[sdiy] Polyphonic keyboard scanner

[thx1138]

On 8/1/09 11:15 PM, "David G. Dixon" <dixon at interchange.ubc.ca> wrote:

> Thanks to all for the replies.  I am very interested in looking at the
> Oberheim OB-Xa schematic.  Any hints where I might find it?
> 
> Also, I bit the bullet and bought a book on microcontrollers today (at the
> brilliant Powell's Technical Bookstore in downtown Portland, OR -- if you've
> never been, and you find yourself in the area, you really must check it
> out!).  The book is "Programming and Customizing PICmicro Microcontrollers"
> by Myke Predko.  It's nearly 1200 pages, and it came with a PCB in an
> envelope behind the front cover for building a PIC programmer (how cool is
> that?!? -- I've never bought a book with a PCB in it before!).  Get this: it
> was only $22!  And, the project on page 922 is a switch matrix key
> interface!
> 
>> I cloned and upgraded the Tim Orr ETI Polysynth's polyphonic controller.
>> 
>>> http://rubidium.dyndns.org/cag/pdf/etipoly.pdf
>> 
>> There are some mistakes in the poly assigner schematic. I have all the
>> errors noted down somewhere - as well as a detailed section by section
>> break down of what is actually going on. I may try and dig it out if I
>> can find it.
>> 
>> Other things to note: Cyclic assignment, like the OB-Xa, with optional
>> note stealing and switchable total voice number, 1, 2, 4 or 8. Unusual
>> +/-5V buss bar on the keyboard. Linear glide with OTA control.
> 
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I think I still have all of the OB-XA schematics over at the shop in archive
boxes.

I will have the boxes brought out so I can look for them. I know I don't
have them in electronic readable form. Just hard copy.

Regards,

Terry