[sdiy] digital control of CV

[jure zitnik]

sampa - (yep, it's me ;) - why do you say s&h muxes are obsolete?
what's a "patch mode"? i'm not really interested in having encoders in
the system, i've been looking into 360deg potentiometers though...

tom - wouldn't that be much more expensive? how many CV channels do
you plan on having? also, you'd probably need more accuracy than 8-bit
for VCO control, right? well, there's also 12-bit version which would
probably do... but if i understand correctly... this "octal" DACs are
essentialy really nothing more than a single DAC followed by... a s&h?
do i read it correctly? anyhow, it's a neat looking chip, i wonder how
fast you can drive it.

cheers,
jure

On 9/2/07, Tom Wiltshire <tom at electricdruid.net> wrote:
> Jure,
>
> That's pretty much exactly the scheme I had in mind for my own
> monosynth project. The only difference is that I was thinking of
> using multiple octal DACs (AD5346s or similar) on the output side,
> which avoids the need for sample-and-hold stages and makes the board
> neater.
>
> Regards,
> Tom
>
> On 2 Sep 2007, at 21:25, jure zitnik wrote:
>
> > hi guys.
> >
> > in the recent months i've been toying with the idea to toss a few diy
> > modules in a box, and call it a simple subtractive monosynth. fixed
> > architecture. now i'm thinking it'd be really nice to have it
> > digitally controlled, patch storage and such.
> >
> > now from what i've seen such things are mostly done by multiplexing
> > control knobs, getting the multiplexed control signals (CVs?) in an
> > ADC, enter digital domain (patch store/recall), and then back to
> > analogue through a single fast DAC that constantly cycles over all the
> > CVs. separate modules' inputs each have a sample+hold circuit that
> > samples when that module's CV comes up.
> >
> > am i way off? can anyone direct me to a similar project? i'd love to
> > see how other people did that in the past, i'm sure it's been done
> > many times.
> >
> > thanks,
> > jure
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