How can I shield inside an enclosure?

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OfficialCodini

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Apr 22, 2021
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What's the best way to shield my combo jacks (XLR / 1/4") inside a metal enclosure? I would like to shield them from EMI and RF, but most importantly, each other. Sometimes I can get signal to cross over from one jack to another when they are close to each other, and when the signal is particularly fairly hot. Is there an easy way around this or something I can do inside to isolate them and shield the jacks?
 
The answer is it depends - mostly on the physical configuration of adjacent jacks. Crosstalk such as you desicribe can be caused by poor PCB layout, improper grounding or capacative coupling. You need to mitigate all of these to eliminate or at least minimize it.

Cheers

Ian
 
The answer is it depends - mostly on the physical configuration of adjacent jacks. Crosstalk such as you desicribe can be caused by poor PCB layout, improper grounding or capacative coupling. You need to mitigate all of these to eliminate or at least minimize it.

Cheers

Ian
Thanks for the reply. As a reference, I've attached how it looks inside. Is there another way these should be grounded or something else that can improve this?
 

Attachments

  • IMG_7481.png
    IMG_7481.png
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What makes you think the crosstalk has anything to do with the jacks? If each cable is shielded and the shield is actually grounded properly, then crosstalk is almost certainly not a result of bad jack wiring. It might help if the enclosure itself was grounded which it does not appear to be. Otherwise, you should look at the other end and how each pair of signal conductors are referenced to 0V.
 
What makes you think the crosstalk has anything to do with the jacks? If each cable is shielded and the shield is actually grounded properly, then crosstalk is almost certainly not a result of bad jack wiring. It might help if the enclosure itself was grounded which it does not appear to be. Otherwise, you should look at the other end and how each pair of signal conductors are referenced to 0V.
Would grounding the enclosure just be connecting all of the chassis grounds to the box?
 
Thanks for the reply. As a reference, I've attached how it looks inside. Is there another way these should be grounded or something else that can improve this?
OK, first things first; pin 1 of each XLR and the sleeve of each jack needs to be connected directly to chassis at the connector and to nowhere else.

It would probably help if you read the attached document which tells what grounding and shielding is trying to achieve (but as others have pointed out, that may not be your problem).

The other question is what are the cables connected to at the other end and how far away is the other end?

Cheers

Ian
 

Attachments

  • grounding101v2.pdf
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pin 1 of each XLR and the sleeve of each jack needs to be connected directly to chassis

Connected directly meaning a good conductive path. That picture appears to show a powder coated chassis with no masking, so there are no conductive surfaces available without some grinding.
 
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