[sdiy] Prophet VS a phase accumulator design

[Scott Nordlund]

> > (I believe the designer's name is Wilfried Dittmar, maybe I
> > should try to bug him about it).
>
> Which of his patents are wort studying/of importance?
> http://www.google.com.tw/patents?tbm=bks&tbo=1&q=Wilfried+Dittmar&btnG=Search+Patents

I think Dittmar was the main designer at Wersi. Of the patents that I've seen, 4572048 and 4644840 cover the DMS digital synthesis engine (it's not much of a revelation). 4096778 covers the Wersivoice chorus circuit, but this is just a standard 3 BBD string chorus with optional feedback/feedforward paths and speed control. There are technical manuals that better describe the same material, but I wouldn't call it a thrilling read in any case. The MK1 and EX20 do some very interesting things (crude formant synthesis and the strangest envelope generators ever conceived), but this is all done in software. The hardware designs are curious but probably not worth studying on their own. Some organs used up to 25 or so microprocessors in a card cage, including an extremely crude MC6809-based "reverb", and the analog Wersimatic CX1 had some pretty odd analog drum sounds (I need to find one of those!). But I don't think most of it is very helpful or informative in 2011.

Well, I'm working on a big writeup with lots of technical info and sound demos and stuff.