Synthesist Starsky Carr documents the process of upgrading a Sequential Prophet-5 to a Prophet-10 in this video.
The Prophet-5 Rev 4 is Sequential’s latest generation of an analog polysynth, building on the history of the three iterations of this famous instrument. This massively powerful synthesizer reigned supreme as the go-to polysynth for innumerable musicians. It firmly established itself in the highest echelons of synthesizer history.
The same old Curtis 3340 oscillator ICs are used onboard, two per voice, with adjustable waveforms and pulse width modulation.
Oscillator 1 hard sync to oscillator 2, and oscillator 2 has a low-frequency mode that can be used as an extra modulation source. To customize their levels, both oscillators and a white noise source are sent to the mixer section.
The Prophet-5 is a synthesizer collector’s and user’s legend, with a unique sound that grabbed the imagination of a generation of musicians…but now comes the Prophet-10. The Prophet-10 is a 10-voice version of Sequential’s original five-voice analog polysynth. Doubling the voices opens up more sound choices and increases strength. Two real 3340 analog oscillator ICs with triangle, sawtooth, and pulse waveforms with pulse width modulation are used in each of the ten voices. For rich sounds, hard sync oscillator 1 to oscillator 2. Oscillator 2 not only functions as an audio oscillator, but it may also work in the sub-audio range for extra modulation L.
Carr merges the procedure from around a half-hour to 8 minutes.