Sequetial Circuits Pro One vintage analog monosynth. Two oscillators with PWM, hard sync, and multiple simultaneous waveforms; four pole resonant lowpass filter; two ADSR envelope generators; LFO; noise generator; sequencer/arpeggiator; extensive modulation capabilities; CV I/O for interfacing with other gear. It is essentially one voice from a Prophet 5.

It has some minor cosmetic blemishes (I bought it new in 1982), but it functions well. I recently calibrated the tuning, and cleaned the pots and keyboard contacts. It has the power supply mounted to the chassis, not the circuit board like earlier serial numbers, and has the j-wire keyboard instead of the membrane type that later models unfortunately had, so maintenance is fairly easy. The only physical issue is that the power switch requires a lot of force to turn on, but it turns off easily. I haven't had a chance to get a replacement switch yet, but it's an easy fix, and the part is only about $5.00, if somebody doesn't want to wait on that to be able to take it home.

Please note that I am selling this item; I am not looking to trade for other equipment. Sorry if this is inconvenient.