Yamaha CS-15

It features two voltage-controlled oscillators, two 12 dB/Oct multi-mode Voltage-controlled filter (Low-Pass, High-Pass or Band-Pass), two ADSR envelopes and a Low-Frequency Oscillator. It also features a White noise and an external-in for processing other sounds.[6]

The CS-15 offers a great flexibility with various routing possibilities to the filters and envelopes. You can, for example, rout VCO 1 to both VCFs and the VCFs to any of the envelopes positive or negative voltage.

It's actually a duophonic / bitimbral synthesizer but you have to connect it two separate CV/Gate controls (Hz/V like Korg synthesizers not V/Oct) to play the extra voice.

The CS-15 was used by several bands in the early 1980s. The Human League made prominent use of the instrument on their album Dare.[6] Marillion used a CS-15 on their first full-length album, Script for a Jester's Tear.[7] It was also used by Astral Projection, Somatic Responses, Moog Cookbook, The Human League, and Vince Clarke[8]. In post-disco early 80s NYC Boyd Jarvis, through groups like Visual, extended early DJ radio NYC mixes and home made reel to reel music using drum machines and a Yamaha CS-15, began an underground musical movement that later came to be known as house music.

• CS-60
• CS-80