[sdiy] paia modular 4700 keyboard

Fri Dec 21 21:20:09 CET 2001

thanks,  
id love to see the scheme for the keyboard.  i have
the dac so thats definitely a possibility.  thanks for
the help.  

Skot

--- Lewis Bupp <lbuppii at hotmail.com> wrote:

<HR>
<html><div style='background-color:'><DIV>
<P>Skot- I have a 4700 that uses an 8780kbd ( I think)
and a 8782A DAC. I am in the process of rebuilding
mine. I have schemos and some other data if you need
help getting it going.</P>
<P> </P>
<P>Lew<BR><BR></P></DIV>
<DIV></DIV>
<DIV></DIV>>From: male man <FLANGER_MAN at YAHOO.COM>
<DIV></DIV>>To: synth-diy at dropmix.xs4all.nl 
<DIV></DIV>>Subject: [sdiy] paia modular 4700
keyboard 
<DIV></DIV>>Date: Wed, 19 Dec 2001 09:41:07 -0800
(PST) 
<DIV></DIV>> 
<DIV></DIV>>so i got everything working on that
paia, just needed 
<DIV></DIV>>a little cleaning and stuff. now im
thinking about 
<DIV></DIV>>what to do for a keyboard. i have an
old broken 
<DIV></DIV>>crappy keyboard that has nice keys and
a good power 
<DIV></DIV>>supply. if i understand correctly, the
keyboard has 
<DIV></DIV>>to be powered to output a
voltage(correct me if im 
<DIV></DIV>>wrong here and elsewhere). the power
supply is 15v, 
<DIV></DIV>>and i figure i wont need that much
juice, maybe only 
<DIV></DIV>>like 5-7v? how much can those modules
take? for 
<DIV></DIV>>constructing the resistor section of
the thing, i was 
<DIV></DIV>>thinking about what would be the best
way to do it. i 
<DIV></DIV>>thought of 2 different ways. 
<DIV></DIV>>1. each key adds a trimpot as a voltage
divider and 
<DIV></DIV>>sends out an appropriate voltage. the
disadvantage to 
<DIV></DIV>>this is that if 2 keys are pressed,
there are 2 
<DIV></DIV>>resistor values added and probably a
out of tune note 
<DIV></DIV>>played. the advantage being that each
note is 
<DIV></DIV>>independently tunable. 
<DIV></DIV>>2. each key pressed adds all resisitors
from that note 
<DIV></DIV>>down. in this scenerio, multiple keys
pressed will 
<DIV></DIV>>have no adverse affect, and the lowest
note will be 
<DIV></DIV>>sounded. the disadvantage is tuning.
from what ive 
<DIV></DIV>>read about peoples trouble with synths,
this is the 
<DIV></DIV>>way they are setup. 
<DIV></DIV>>is there other ways? any and all
comments, advice, 
<DIV></DIV>>and pointers will be appreciated. 
<DIV></DIV>>also what sort of values of resistors
am i looking at 
<DIV></DIV>>here? 
<DIV></DIV>>another thing im still trying to get my
head around is 
<DIV></DIV>>the way the trigger works. this would
be a pulse 
<DIV></DIV>>trigger that starts the envelope
generator. i think 
<DIV></DIV>>the keyboard would create this but i
have no idea how. 
<DIV></DIV>> 
<DIV></DIV>> 
<DIV></DIV>>thanks for the help. 
<DIV></DIV>> 
<DIV></DIV>>Skot Wiedmann 
<DIV></DIV>> 
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