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Sequential Circuits

How many of you are working on a revolutionary piece of electronic hardware in your 'garden shed' workshop, hoping that one day your labours will come to fruition and you'll be running your own design and manufacturing company whose success is based on your backroom invention? Well keep at it — because that's exactly how Sequential Circuits Inc started life.

Dave Smith is the brains behind SCI. He started his career in the music industry from the palatial surroundings of a large cupboard in his bedroom where he designed and made sequencers. This was in 1974, and the exact designation of the product was the Model 600 Digital Sequencer, a device that didn't exactly make him rich, but served as an entree into the synthesiser world. In 1976, he released an updated version of his sequencer — the Model 800, which did start to bring in the bucks, enough for him to invest in some more sophisticated test equipment, to leave his job at Diablo Systems and to concentrate solely on his company — Sequential Circuits Inc.

Designer and President Dave Smith.

His next product was a programmer for a synthesiser (the Model 700) which appeared in 1977. Now this was something really new — it enabled owners of instruments such as Minimoogs, ARP Odysseys, 2600s, and modular synths to be able to predetermine the settings of various parameters and to call them back at a touch of a button. The programmer of 1977 was very similar to those we see incorporated in the synths of today save that the older synths didn't have many voltage controlled parameter settings (i.e. you couldn't vary the resonance of the filter (say) with a CV). This programmer was therefore a bit limited, nevertheless, in order to give it as much control as possible over the final patch, Smith built two voltage controlled ASDR envelopes into the programmer thus bypassing the synth's envelopes but enabling their parameters to be stored in memory — a neat solution.

The programmer brought in even more money, and this was enough to get him started on his main ambition — to build a programmable polyphonic synthesiser that would not be a compromise. In July 1977, Dave Smith first revealed the Model 1000 Prophet synthesiser, which was available in five and ten voice format. Unfortunately it was soon realised that the ten voice module was inherently unstable, as there just wasn't enough room in the instrument's elegant casework to house the extra voices and to maintain an adequate circulation of air. The original Prophet 10 was therefore withdrawn, however there are a handful of these instruments still around, most of which have been 'modified' (at some expense) to maintain their stability.

Prophet 5.

The Prophet 5 was a winner from the word go. It was, and still is, a brilliantly designed instrument, and this is proved by the fact that even after five years it is still one of the best selling polyphonic instruments in production. The instrument features many unique design concepts. It is fully programmable; offers auto tuning (almost unheard of in 1977); and is a true voice assignable polyphonic offering two oscillators per voice. Although the instrument was an instant success story, this didn't mean that SCI didn't have their problems. As any production engineer will tell you, every component in your product must be second, third and even fourth sourced, i.e. if you can't get parts from your usual supplier then have a couple of other back-up distributors readily on hand. Alas, the Prophet was one of the first instruments to use the SSM (solid state logic) synthesiser voice chip set, and inevitably there was a hold up in supplies, and there was only one source!

This put SCI in a most embarrassing situation — they had geared up production to meet the enormous demand for the instrument, then had been let down on a vital part; consequently they were sitting on large numbers of 99% finished units, ready to be shipped, apart from this one (actually the instrument used five) chip. Lessons were learnt from this, and eventually, both for supply and reliability reasons SCI went over to using the Curtis chip set in the Prophet — which they still do.

Pro-Ones under testing.

Two other products were soon to be added to the SCI catalogue — the Prophet 10, a dual manual version this time, with ten voices, a larger programmer and several other rather interesting features; and the Pro-One, a monophonic synth based on a single voice of the Prophet 5. The Prophet 10 wasn't as big a success story as the '5, it isn't as attractive to look at and doesn't really offer the musician (especially the recording musician) enough extra to justify the extra expenditure. The Pro-One, however, has become one of the most popular monophonics around, confounding all the sceptics who said, on its arrival, that the market wasn't big enough to support another monophonic.

More recently, SCI have released the Pro-fx system — a programmable rack mounted effects and audio processing unit. In fact these should just be arriving in the stores as you read this; but the one that everyone has been waiting for since it was initially revealed at the Winter NAMM show in California last January is the Prophet-t8.

Prophet t8.

Sequential Circuits products have been handled in the UK, up until the beginning of this year, only by Rod Argent's Keyboards in Denmark Street, London. They initially saw the potential that the Prophet offered as far back as 1977, and were responsible for importing them directly from the Californian factory. Incidentally, their American Head of Sales is a certain Bob Styles, who was the original manager of Rod Argent Keyboards — not only did he recognise a good product, but also a good company, and he left the UK to work in sunnier climes at the US company HQ. At the beginning of 1982, SCI set up their European headquarters in Mijdrecht (pronounced My-drecked) in Holland. There was hope that the European operation could be based in London, but the Dutch authorities made it financially more attractive to move to Holland. Nevertheless, SCI Europe is run almost exclusively by people from the UK, so if ever you find you need to contact SCI you won't be assaulted by a burst of incomprehensible Dutch — double or otherwise.

SCI's European team is led by Tim Oake, Manager of European Operations, and Tim Salthouse, European Sales Manager (ex. of Rose Morris and Casio). The servicing side is run by two ex-Argents men Steve Garth, European Service Manager, and Paul Tebbut, the resident electronics engineer. Jan Van Leeuwen looks after the accounting side of things, which is quite a task when dealing with US products being imported then re-exported throughout Europe.

The Mijdrecht facility is most impressive, the warehouse is enormous, and one can only deduce that SCI will be adding dramatically to their product catalogue in the near future in order to maximise the potential that such a European base offers. In fact certain 'tie-ups' with other US manufacturers have already been discussed, and we envisage that some news will be forthcoming at the Frankfurt Music Fair in February. In the meantime, perhaps we should finish this profile by taking a close look at the current products.

The SCI Catalogue

The Pro-One: (rrp £450.00) An excellent monophonic (see review E&MM March 82) with two oscillators, noise generator, mixer, 24dB/octave LP filter, 2 x ADSR envelope generator, comprehensive modulation and cross modulation section, 3 octave C scale keyboard, 40 note sequencer, arpeggiator, and a useful selection of interface jacks.

The Prophet 5: (rrp £2,992) This programmable polyphonic has undergone several updates since its inception. Rev 1 Prophets with the power switch on the front are s/nos 0001 to 0182 — these have no cassette interface. Rev 2s (s/nos 0183 to 1301) have the power switch on the back and tune and edit buttons on the front panel in its place. Rev 3s (s/no 1301 to 2469) utilise the Curtis Chips fully, and offer voice defeat and adjustable scaling facilities. Rev 3.2 (s/no 2470 upwards) feature analogue and digital jacks for interfacing the Prophet to a Poly-Sequencer. In addition more recent Prophets have 120 memories as standard as opposed to the original 40.

The Prophet's main features include: 5 voices consisting of 2 x VCOs, Noise, Audio mixer, 24dB/octave LP VCF, 2 x ADSR envelopes, LFO, comprehensive Poly and Mono modulation; programmer; interface facilities, cassette interface; and five octave C keyboard.

The Prophet 10: (rrp £6,185) Essentially a dual manual ten voice version of the Prophet 5, but with additional keyboard assignment modes enabling doubling, alternate and normal voice routing; a programmable equalization section; and an onboard cassette unit with poly sequencer (optional).


The Pro-fx System: A unique rack mounting modular system which enables the musician to preprogram his signal processing. The system consists of Model 500 Mainframe; the 510 Phase Shifter; the 512 Distortion Sustainer; the 514 Mixer; the 516 Parametric Equalizer; and the 518 Reverb Unit. The modules can be combined as desired in the six slot rack; prices range from £170 to £626 for the System Controller.

The Prophet t8: The instrument that is going to take SCI into 1983 with a bang. The t8 features a touch responsive (both velocity and pressure) 6 octave keyboard; it is fully programmable with eight voices which can be layered and split as desired. Final details of the instrument aren't available yet, but it looks as though the t8 is going to be one of the most important new instruments on the market for many years.

The Poly Sequencer: (rrp £925) This is a remarkable multi channel digital sequencer with 10,000 notes storage which can be used in real or step time. It incorporates a built in digital tape recorder for storing program and sequencing information.

The Remote Keyboard: (rrp £638) For those wishing to move around on stage SCI have developed this remote keyboard controller for use with the Prophet 5 or 10. It features a four octave keyboard with conveniently located program selection switches. Also, in the 'neck' of the controller are pitch, modulation and volume performance wheels for expression. All these are housed in a unit weighing less than 10lbs. The Remote Keyboard is linked to the main instrument via a twenty foot multiway cable.

For further details contact SCI, (Contact Details), or (Contact Details).

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Electronics & Music Maker - Copyright: Music Maker Publications (UK), Future Publishing.


Electronics & Music Maker - Jan 1983


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