Vintage Prophet 5 Rev 3.3 Model 1000 Sequential Circuits Synthesizer w/ Midi SN 4598

via this auction

Update: note the description appears to be pulled from this other listing on reverb. The pics and serial number are different. As always, adhere to eBay's and Reverb's buyer guidelines to protect yourself.

"The Prophet-5 actually contains five individual synthesizers, termed “voices”. For its producible sound sources, each voice contains two voltage controlled oscillators (VCOs), referred to as OSC A and OSC B. OSC A, OSC B, and a white noise source can be mixed into a resonant low-pass voltage controlled filter (VCF). The filter modifies the voice timbre under control of its four-stage envelope generator. The filter may also serve as a sound source. Following each filter, a voltage-controlled amplifier (VCA) also controlled by a four-stage envelope generator shapes the voice amplitude. Only one voice is depicted on the control panel, because the voice controls “patch” the five voices identically. This makes the voices homophonous— they sound alike— with pitch differences corresponding to (at most) five keys simultaneously-held keys. The term “digital-analog hybrid” is often used to described the Prophet. This means that instead of directly controlling the analog synthesizer voices, the keyboard and most controls are actually devices which input “data” to a microcomputer system which in turn “programs” the voices. The microcomputer has three main functions. First, it solves the of generating five independent sets of voice control voltages and gate signals (which operate the envelope generators) from a single keyboard. Second, its digital memory provides a way to store all of the switch and knob settings which form a program. These programs are retained by the microcomputers memory even when the Prophet is turned off, thats to a small battery with a 10-year life. Third, the microcomputer system keeps the ten voice oscillators in tune."