Yamaha CS80

I have no plan for designs beyond the standard M board at this time.  
I need to proof and verify that the basic voice card works "as 
advertised" so that actually using it to replace broken cards means the 
machine still sounds like a CS-50/60/80.  Later, perhaps I will indulge 
in different filters, more VCOs, etc.

  At the moment, my prototype is an old TX-816 rack frame where the 
TF-1s (DX voice engines) have all been pulled in favor of boards I made 
to test the M board equivalent circuits.  Two M board structures per 
frame card.  I call this thing the CSR-80, because 1) my initials are 
CSR and 2) it is a CS-(R)ack frame-80. ;)  It is not fully operational 
yet, but it does work after a fashion.

  The EGs btw are (lowers voice to a mumble) *digital*, using  PICs and 
calculated rate tables similar to the EG-S chip of a DX voice engine.  
They work very well, and if I didn't tell folks now they're calculated 
envelopes no one would know without back-tracing the circuit. ;)  If it 
was an EG that needed to have decay/release rates longer than 10sec 
(attack rates are only 0.1sec to 1sec as per Yamaha design) then I would 
need more resolution, but this is one area of analog synthesizer voicing 
where the microcontroller makes a definite improvement.  Making a pure 
discrete analog IG00159 EG was taking far too many parts.

Crow
/**/

David Rogoff wrote:
> Hi Scott.
>
> It's good to know you're still working on this!  Any plans for
> additional features beyond the original M-Board?  I'd really like to see
> a Moog-ladder filter on board.  This is one really nice feature of
> Arturia's VST.   Also, two, tunable VCOs per board would be great.  It
> would let you have much more flexibility than the fixed tunings of the
> Feet selectors and give a massive four VCOs per note!
>
>  David
>
>