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  • Grounding issues

    So what is correct, or most common - useful?

    After running into problems with fantom power,  I started going thru all my cords and snakes to see what might be up.  Found that about half my factory XLR cords had pin 1 connected to shell and half did not ???

    Furthermore, my (very) old Whirlwind snake has all shields (pin 1) common and tied to shells and box.

    That said, I have not had a lot of ground problems.  Also all my sends from the mixer are pin 1 lifted.


  • #2
    According to AES standards, pin 1 should not be connected to the shell. As you've found it sometimes causes problems with phantom power.

    There is some controversy on the subject because while is it generally a benefit to not connect pin1 to the shell at audio frequencies the opposite is the case when you get up into radio frequencies.
    Don Boomer

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    • agedhorse
      agedhorse commented
      Editing a comment

      Almost universally, pin 1 should not be tied to the shell. Most (sending) devices are configured with no shell connection to ground as the ground (effective ground) is provided by the AC mains system and does not need to connect between pieces via the shell which can not be lifted (via a ground lift on pin 1) once configured as tied to shell.


  • #3

    Thank you gentelmen, for replys.  So what do you think is up with some manufactures making XLR (mic) cords with pin 1 tied to shell and some not ?   I have a few newer batches of cords that came from different vendors - and both schemes are used.  Is it oversight or disagreement?

    As for my old snake - I'm guessing that having all pin 1s tied together is not ideal ? 

    I can easily change the connections so shells are isolated but not easily undo the common pin 1s - they are peeled back pretty far and twisted together. 

    I'd have to chop off the box and try a complete rewire - hoping that mylar metalized  film sheathing around each conductor pair has not lost integrity in the snake cable itself.

    Comment


    • agedhorse
      agedhorse commented
      Editing a comment

      It's because of a lack of understanding by the lowest tier manufacturers. ALL of the professional tier cable manufacturers do NOT connect pin 1 to shell.

      With regard to common pin 1 in the snake stage box, that's not a big deal since they are also bussed to a common ground but at the mixer end (star ground point).

      With regard to pin 1 tied to shell, what is somewhat common is the shell of channel 1 being tied to pin 1 to carry the shield around the entire box. In fact, even t his is being dropped due to the possibility of ground loops if the box touches a metal stage.













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