Sequential Pro-OneReleased in 1981
Perhaps one of the most powerful and musical monosynths ever, the Sequential Circuits Pro-One is much more than a single voice from the Prophet 5. With a well-implemented modulation matrix, 24db filter, and 40-note step sequencer, the Pro-One sets the gold standard.
Pro-Ones were made with two different keybeds. Some used a membrane contact, with style K37U keys; the more reliable keybeds used J-wire contacts, with style K17U keys. If you are ordering keys or keybed parts, make sure you order for the correct keybed.