Back to Digisound

[david.peachey at natwestuk.co.uk]

And Dave sang the praises of the Digisound modular synth . . .

< SNIP >

I couldn't agree more with you, Dave.  I started on mine when the articles 
first appeared in Electronics Today International back in 1980 and it was 
being developed and distributed by Charles Blakey in Blackpool (England).  I 
had endless hours of fun building mine (and making a lot of weird and 
interesting sounds) and  got as far as building a system with 35 assorted 
modules (various combinations of CEM and SSM chips) before things went quiet 
when Charles Blakey died and Tim Higham took over (and then eventually 
disappeared without trace).

>  Some modules use SSM chips, I think this is just the Dual Env Gen and the 
Ring Mod, although I think these were later
>  updated to 3310 and 1496 respectively. Or maybe they superseded the Dual 
EG with the VC Env Shaper that uses the 3310.

The original versions of the 80-7 VC State Variable Filter, 80-8 Dual ADSR 
and 80-11 Dual Ring Modulator all used SSM chips.  The 80-7 design was 
replaced with one using a CEM3320/3335 combination (unfortunately the 3335 
doesn't seem to be available at all, now).  The 80-8 was replaced by the 
80-18 Dual EG using two CEM3320s and the 80-11 was replaced by a design 
using discrete components and no hard-to-get-hold-of ICs.  The 80-10 VCEG is 
something else again - an excellent and very flexible module.

>  They were quite popular in Britain once upon a time and still are quite 
sought after.

Too right, the last one which came up or sale in the UK on Peter Forrest's 
VEMIA site went for just under UKP1000 and that only had ten modules.  I 
also recollect another six module machine which went for UKP300 within about 
six hours!  The price for modules seems to start at UKP100 and carry on up 
depending on what module is for sale.

> The mini booklet/stack of A4 pages called Using the Digisound 80 (or 
something like that) is also a very good read.

I've got a complete set of construction articles and the "Using . . . " 
guide plus the original ETI articles (including PCB foil patterns and the 
articles for the earlier SSM-based 80-7, 80-8 and 80-11 modules) as have 
several people to whom I have copied them.  I concur with Steve that it 
would be a good idea to get this all up on the Internet.  If anyone wants a 
set to enable them to do this, drop me an e-mail with a snail-mail address.

>From Paul Schreiber's original message . . .

>  What I'm interested in is what you users think of the sound, compared to 
a (say) P5 Rev 3 or maybe a OBx-a.

Well I couldn't say, not having ever had access to a commercially available 
CEM-based synth but I like because of its fully modular flexibility and the 
ability to plug any output into any input just to see what it can produce 
and, boy, can it produce some wierd noises.

>  What I'm getting at is the following: are the modules worth my time 
bringing back to life. I don't mean in the exact form-factor.
>  But the whole idea of a CEM-based modular.

And from Dave . . .

>  The Digisound is certainly a good candidate for bringing back to life, 
its been loved and cared for by many people for nearly
>  two decade's. Its not totally CEM based, because a lot of the modules 
don't require it. The meat of the system does rely on
>  the 3310/20/30/40 combination though. All in all I think its a good 
system. The chance to build new ones would be excellent.

I've been able to a number chips for my own use (thank you Paul).  The foil 
patterns for many of the modules are still available and I'm working towards 
getting a number produced (not commercially, just through some friendly 
acquaintances) and I've also prepared a (virtually) complete set of front 
panel diagrams in MS Powerpoint (if anyone wants a copy of the file).

All-in-all, I'm pretty much ready to start adding to my existing setup - 
it's just going to take time and a lot of money!  If you're in the UK Dave, 
send me an e-mail and we could compare notes on this - anyone else? - 
provided, of course, Paul continues to have the necessary chips available.

Sorry for the long post, cheers for now

David Peachey
david.peachey at natwestuk.co.uk