Hi Stuadh

> As to using different power boards, I'm assuming that this

refers

> to separate distribution boards, and not different PSUs I can

easily install another

> dist board for the "noisy" modules.

Actually that should solve the problem: 1 PSU to power the distrib.
boards for "clean" modules and another 1 for the "dirty" ones. Just
crossing my mind what your cap querry earlier might refered to: on
the Oakley distr. board 2 separate ground rails are connected
through a 470nF cap but this is of no help with the Doepfer board
since here all 6 ground pins are already connected on the board's
pcb. Regards, Ingo

> Stuadh
>
> --- In Doepfer_a100@yahoogroups.com , "Andrew Ison"

<andrew.ison@n...>

> wrote:
> > Hows about live components touching the earthed rack itself
> > ----- Original Message -----
> > From: stuadh
> > To: Doepfer_a100@yahoogroups.com
> > Sent: Friday, December 03, 2004 11:02 AM
> > Subject: 1 Re: Power Source interference
> >
> >
> >
> > 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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