Unknown Modular Synthetiser

[saint gillis]

Hi, here's an unknown unique modular synthetiser from the 70s (the dates on the ICs are between 1969 and 1974) :


As you can see there are 4 VCOs, a noise generator (white, pink & red), a Ring Modulator, a Sample & Hold, an ADSR+Filter, an ADSR+VCA, an AR+VCA, a fixed multi-mode filter, a LAG Generator, an Offset Processor & a Preamp.

The legend says it was made for Jethro Tull, a J-T cover band bought it, then it spent some time in a garage, it became Brendan Pollard's property, and we bought it to a guy in France. It was brought (by B.Pollard?) to SynthRestore for a repair/update...

The circuits are made on stripboards (I'll post further photos), I ve written schematics, does someone have ideas about who's built this synth? The boards and the pots are made in U.K

The filter is a Moog ladder kind of clone..
Here is the ADSR + Filter :


The ASDR schematic :


The AR :


The VCA :


The Ring Modulator :

The schematic (AD530 based) :


The Variable LAG, Processor & Preamp :

The schematic:

Do you think the prensence of the wire between Preamp and Variable LAG is normal?

The Master circuit with a A440 generator, a reverb circuit and a headphone amp :


And Finally The Noise generator + Sample & Hold, the Sample & Hold doesn't work but some wires are unconnected, any comments would be appreciated :



If these schematic could bring any ideas about who built this synth, where it was made etc I d be glad!

[mosc]

Thanks for taking the time to make such a complete post. It looks like a very nice synth, especially considering it's age. It looks beautiful. I don't have a clue to the maker but maybe someone else can chime in. The schematics are very interesting.

[bubzy]

how does it sound?

[saint gillis]

It sounds really fat, Brendan Pollard used to name it "The Beast", we called it "Elvis"...

[saint gillis]

I made a mistake on the Preamp/LAG/Processor module, here is the right schematic :