Sequential Circuits Pro One

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The Sequential Pro One is a wicked little monosynth! It comes from the same period and genre as the Roland SH-101 and Moog Prodigy. The Pro One was basically Sequential's attempt at taking their legendary Prophet 5 poly-synth and packing it into a compact, inexpensive, monophonic analog synth! It has two VCOs, a great 4-pole lowpass filter, two ADSR envelopes (one for filter), and a compact three-octave keyboard. With a Pro-One, you can easily create punchy analog bass-lines and leads or quirky analog synth effects.

The Pro One is an extremely flexible synth with lots of modulation possibilities (ie: the filter, VCO B and LFO can modulate VCO A or B frequencies or pulse widths, or the VCF). There's also an onboard sequencer, something common on many Sequential synths but not often found on other monosynths of the time. It is very basic, however, storing only two patterns and up to 40 notes max. Also, only pitch info is recorded (and in step time only); you can not assign a note duration to any notes. So it's basically a short melodic sketch-pad...but useful. Also onboard is an arpeggiator which has UP and UP/DOWN patterns.


The Pro One is relatively simple and intuitive to use, fun, educational and responsible for some of the coolest and hardest basslines in electronic music today! It is used by Hardfloor, Überzone, the Prodigy, Cirrus, Fluke, Depeche Mode, Download, Banco De Gaia, Vince Clarke, New Order, Freddy Fresh, Mouse on Mars, Prince, Soft Cell, Richard Barbieri and Sigue Sigue Sputnik.

But since you can't always find one (about 10,000 were produced), or one that works properly... Wine Country Sequential has come up with a solution! WCS has been servicing old Sequential gear for years, as well as selling repair parts, etc. They have developed the Pro One Software Synthesizer Plug-In, an awesome replica of the original Pro One, both in look and sound! It has some added features and is an incredible way to easily add the sound of the Pro One to your music! Another option is the Repro-1. Every detail of the original was captured using component-level modelling technology to create the most authentic model possible. All the subtle characteristics and quirks found in the original are present in Repro-1.

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Demos & Media

SEQUENTIAL CIRCUITS PRO ONE Synthesizer 1981
by
AnalogAudio1
Audio Clip 1 Filtered arpeggios and other sounds of the Pro One, from Future Music CD, issue 108.
Audio Clip 2 This Demo plays four sets of comparison tones. The first tone in each set is an original Pro One and the second tone in each set is the WCS Pro One "survival kit" softsynth.
Night CrawlerThis is a text file outlining some settings for a Sequential Pro-One. Courtesy of Music Machines.
ManualDownload the original owner's manual from SoundProgramming.net.

Specifications

Polyphony - Monophonic
Oscillators - 2 VCOs (CEM-3340 chips): : VCO A saw/pulse, VCO B saw/tri/pulse, Noise
LFO - saw, tri, pulse
Filter - CEM-3320 Filter chips: 4-pole lowpass with Cutoff, Resonance, ADSR Envelope, Keyboard Tracking
VCA - ADSR Env
Keyboard - 36 keys
Arpeg/Seq - Arepg: UP, UP/DOWN patterns, Latch mode; SEQUENCER: 2 patterns of pitch info only, 40 note capacity.
Control - CV/GATE
Date Produced - 1981 - 1984

Resources

Images from Perfect Circuit Audio.

Additional information provided by DAC Crowell.