[sdiy] CS-60

[The Old Crow]

On Thu, 15 Aug 2002, Dave Magnuson wrote:

> I haven't worked on a CS-60 in particular, but you can add simple MIDI
> (pitch / gate) to *most* synths by driving the keyboard matrix with a
> MIDI->Gate device.  I'm certain I've seen DIY MIDI->Gate projects for
> many sizes of keyboards, and there's probably some commerially available
> units as well.  You're basically fooling the CS-60 into thinking you're
> playing the keys when the notes are actually being driven by MIDI
> events.  I may do this on my Polysix

  The CS-50/60/80 key encoding is a little esoteric.  All of them use an 
'octave select' line and 12 note lines, wired directly from the key 
encoder half of the key assigner to the switches/diodes.  Thus, you will 
want to wire an analog switch matrix in the same fashion: 5x12+1 (C1 has 
its own note line).  This is what the Kenton MIDI kit does.

  Personally, I am very hesitant to solder to traces that go directly to 
the custom key assigner chips.  So much so that my CS-80 retrofit from 
Kenton is still sitting in the box while I work on a new circuit board 
that replaces the KAS board completely, using a nice PIC18F24x-series 
controller.  Then I can just have MIDI on one of the PIC's serial ports.
The trick to this whole endeavor is emulating the odd behavior of the key 
assigner so that the "CS-ness" is not lost.

> If you're looking for full MIDI control of all parameters, then it's a
> much more serious endeavour.  Let the list know what you plan to control
> via MIDI, and we can offer some links and pointers.  If you need the URL
> for a DIY MIDI->Gate project, let me know and I'll try to dig it up for
> you (and let me know how many keys are on a CS-60!).

Actually, it is not that bad for a CS machine.  While I've not done it yet 
(KAS replacement comes first), I should be able to intercept the front 
panel controls with a board of my own that when active, sends its own 
settings (probably from my new KAS board over a sort of internal LAN) such 
that MIDI parameters can alter the CVs.  I figure a handul of those 
99-step 10K serial-controlled pots would make a good control system.  Of 
course, for completeness it would be nice to digitize the front panel so 
that program patches could be done on the machine itself, then saved to 
the voluminous data flashrom of the PIC.


Crow
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