The Prophet VS was a hybrid 8-voice synthesizer manufactured by

Sequential Circuits Sequential is an American synthesizer company founded in 1974 as Sequential Circuits by Dave Smith. In 1978, Sequential released the Prophet-5, the first programmable polyphonic synthesizer, which was widely used in the music industry. In the ...

and released in 1986. It is notable for being the first synthesizer to use vector synthesis to structure its sound, using a joystick arranged in a "diamond" pattern for oscillator mixing. Its distinctive sound comes from mixing four 12-bit digital single-cycle waves per voice, which are then fed into analog CEM3379/3389 signal processors for filtering and amplification.

Features and architecture

Sound generation

The VS has 8 voices, each one featuring up to four digital oscillators. Each oscillator is chosen from a table of 0-126 12-bit single cycle waveforms, with the 127th selection being a noise generator. Waves 32-126 are programmed into the firmware EPROMs and cannot be externally modified. However, waves 0-31 are the user wave space and can be overwritten with custom samples utilizing the MIDI sample dump standard. Another unique characteristic of the VS is that the user waves can be manually edited with the onboard wave editor, mixing up to 4 waves into a single one or adjusting individual harmonics similarly to

additive synthesis Additive synthesis is a sound synthesis technique that creates timbre by adding sine waves together. The timbre of musical instruments can be considered in the light of Fourier series, Fourier theory to consist of multiple harmonic or inharmoni ...

. Each voice has a CEM3379/3389 analog signal processor which gives voltage control over the filter, amplifier, and panning. Modulation of panning CV utilizing the modulation matrix can create lush moving stereo patterns.

Hardware

The VS uses an 8MHz

Motorola 68000 The Motorola 68000 (sometimes shortened to Motorola 68k or m68k and usually pronounced "sixty-eight-thousand") is a 16/32-bit complex instruction set computer (CISC) microprocessor, introduced in 1979 by Motorola Semiconductor Products Sector ...

as the main processor, along with two 27256

EPROM An EPROM (rarely EROM), or erasable programmable read-only memory, is a type of programmable read-only memory (PROM) integrated circuit, chip that retains its data when its power supply is switched off. Computer memory that can retrieve stored d ...

s for the operating firmware. Besides the usual 7400 & 4000 series logic chips, there are several unique or hard-to-find parts * I-625 Voice Chip x4 - Each unit uses these for Waves A-D. 8 digital oscillators plus noise generator. These are unique to the VS. * 68B01 Keyboard Controller - Scans the mechanical keyboard and calculates velocity values. Also used in the Prophet 2000. * CEM5510 x4 - 8-channel high-speed

sample and hold In electronics, a sample and hold (also known as sample and follow) circuit is an analog device that samples (captures, takes) the voltage of a continuously varying analog signal and holds (locks, freezes) its value at a constant level for a ...

. Used to fake VCAs for oscillator mixing. These are unique to the VS. * CEM5530 x2 - 30-channel sample and hold. Used to fake VCAs for voice mixing. This is a common point of failure, and several aftermarket replacements are available. Also used in the Studio 440 and Keytek CTS-2000. * CEM3365 x2 - Dual DAC multiplier. * CEM3379 or CEM3389 x8 - Analog VCF, VCA, and voltage-controlled panning.

Legacy

After Sequential was acquired and shut down by Yamaha in 1989, Dave Smith and a handful of the development team moved to Korg, where they worked on developing the

Korg Wavestation The Korg Wavestation is a vector synthesis synthesizer first produced in the early 1990s and later re-released as a software synthesizer in 2004. Its primary innovation was Wave Sequencing, a method of multi-timbral sound generation in which di ...

. Yamaha then expanded upon the VS technology to create the Yamaha SY22 and SY35 in 1990, adding

FM synthesis Frequency modulation synthesis (or FM synthesis) is a form of sound synthesis whereby the frequency of a waveform is changed by modulating its frequency with a modulator. The (instantaneous) frequency of an oscillator is altered in accordance wi ...

. In the 2020s,

Behringer Behringer is an audio equipment company founded by the Swiss engineer Uli Behringer on 25 January 1989 in Willich, Germany. Behringer produces equipment including synthesizers, mixers, audio interfaces and amplifiers. Behringer is owned b ...

released two clones of the Prophet VS, a eurorack synth engine called the "Victor" and a miniature version of the complete synth called the "Pro VS Mini". While modernizing the appearance of the joystick for all following vector based instruments, functionally the "diamond" layout has been followed ever since.

Notable users

John Carpenter John Howard Carpenter (born January 16, 1948) is an American filmmaker, composer, and actor. Most commonly associated with horror film, horror, action film, action, and science fiction film, science fiction films of the 1970s and 1980s, he is ...

Prince A prince is a male ruler (ranked below a king, grand prince, and grand duke) or a male member of a monarch's or former monarch's family. ''Prince'' is also a title of nobility (often highest), often hereditary, in some European states. The ...

Trent Reznor Michael Trent Reznor (born May 17, 1965) is an American singer, songwriter, musician, and composer. He came to prominence as the founder, lead singer, multi-instrumentalist, and primary songwriter of the industrial rock band Nine Inch Nails. T ...

* Rush - The VS Choir is featured prominently on the album ''

Hold Your Fire ''Hold Your Fire'' is the twelfth studio album by Canadian progressive rock band Rush, released on September 8, 1987. It was recorded at The Manor Studio in Oxfordshire, Ridge Farm Studio in Surrey, AIR Studios in Montserrat and McClear Place ...

''.

References

External links

The Prophet VS at Sound On Sound