Can't the MS50 VCF (& VCA) OTA be recreated with handmatched diodes
Don't know what that adds to your production costs, but that'd be one
way around the 3019 shortage. BTW, I've built a pair of MS50 VCFs
using CA3019s. They don't have the greatest CV rejection - it's
either the poor diode matching in the 3019, or it's a bunko OTA
design. Aside from the cv thumps, the filter has a nice sound and
IMO, is a worthy contender to the EMS diode ladder.

Over and out,

Romeo


On Sep 4, 2006, at 1:16 AM, <hardware@...>
<hardware@...> wrote:

> Joost,
>
> the prototype of this filter is already working. But as we have
> only a very
> small quantity of the special diode arrays CA3019 available (~ 20
> pcs only)
> and could not find more of these parts a production of the
> "A-106-2" does
> not make sense at the moment.
>
> But we have not been lazy during the summer and I will reveal some
> secrets
> during the next 1-2 weeks. I'm about to prepare the front panel
> suggestions,
> block diagrams and sound examples.
>
> Best wishes
> Dieter Doepfer
>
> > -----Ursprüngliche Nachricht-----
> > Von: Doepfer_a100@yahoogroups.com
> > [mailto:Doepfer_a100@yahoogroups.com]Im Auftrag von levka0
> > Gesendet: Freitag, 1. September 2006 14:24
> > An: Doepfer_a100@yahoogroups.com
> > Betreff: 1 Re: OT: Korg MS20 filter study
> >
> >
> > Dear Mr. Doepfer,
> >
> > A possible 2nd version of the A-106-1 sounds indeed quite
> interesting.
> >
> > If I remember well, you once mentioned that you might rebuild the
> > MS-50 diode VCF. Is this still on your mind
> > (of course after the work on all other new modules has been
> finalized).
> >
> > Kind regards,
> > Joost
> >
> >
> > --- In Doepfer_a100@yahoogroups.com, <hardware@...> wrote:
> > >
> > > Tim,
> > >
> > > excellent work - though I did not yet read and understand
> > everything.
> > >
> > > To speak the truth the A-106-1 was designed more by trial and
> > error without
> > > that terrific theoretical background.
> > >
> > > If the results of the second version of the MS20 filter are
> > promising we may
> > > consider an A-106-2 provided that you give us the permission
> and no
> > > copyrights are affected. Even if you find out an improvement of
> > the A-106-1
> > > of course I'm interested.
> > >
> > > Best wishes
> > > Dieter Doepfer
> > >
> > > > -----Ursprüngliche Nachricht-----
> > > > Von: Doepfer_a100@yahoogroups.com
> > > > [mailto:Doepfer_a100@yahoogroups.com]Im Auftrag von Tim
> > Stinchcombe
> > > > Gesendet: Mittwoch, 30. August 2006 23:06
> > > > An: Doepfer_a100@yahoogroups.com
> > > > Betreff: 1 OT: Korg MS20 filter study
> > > >
> > > >
> > > > Hi list,
> > > >
> > > > A little OT I guess, but there is a connection through the A-106
> > > > (which partly triggered my interest in this work in the first
> > > > place!). I have spent a lot of time looking at the differences
> > > > between the early and later MS20 filters, and have written
> > a 'report':
> > > >
> > > > http://mysite.wanadoo-
> > members.co.uk/tstinchcombe/synth/MS20_study.pdf
> > > >
> > > > File is about 2.25megs, with much mathematics, but some may find
> > > > something of interest in it.
> > > >
> > > > Next I plan to build examples of both filters and see how the
> > reality
> > > > ties in with the analysis (and one outcome will be to see if I
> > > > can 'tame' the resonance response in the A-106, which is rather
> > too
> > > > much 'all or nothing' for my tastes).
> > > >
> > > > Regards,
> > > > Tim
> > > > __________________________________________________________
> > > > Tim Stinchcombe
> > > >
> > > > Cheltenham, Glos, UK
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > Yahoo! Groups Links
> > > >
> > > >
> > > >
> > > >
> > > >
> > > >
> > >
> >
> >
> >
> >
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
> >
> >
> >
>
>
>

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