[sdiy] Verniers for Patch Recording

[harrybissell]

The "digital" pots could be used for everything... that you could compress into
a 0-5V or 0-3.3V range. By prescaling with opamps... or (as JH might propose
-he has in the past) ... not making the signals larger than they need to be in
the first place
maybe 0.5V amplitude... those digital pots could work fine.  No need for VCAs to
use
them

I bet a lot of you modular people would not be happy with 7 bit resolution...
the pots
on a Prophet V are seven bit...and they zipper noticibly.  Willing to go there
with your
modular.

Pots are reasonably cheap, quiet, etc.

H^) harry

john mahoney wrote:

> Some people wrote:
> >
> > >Together with the counter knobs this will cost
> > >20$ per dial, ouch!
> >
> > >But you are right, this unacuracy is the reason why
> > >finding an old patch is near to impossible.
> >
> > I think that 7-bit resolution on all your controls (except pitch) would
> > make it possible.  But it doesn't sound like anybody really cares.
>
> [paste]
> > Must be that people aren't interested in saving patches.
>
> I'm totally interested in saving patches! I just don't think verniers are
> the answer, certainly not for $20 per knob.
>
> I think we need a programmable digital potentiometer with high precision,
> fine-grained variability, and the proper electrical characteristics for an
> analog synth. We discussed the Analog Devices digital pots about a month
> ago, and people seemed to agree that they were not the answer. Or, at least,
> they are not a drop-in replacement for regular pots.
>
> Could digital pots could work in conjunction with VCAs and inverters? I
> don't have the engineering knowledge to say for sure, but... The current
> crop of digipots (had to shorten it!) can only handle a limited range of V.
> However, can't that limited V can be used to control the gain of a VCA? If
> so, then we're basically there, in my oh-so-humble opinion.
> --
> john (thinking that ignorance is not bliss)