hello royce,
i'll try to explain (dieter, please correct me if i'm wrong).
basically the a171 is a dc-coupled lowpass filter,
built around an ota chip. the circuit has to be calibrated
to exact 1:1 amplification in order to maintain the exact
signal level. usually this module is calibrated only roughly
to 1:1 amplification, which is good enough in most cases.
on your a171 this calibration maybe is a bit too rough.
the service manual says that it is possible to calibrate
the a171 so that is works as high precision slew limiter,
but in this case some additional trimmers have to be placed
on the pcb to do this adjustment. this will cause extra costs,
but the service manual also says that these trimmers will eventually
be supplied as standard in the future (my service manual is
more than a year old), so i don't know if you can do the
adjustments yourself. my a171 was not calibrated, but i
have to admit that i don't use my a171 for slewing
pitch cv's, so i cannot tell you that mine works better
than yours.
i suggest that you contact doepfer directly, i'm sure
that they will help you with your a171.
best wishes
ingo
--- In Doepfer_a100@yahoogroups.com, "rrooyyccee" <rrooyyccee@y...>
wrote:
>
> thanks for the reply.
> this is all somewhat confusing. i confess i don't understand the
> concepts at play here, but did have a chance to search for the
> archives, and found some threads hinting that the bussboard module
may
> be necessary to do portamento effects. when i read the instructions
to
> the buss module it says it may be necessary to use it before the
a171.
> but again, somewhat indirectly.
>
> i like the sound of the 171 alot so far, but of course need correct
> pitch. ingo, did you have your a171 calibrated? is it something i
> could do myself? it seems odd to buy a module and then have it
calibrated.
>
> royce
>
> --- In Doepfer_a100@yahoogroups.com, "selfoscillate"
> <synaptic_music@y...> wrote:
> >
> >
> > hello,
> >
> > maybe your a171 is not calibrated to exact 1:1 amplification,
> > this is not an error of your module, afaik it is a side effect of
> > the a171 design. the a171 can be calibrated to exact 1:1
> > amplification, you should contact doepfer directly for
> > more information.
> >
> > best wishes
> >
> > ingo
> >
> >
> >
> >
> >
> > --- In Doepfer_a100@yahoogroups.com, royce <rrooyyccee@y...>
wrote:
Show quoted textHide quoted text
> > >
> > > HI LIST
> > >
> > > I'm having some problems with the doepfer vc
> > > controlled slew limiter and am not sure if they are a
> > > technical problem or not. I'm sending pitch CV in from
> > > an encore expressionist, then CV out to my oscillator
> > > modules (modcan and system 100). It is tracking the
> > > pitch, but not perfectly. Furthermore, when I adjust
> > > the slew rate with the slew rate knob, the pitch
> > > changes several steps in a gradual fashion. To be even
> > > more specific, the pitch increases if I turn the slew
> > > rate up AND if the pitch I'm playing is relatively
> > > high, but does the opposite if the pitch I'm playing
> > > is relatively low.
> > >
> > > I'm using an A.Sol power supply in an A.Sol case.
> > >
> > > Any ideas? Is this intrinsic to all slew limiters or
> > > just my system?
> > >
> > >
> > >
> > >
> > > __________________________________
> > > Yahoo! FareChase: Search multiple travel sites in one click.
> > > http://farechase.yahoo.com
> > >
> >
>