Rare Clef PDSG (Programmable Digital Sound Generator) up for Auction

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via this auction

Via the seller: "I was recently clearing out some BBC Micro stuff and came across this Clef PDSG (Programmable Digital Sound Generator). It was the last product made by Clef. They hoped it would be taken up by Acorn computers, but it didn't happen, and I think they went out of business after that. It was supplied pretty much as seen, as a DIY project. I initially couldn't find any mention of it online, so I've put up a page to commemorate it here, with pictures and sound samples:

http://www.lemontiger.co.uk/clef.html

There's some information about it here:

http://audiotools.com/en_mi_dead_b.html

"In 1982 the company introduced the product it is best known for these days in the form of the Clef Microsynth (Later the B30 Microsynth), a budget 2 oscillator analogue subtractive synthesiser that was the only product sold by the company that was not developed by Mr. Boothman but rather a design originally published in P.E. magazine as a construction article and conceived by Allan Bradford, it is similar conceptually to the slightly more complex Jen SX-1000 and EDP Wasp in that it uses digital electronics to keep down costs but with it come some operational oddities such as the use of a 0.35V/Octave control voltages meaning that the only other synth that it interfaced with was the EMS, but it was cheap and thus sold reasonably well.

Their most interesting product however arrived in 1984 in the form of the PDSG digital synthesiser, Mr. Boothman had become aquatinted with computing equipment during his time at Ferranti but in addition to computers and defence electronics they were one of the bigger British makers of digital IC's at the time, Ferranti was in fact the manufacturer of the fastest and cheapest DAC chips you could find worldwide in the 70’s. Boothman had therefore been experimenting with digital synthesis and sampling (or digitising as it was known at the time) since the latter half of the 70’s, initially working I believe with an Apple II computer but later with other 6502 based platforms. He amongst other things consulted on some of the early sampling equipment such as the Datel kits that were sold as add-ons for popular home computers at the time.

The first products from the company that featured digital electronics were introduced in 1979 but both featured analogue sound generators, the Master Rhythm is a simple programmable drum machine while the Band-Box was a combination of a sequencer, drum-machine, a monophonic synthesiser and a very simple polyphonic synthesiser. The Band Box was mostly intended as an accompaniment instrument but since it was fully programmable unlike typical such boxes it got some use by pop bands, in fact the full programmability may have been its Achilles heel since the better selling such units from Dr. Böhm, Wersi and Elka all featured mostly pre-programmed patterns that were much more user-friendly for amateur musicians that had little or no computer experience.

These 2 products did not sell well although we see the drum machine for sale from time to time, the really interesting product though is the innovative but badly marketed digital synthesiser that Clef Products had been mentioning as early as 1982 but did not release until the latter half of 1984 as the PDSG or the Programmable Digital Sound Generator. The PDSG is a fairly simple 32 oscillator polyphonic digital synthesiser with a built in touch sensitive keyboard housed in a case taken from one of Clef’s electric pianos, the PDSG required a BBC Micro as a host controller. The oscillator architecture of the unit is similar but better sounding than the Mountain Computer Music System used in the Passport Soundchaser and Alpha Syntauri, but the Mountain board had 24 oscillators and in the Soundchaser/Jen only 16 were used for voice generation, the remaining 8 are hardcoded as LFO's, this made the PDSG more flexible than the Apple II based systems and although it was fairly expensive at the time it was cheap on the whole next to professional digital synths and less than half of what the Apple II based systems were retailing for, and that does not take into account that the Acorn BBC B host computer was considerably cheaper than the Apple as well.

However the PDSG failed in the market completely due to being introduced at the same time as another BBC B based synth, the Acorn Music 500 that was a strikingly similar concept except that it was modular, the PDSG had been initially announced as being available in parts with a separate keyboard retailing for 200 pounds, a synthesiser module for another 200 and a comprehensive software package for yet further 200 but when it was shipped it was as a one box complete systems that retailed for 495 UKP including software. The Music 500 on the other hand could be bought with a just the synthesiser module which could be used completely independently due to the presence of a music programming language, an optional keyboard, expander and MIDI interface was available that all in all made the Acorn system ending up costing more than the PDSG when all the needed options had been put together, but the starting costs were cheaper and Acorn had a proper distribution channel whereas Clef did not, and to add insult to injury the bandwidth and waveform capability of the Music 500 oscillators was much better than what the PSDG had to offer even though the architecture of the latter was considerably more flexible, making the PDSG pretty much a doomed effort from the day that the Acorn product was announced."

There's a blog with a little more information about Clef's other products here:

http://elgauchoandres.blogspot.co.uk/search/label/CLEF

...and some info about their B30 on Matrixsynth:

http://www.matrixsynth.com/2008/12/clef-b30.html

This is not an analogue synth though. It's kind of Pleistocene-era virtual analogue, if you like.

I'm listing it in case it's of interest to a collector; I doubt you'll ever see another. It isn't of much use as an instrument, being extremely basic by modern standards. (The software is literally written in BASIC). I was thinking of scrapping it and using the keyboard for Arduino experiments, but because of its rarity it seemed a bit of a shame to dispose of it without offering it first."