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"KORG MS-03: Identical to the MS-20's "External Signal Processor"
This amazing little device translates audio into voltage to control both Hz/V (Korg, Yamaha) and V/Oct (Roland, Moog, Octave, Arp, etc.) analog synths. What's more, it outputs positive and negative gate signals, ENV follower voltage, and has built-in portamento. I used it to make automatic bass lines from drum machine beats and to sweep a Frostwave Resonator filter from the envelope follower. For more in-depth reading on the MS-03's functions, the manual can be
found here. The item functions perfectly and runs on US voltage. I have tested it on a Roland SH-2 and a Yamaha CS-15."