[sdiy] DACs for Arp-style quantizer

[Tim Parkhurst]

On 1/31/06, BrightBoy <jdec at mindspring.com> wrote:
> >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.
>
> I agree.  Plus extending the circuit for multiple quantizing channels is
> quite trivial.
>
> Just make sure you use some of those 0.1% resistors from Mouser in
> the DAC ladder in order to make it as accurate as possible....
>
> Cheers,
>
> Jeff
>

Good advice. Also, here's a link with a nice explanation of the
quantizer, and a link to the schemos. (watch for the word wrap on the
URL)
http://www.physicsenterprises.andrews.edu/diy_archive/schematics/sequencers/miniseq/

Tim (doin' the word wrap rap) Servo
--
"Imagination is more important than knowledge." - Albert Einstein