[sdiy] paia modular 4700 keyboard

[greg montalbano]

Digitally encoded scanning keyboard.
Actually, that's what many of the old PAIA units used.
I can try to throw together some scans of the old Simonton article;
you might want to check first at Anders Sponton's website -- many fine
PAIA manuals online.


At 09:41 AM 12/19/01 -0800, you wrote:
>so i got everything working on that paia, just needed
>a little cleaning and stuff.  now im thinking about
>what to do for a keyboard.  i have an old broken
>crappy keyboard that has nice keys and a good power
>supply.  if i understand correctly, the keyboard has
>to be powered to output a voltage(correct me if im
>wrong here and elsewhere).  the power supply is 15v,
>and i figure i wont need that much juice, maybe only
>like 5-7v?  how much can those modules take?  for
>constructing the resistor section of the thing, i was
>thinking about what would be the best way to do it.  i
>thought of 2 different ways.
>1. each key adds a trimpot as a voltage divider and
>sends out an appropriate voltage.  the disadvantage to
>this is that if 2 keys are pressed, there are 2
>resistor values added and probably a out of tune note
>played.  the advantage being that each note is
>independently tunable.
>2. each key pressed adds all resisitors from that note
>down.  in this scenerio, multiple keys pressed will
>have no adverse affect, and the lowest note will be
>sounded.  the disadvantage is tuning.  from what ive
>read about peoples trouble with synths, this is the
>way they are setup.
>is there other ways?  any and all comments, advice,
>and pointers will be appreciated.
>also what sort of values of resistors am i looking at
>here?
>another thing im still trying to get my head around is
>the way the trigger works.  this would be a pulse
>trigger that starts the envelope generator.  i think
>the keyboard would create this but i have no idea how.
>
>
>thanks for the help.
>
>Skot Wiedmann
>
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