Yamaha CS80

> 	faxiomas@... <mailto:faxiomas@...>
> February 7, 2011 12:46 AM
>
>
> Hi David
> You should look at a previous step than the SH, which is KAS
> itself:  basically you should look at the processing of pitch CV as
> serial and monophonic; the polyphony is helped by the gates straight
> into the SH, while the KAS internally makes possible to distinguish
> between the busy and the avaliable voices; this lets you have polyphony
> and mono unison according to the avaliable notes while in S-2...
> truncating notes...well it is a myth: you actually don't truncate
> anything but if you set long release for the envelope and at the same
> time you have *all* the gates in the SH open, you will definitely
> "hear" the monophonic allocation of the pitch, because the envelopes
> are still running...

Thanks Max - that makes sense.  So, if you have a chord with a long 
release time and let go - and then hit another key - the previous notes 
do not get cut off, but the KAS assigns them all to the new key value so 
you're getting a semi-unison mode.  I wish I still had my little LED 
board to show the trigger signals.  One of those - plus another for the 
KAS gates - would be cool to watch in this mode and make it clearer 
what's going on.

The KAS is a wild and crazy chip!  It has all sorts of strange behaviors 
like this and the "note 8 won't play unless another key is held down".   
It would be great to replace the KAS/SH/TKC boards with a simple 
FPGA/PIC that would make things work more logically and also add a bunch 
of features like unison (which would also be handy for tuning!), MIDI 
in/out, keyboard assignment modes like the Oberheim 4/8-voice, etc.  I 
know there were a couple of folks looking into this kind of 
mod/upgrade.  And where do you stop?  I could see tossing everything but 
the card cage with the analog boards and the panel with just a big new 
board to drive it from MIDI.    It's just a lot of work for a 
35-year-old keyboard with only about 400-500 still alive.   But it would 
look and sound cool as hell next to the new Oberheim SO4V!

We now pause while many folks in the group have their faces glaze over 
and start drooling thinking of this :)

  David


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