Doepfer

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
> [Doepfer_a100] group owner
> http://www.shimarecords.co.uk
> http://www.ward12.com
> 
> 
> 		
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