Doepfer

No, you should not. But you have to reassure, that the ground connection 
is provided by the 3.5mm cables between the R2M control box and the 
A-100. Do NOT(!) use 3.5mm cables with stereo sockets!!!


On 28.06.18 18:58 , Diego Ragnini diegora@free.fr [Doepfer_a100] wrote:
> Hello,
> regarding the floating GND matter, has the Ribbon R2M control box a floating ground as well? In other terms, do I have to connect the black box metal frame to the ground/earth?
>
> Best, Diego
>
>> Il giorno 20 giu 2018, alle ore 09:58, yahoo@doepfer.de [Doepfer_a100]<Doepfer_a100@yahoogroups.com>  ha scritto:
>>
>> Yes, these are the correct terminals. If the GND connection really solves
>> the problems one has to think about a permanent solution. But I have never
>> heard about similar problems from other customers. And we use A-100P9
>> together with A-100LC3 during exhibitions or work shops and never had any
>> problems.
>>
>> Best wishes
>> Dieter 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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>>> ------------------------------------
>>> Posted by: Diego Ragnini<diegora@free.fr>
>>> ------------------------------------
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>>
>>
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>
>
> ------------------------------------
> Posted by: Diego Ragnini<diegora@free.fr>
> ------------------------------------
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