[sdiy] DACs for Arp-style quantizer

[Tim Parkhurst]

On 1/29/06, anthony <aankrom at bluemarble.net> wrote:
> I really like the Arp-style quantizewr that uses a staircase generated from
> a DAC. The designs I've seen use 12-bit DACs but I was wondering if an 8-bit
> one wouldn't work, especially since one of the designs that I saw used only
> 8 bits anyway. I don't really care about tracking accuracy because I am
> using it to drive a v/oct flanger array that is being controlled from a
> sample & hold random source. The DACs I have seem pretty nice for this app
> actually: TLC7524 & TLC7528 (same as AD7524 & AD7528). I guess I could push
> on and try something and see. Wouldn't be out anything except time and I
> have plenty of that.
>
>

You might want to take a look at the quantizer used on the Oberheim
mini-sequencer. It's a surprisingly simple 6-bit version and uses an
R/2R DAC. 6 bits doesn't sound like a lot, but it works out to
perfectly quantize a 5 octave range. I wouldn't think you'd need the
extra bit depth unless you really needed the extended range (and even
then, 7 bits would cover just over 10 octaves), or you wanted to do
microtonal scales. I've looked at the schematics for the ARP
quantizer, and I've found the Oberheim solution to be a more elegant
(and simpler) solution.


Tim (needs more bit depth) Servo
--
"Imagination is more important than knowledge." - Albert Einstein