Hi Stuadh, guess you're using the Power One HAA series which is
recommended eg by Oakley ! Thus my only hint would be to separate
the power supply strictly for the audio path on one hand and for CV
and trigger/gate sources on the other. That way you have no hassle
with the cap values since there is no connection of two kinds of bus
boards to power your modules. If you've done that already, I hope
someone else is of more help. Regards, Ilanode

--- In Doepfer_a100@yahoogroups.com , "stuadh" <stuadh@h...> wrote:
>
> In my case, I can't really contact Doepfer direct as I'm using a
mix
> of A Sys, Doepfer and homemade modules with a 6U A Sys case and a
6U
> homemade case Power-one PSU). That said, the trouble started
before
> I added any of the homemade stuff and I added the a-146 LFO to the
A
> Sys case. That was the clincher. I agree that the LED may not be
> causing the problems, but in my case, the modulation is clearly co-
> incident with the the LEDs - speed up the LFO/ADSR or whatever,
and
> the modulation speeds up, too. I'm also well within my Ampage
limit
> (by about 3 Amps)
> While I may be wrong, I believe that my cases are correctly
> grounded. I've tested the voltages of the PSUs and they check out.
>
> I was particularly interested in a thread when I first raised
this
> problem here which Julian and others helped with. Then, it was
> mentioned that adding large capacitors across the power rails
might
> help. My questions are:
>
> what sort of value is recommended
> Does a cap have to be added at the end of each distribution board,
or
> is one pair in a system enough
> What type of cap is recommended
> Does it work
>
> Cheers
>
> Stuadh
>
> --- In Doepfer_a100@yahoogroups.com , Bakis Sirros
> <synth_freak_2000@y...> wrote:
> > btw, it is really wierd:
> > i have a modular with 18 PSU's and i have never
> > noticed any interference in the audio outputs.
> > are you sure that all the 6U cases are properly
> > grounded
> > but, of course, you should contact Roland Mayer
> > direct.
> > his email: technik@d...
> > bakis.
> >
> >
> >
> >
> > --- selfoscillate <synaptic_music@y...> wrote:
> >
> > >
> > >
> > > hello richard,
> > >
> > > i'd love to help you, but i can't.
> > > i'm a nut when it comes to electrical things.
> > > maybe you should email the technical
> > > stuff at doepfer directly.
> > >
> > > best wishes
> > >
> > > ingo
> > >
> > >
> > >
> > > --- In Doepfer_a100@yahoogroups.com , "trebcavxx"
> > > <richardbarton@c...>
> > > wrote:
> > > >
> > > > You've highlighted a condition that's been present
> > > in my own 75-
> > > > module synth almost from the word GO - pulsating
> > > modulation in the
> > > > sound output. It occurs to a greater or lesser
> > > degree in virtually
> > > > ALL patches (I have 11 VCOs) - and takesd the form
> > > of a cyclic
> > > > variation in amplitude - usually giving the sound
> > > a "woo-
> > > > woo.......woo-woo........woo-woo" character rather
> > > than a straight
> > > > tremolo effect. As I say, this has happened from
> > > the humble
> > > > beginnings of a single VCO setup. I now have 5
> > > seperate power
> > > > supplies in the cabinet. I'm a bit doubtful that
> > > LEDs are causing
> > > it
> > > > in my case, but would anyone have a cure for
> > > either of our
> > > problems
> > > > I notice the previous mailing has been pretty well
> > > ignored.
> > > > Richard
> > > >
> > > > --- In Doepfer_a100@yahoogroups.com , "stuadh"
> > > <stuadh@h...> wrote:
> > > > >
> > > > > Hi,
> > > > >
> > > > > I've been reading up on interference caused by
> > > LEDs on the
> > > > > power bus in the archives, a problem that I'm
> > > having in my
> > > > > homemade and commercial cases. I've minimised
> > > the problem
> > > > > by strategically placing the offending modules,
> > > but there was
> > > > > some discussion about including large capacitors
> > > between the
> > > > > power rails to help stop this problem occuring
> > > in the first place.
> > > > >
> > > > > Has anyone done this, and was it successful
> > > > >
> > > > > What constitutes a "large capacitor" and what
> > > type. Does the
> > > > > polarity make a difference
> > > > >
> > > > > Yours Aye
> > > > >
> > > > > Stuadh
> > >
> > >
> > >
> > >
> >
> >
> > =====
> > Bakis Siros
> > Parallel Worlds / Polariton
> > Athens-Greece
> > 1 group owner
> > http://www.shimarecords.co.uk
> > http://www.ward12.com
> >
> >
> >
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