Doepfer

Please can someone check that this would be the right connection in order to grant that the A-100LC3 “GND” is temporarily connected to mains earth/GND? So I would temporarily connect the blade terminal of the first picture to the same blade terminal found in the A-100P9 (2nd picture). Then, in order to set a definitive connection, I would provide a mains “plug" where to pass uniquely cables for all floating GND's in the system towards the mains earth/GND pin wall socket. Would both these solutions be correct, please? 
Best, Diego 






> Il giorno 13 giu 2018, alle ore 09:53, yahoo@doepfer.de [Doepfer_a100] <Doepfer_a100@yahoogroups.com> ha scritto:
> 
> It's not for sure that this is the reason for your problems. So I'd
> recommend just to try it out, i.e. connect the GND of the A-100LC3
> temporarily (e.g. the GND blade terminal on the A-100 bus board) to GND of
> the other devices included in the signal path. If you use an A-100LC6
> (mentioned in the subject of your message) that not necessary as the
> A-100LC6 GND is connected to mains earth/GND.
> 
> Does the problem also occur if you use the A-138s outputs directly (without
> the buffered multiple)?
> 
> Best wishes
> Dieter Doepfer
> 
>> -----Ursprüngliche Nachricht-----
>> Von: Doepfer_a100@yahoogroups.com [mailto:Doepfer_a100@yahoogroups.com]
>> Gesendet: Dienstag, 12. Juni 2018 19:43
>> An: Doepfer_a100@yahoogroups.com
>> Betreff: Re: [Doepfer_a100] Interferences from A-138s into LC6
>> 
>> 
>> Ok thanks, so I have to learn how to ground it !
>> It seems obvious but not
>> I will try
>> 
>> Floating GND (?) needs to be deepened
>> Or I’d better search for someone who can do it?
>> 
>> 
>>> Il giorno 12 giu 2018, alle ore 15:57, yahoo@doepfer.de
>> [Doepfer_a100] <Doepfer_a100@yahoogroups.com> ha scritto:
>>> 
>>> I fully agree. As the A-100LC3 also uses an external power
>> supply it's GND
>>> is not connected to mains earth/GND and has the mentioned
>> "floating GND" (in
>>> contrast to all other A-100 cases).
>>> 
>>> Best wishes
>>> Dieter 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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>>>>> 
>>>>> 
>>>>> ------------------------------------
>>>>> 
>>>>> Yahoo Groups Links
>>>>> 
>>>>> 
>>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>>> 
>>> 
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>>> Yahoo Groups Links
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>>> 
>> 
>> 
>> 
>> ------------------------------------
>> Posted by: Diego Ragnini <diegora@free.fr>
>> ------------------------------------
>> 
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>> Yahoo Groups Links
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