MIDI > CV

[gstopp at fibermux.com]

     I looked up the DAC8426 in the AD databook. It's a quad 8-bit linear 
     DAC with parallel input (8 bit data bus plus 2-bit address and write 
     strobe) and looks real similar to the AD7228 octal parallel input DAC, 
     which I've used.
     
     (You mention "serial in" - when I see this I think of serial DACs 
     which have one bit serial data input plus clocks, which are typically 
     used for audio ADC/DAC conversions for CD players and DATs and aren't 
     well suited for low frequency control voltages.)
     
     Anyway I set up the AD7228 to be controlled by a PC printer port, and 
     it works great. I would totally recommend using Analog Devices DACs 
     for analog synthesizer control, as long as you are willing to pay for 
     the rather expensive chips. However you do save a lot of time on 
     building complexity and there's a price on that too which you'd be 
     saving.
     
     You may need to scale the analog outputs to drive standard synthesizer 
     inputs, since the DAC resolution will probably not be 1/12 octave per 
     step even if you tie the LSB low and use the top 7 bits (which would 
     give you note 0 to note 127, about ten octaves).
     
     However if you are going to build your own analog modules to be 
     receiving the DAC voltages, you can leave the scaling part out of the 
     DAC and put it in the analog stuff. This however means you can't 
     control commercial synthesizers as easily.
     
     As a matter of curiosity, how much do the DAC8426 chips cost?
     
     - Gene
     gstopp at fibermux.com


______________________________ Reply Separator _________________________________
Subject: MIDI > CV
Author:  wdc4 at cornell.edu at ccrelayout
Date:    5/21/96 8:27 AM


Is someone out there familar with the Analog Devices "dac - 8426 "   8 bit 
serial in voltage out, w/ 10 volt ref.
     
I would like to interface some of the analog modules we have in the studio 
that the students have built with the Macintosh. This would allow me to 
develop a easier graphical interface and repeatability for the students,who 
I get for an amazingly short amount of time. I'd like to get them "jazzed" 
about analog synthesizers in as short as time possible by meeting them 
halfway, analog modules that we can build together, with computer control 
that they can develop small programs to run.
     
Anyone interested in this project let me know; I warn you ,I'm not an 
electrical engineer, I just deal with sound design for the theatre.
     
Thanks,
     
Warren Cross
T.P.M.
Cornell Univ.Thr.Dept.