Doepfer

Definitely get that case properly earthed first. Even if its not causing this issue, its not safe for you or your equipment. There should be a both crimped and soldered lug on the metal case, held in good contact with a screw and washers which connects to earth. This probably can be done by connecting the PSU ground to the case, but its worth checking that the case actually is electrically connected to the ground pin on your wall socket. Some PSUs with external bricks have a floating ground

> On 12 Jun 2018, at 14:20, Diego Ragnini diegora@free.fr [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> 
> Thanks, the cables are all recent doepfer
> Not sure to know how to do this experiment though I will try. 
> Which GND do you refer to? 
> Just the one of the audio 2 (the source which feeds the A138s) or the multed audio 1 as well?
> Audio 2 is from a DPO mounted on a A-100P9 PSU3
> Audio 1 is from a Bastl Instruments SoftPop, which in the meanwhile went back to the dealer to be replaced for another kind of issue. I had noticed some electricity at fingers while touching the side panels of its case. It probably is not properly grounded, though it shows some sockets for grounding..
> 
> Best wishes,
> Diego
> 
> > Il giorno 12 giu 2018, alle ore 14:54, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> ha scritto:
> > 
> > As external audio signals are involved it maybe a grounding problem. Make
> > sure that the cables that are used to connect the modules to the external
> > signals carry GND (there are patch cables available without GND, as long as
> > one patches within the case no problems occur, but with external signals the
> > GND is missing). And I don't know if all WMD sockets are grounded. In some
> > modules (yes, also in some older A-100 modules :-) the GND of some sockets
> > is not connected as it does not matter if all modules are connected to the
> > same GND.
> > You may try also the following: connect the GND of the A-100LC3 temporarily
> > to the GND of the signal source unit (at the A-100LC3 there should be an
> > unused GND terminal on the bus board). If then the problem disappears it's a
> > grounding issue.
> > It's just an idea. Not sure if this is the reason.
> > 
> > Best wishes
> > Dieter Doepfer
> > 
> > 
> >> -----Ursprüngliche Nachricht-----
> >> Von: Doepfer_a100@yahoogroups.com [mailto:Doepfer_a100@yahoogroups..com]
> >> Gesendet: Dienstag, 12. Juni 2018 14:06
> >> An: Doepfer_a100@yahoogroups.com
> >> Betreff: Re: [Doepfer_a100] Interferences from A-138s into LC6
> >> 
> >> 
> >> 
> >> 
> >> Hi thanks everybody for replying
> >> The situation was vague indeed, sorry, though the patch is very basic
> >> The case is just 1 row (LC3)
> >> As you can see by the colours on the following screenshot, the
> >> multed audio 1 signal (red cable) is slightly affected by the
> >> audio 2 signal (blue cable), as we turn CW the A-138s channel volume knob.
> >> 
> >> 
> >> Nothing else is patched/ engaged.
> >> 
> >> 
> >> I unfortunately have no means nor expertise for measuring anything..
> >> ASAP I will first try installing the multiple on another case.
> >> 
> >> 
> >> Best, Diego
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> 
> >> Il giorno 12 giu 2018, alle ore 10:25, John Hollis
> >> john@hollis.co.uk [Doepfer_a100] <Doepfer_a100@yahoogroups.com>
> >> ha scritto:
> >> 
> >> 
> >> Hi Diego,
> >> 
> >> It does sound like there might be a short between the adjacent
> >> modules. Can you check for that?
> >> 
> >> Thanks
> >> John
> >> 
> >>> On 12 Jun 2018, at 08:57, yahoo@doepfer.de [Doepfer_a100]
> >> <Doepfer_a100@yahoogroups.com> wrote:
> >>> 
> >>> Hello,
> >>> 
> >>> the A-138s is a very simple module (just a standard mixer circuit with
> >>> operational amplifiers) and I have no idea how the signal could
> >> crosstalk to
> >>> any other module.
> >>> 
> >>> Best wishes
> >>> Dieter Doepfer
> >>> 
> >>>> -----Ursprungliche Nachricht-----
> >>>> Von: Doepfer_a100@yahoogroups.com
> > [mailto:Doepfer_a100@yahoogroups.com]
> >>> Gesendet: Montag, 11. Juni 2018 15:09
> >>> An: Doepfer_a100@yahoogroups.com
> >>> Betreff: [Doepfer_a100] Interferences from A-138s into LC6
> >>> 
> >>> 
> >>> Hello, I have a WMD buffered multiple which suffers from A-138s
> >>> mixer interferences, both powered by an LC6 Doepfer case. Is the
> >>> WMD faulty or its cable? A-138s output can be heard on the WMD,
> >>> unless knob's fully CCW. I also see that the multed signal is
> >>> louder that the original one. Any hint is welcome.
> >>> 
> >>> Best regards,
> >>> Diego
> >> 
> >> 
> >> 
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