich modulation and filter control. Known as the little brother to the legendary CS-80, the CS-50 carries much of the same sonic character—lush VCOs, a powerful resonant filter, and a smooth, dynamic response that makes it ideal for pads, leads, and atmospheric textures. This particular unit has been upgraded with a Kenton MIDI kit, giving it modern playability while keeping the original sound path fully intact.

The Kenton MIDI retrofit gives you note on/off control, pitch bend, and sustain over MIDI, allowing you to control this analog beast from any modern DAW or MIDI controller. It still functions just as it always has from the front panel—no limitations there—but with the added flexibility to drop it right into a current production setup. The synth is in solid shape, with the original wood panels, keybed, sliders, and case showing honest wear but fully functional. All controls are smooth, all keys and sliders work as expected, and it’s ready to go.

This is a hard-to-find synth on its own, and even harder to find with a Kenton MIDI upgrade already installed and tested. If you’re after vintage analog character with real-world usability in today’s studio, this CS-50 offers a serious combination of tone, playability, and legacy value."