A polyphonic synth introduced by Sequential Circuits in 1978, the Prophet-5 was the company's first synthesizer, although not its first product (it had marketed a hardware sequencer previously). The Prophet-5 was one of the first polyphonic synths to be priced within reach of working musicians, and one of the first with patch memory.
The Prophet 5 revolutionized the way that polyphonic synths are designed, in two ways. First, most previous polyphonic synths had been designed as fully polyphonic, that is, they had one set of voice circuitry for each note on the keyboard. This was a very expensive way to build a synth, and most such synths actually marketed were string synthesizers, special-purpose synths with very limited voice circuitry designed to produce only a few specific sounds. Sequential reasoned that most players will seldom actually play a huge number of notes at once, and that they could build a synth with a smaller number of complete voices that would suit most players, offer a much wider pallette of sounds than the string synths, and be less expensive to build. Using a scanning keyboard design licensed from E-mu Systems, a microprocessor could detect the notes being played and then assign each note to a voice using a voice allocation algorithm. Relying heavily upon voice component ICs from SSM to miniaturize the circuitry, the works of the P5 could be condensed to fit in the space underneath the control panel.
Second, since the synth already had a microprocessor onboard, the designers incorporated patch memory. The ability to instantly recall patch settings was a boon to live performers, who no longer had to spend time tweaking knob settings between songs and using patch sheets or bits of tape on the panel to help them remember settings. With 40 (later expanded to 120) memory slots, the P5 displaced most other polyphonic synths from live performance. It became an instant hit with synth players, even at a price of $3500 in 1978 dollars. The P5 remained in production until 1985.
(It is worth noting that the Oberheim Four Voice was a polyphonic synth that used a scanning keyboard and voice allocation, had patch memory, and preceded the Prophet-5 by two years. However, the Four Voice did not have fully integrated patch parameter controls; there were some parameters that were not stored in memory and had to be set for each voice individually whenever a patch was changed. Plus, it cost far more than the P5 did.)
Rev 1 & 2Edit
Production of the P5 was divided into several revisions. The Rev 1 (as Prophet aficiandos number them) units were hand-assembled, and it is said by service personnel that no two are exactly alike, the result being that many techs will not service them. The Rev 2 was the first mass-production version; it made more use of the SSM integrated circuits to reduce the amount of circuitry required.
In 1980, Sequential redesigned the Prophet to use ICs from Curtis. The reasons why are unclear; the stated reason was that some of the SSM parts had reliability issues. This may have been true, but it is also true that at that time Sequential was about to initiate a patent dispute over the scanning keyboard with E-mu, which owned an interest in SSM at the time. This redesign became the Rev 3, and these units sound somewhat different from the earlier ones. The Rev 3 is further subdivided into the 3.0, 3.1, 3.2, and 3.3 versions. The 3.1 introduced the patch editing paradigm used by most synths with patch memory today, in which moving a panel control instantly edits the associated parameter; in previous revisions, the performer had to select an "edit mode" to change patch parameters. Also, the 3.1 revision introduced a remote control bus, intended for use with the Prophet Remote keytar, but later useful as a convenient hook for easily adding MIDI retrofits. The 3.3 was the final version, and some of these had MIDI installed at the factory.
The Prophet 10 moniker applies to two different ten-voice variations produced by Sequential. The first was basically a P5 with five additional voice circuits installed, for additional polyphony. This model had severe thermal problems, and Sequential eventually re-purchased most of them from the buyers, scrapping them and using the parts in other synths. The second version became the definitive article, a two-manual extravaganza with additional modes for dividing and layering the voices between the manuals. This was also one of the first multitimbral synths, as each manual could be set to play a different patch. All of these P10s are based on the Rev 3 P5 circuitry.
Dave Smith Instruments Revives the Prophet NameEdit
In 2008, Dave Smith Instruments introduced the Prophet 08, a successor to the Prophet line. The Prophet 08 includes two DCOs per voice, a step sequencer, an arpeggiator, and greatly expanded modulation possibilities. Dave Smith was a co-founder of Sequential Circuits and contributed greatly to the design of the original Prophets.