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Sequential Circuits Prophet 5

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The Prophet-5 actually contains five individual synthesizers, termed 'Voices." For its principle 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 (VGA) 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 simultaneously-held keys.

Supplementing the basic voice are polyphonic modulation (POLY-MOD) signal routings
within each voice that allow OSC B and the filter envelope generator to function as modulation sources applied to OSC A frequency or pulse width, or to the filter frequency. Finally, there is a single low-frequency oscillator (LFO) and a pink noise source which can be mixed to modulate all five voices, as adjusted by the modulation (MOD) wheel. The PITCH wheel raises or lowers the pitch of all voices by the same

The term "digital-analog hybrid" is often used to describe 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 system has three main functions. First, it solves the problem 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 microcomputer memory even when the Prophet is turned off, thanks to a small battery with a 10- year life. Third, the microcomputer system keeps the ten voice oscillators in tune.

Accessories specifically designed for the Prophet-5 include the Model 1005 Polyphonic Sequencer which allows direct storage of lengthy keyboard sequences, and the Model 1001 Remote Keyboard. For increased performance flexibility, the Model 8 Analog Interface Adapter enables remote control of the PITCH and MOD wheels by two Model St^O Voltage Pedals.


Technical Specifications
Type: Analog
Synthesis: Subtractive
Oscillators: 2
Waveforms: Pulse, Saw Down, Saw Up, Sine, Square, Triangle
Osc Modulation: Envelope, Keyboard, Knob, LFO, Mod Wheel, Oscillator, Pedal, Pitch Wheel, Ring Modulation
Envelopes: 2
Evelope Paramerters: Attack, Decay, Sustain, Release, Monophonic
Filters: 1
Types: 24dB Slope (4-pole), Low Pass, Resonance
Filter Modulation: Envelope, Keyboard, LFO, Mod Wheel, Pedal
LFO: 1
LFO Parameters: Sample & Hold, Saw Up, Saw Down, Square, Triangle
LFO Notes::
Dedicated LFO to modulate the pulse width or pitch of oscillator A
Polyphony & Tuning
Polyphony: 5
Tuning: Micro, Standard
Patches RAM: 120
Patches ROM: 120
Editing: CV, MIDI
Optional SCI Model 800 Digital Poly Sequencer

When connected to a Model 800, the Prophet devotes its fifth voice to the
sequencer: Voices 1, 2, 3, and <* may be played "live" while the sequencer is controlling
Voice 5
Chips and Operating System
Rev 3.3
Case: Keyboard
Keyboard: 61 keys, Non-weighted, Plastic
Controls: Knobs, Switches, Mod - Wheel, Pitch -Wheel
Display Notes: Alphanumerical
Dimensions (WxDxH): 37 x 4 x 4
Audio Output Connections: 1/4" Phone Jack, Mono Out
Audio Output Count: 1
Year Released: 1978
Year Discontinued: 1984
Used By
David Sylvian, Tangerine Dream, Weather Report, Skinny Puppy
Manuals & Documents

Product Links
Company Product Sites:
[+] winecountrysequential.com
MSRP List Price: $3,995 - convert
Used Price: $3,700-$5,000 - convert

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