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earth hum

Discussion in 'AV Pre-Amp/Processors & Power Amps' started by ajwoodhouse, Jan 23, 2005.

  1. ajwoodhouse

    ajwoodhouse
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    Hi,

    I have the front L/R preouts of my Rotel AV processor connected to my Naim preamp's AV input (in addition to loads of other cables obviously!).

    The hifi kit (incl. DVD player) is plugged into one mains wall socket and the TV and VCR are into an adjacent mains socket.

    With AV selected (with TV on or off) I get what sounds like earth hum from front speakers - when no devices are connected to the TV it disappears. It doesn't happen when using my projector which is plugged into a different socket on the other side of the room. This is connected to my DVD player via component cables.

    This leads me to believe I need to ensure the TV has the same earth as the hifi kit. Is there a simple fix? Can I connect the two wall socket earths together?

    Due to physical restrictions (TV has short mains cable and is some way for the hifi) I can't simply use the same mains block from the TV. And I'm wary of daisy chaining mains blocks as I think the load may blow the 13A fuse.

    Any ideas or suggestions welcome?
     
  2. Mylo

    Mylo
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    I've moved your thread here as you may find the answers you require.


    Mylo :)
     
  3. eviljohn2

    eviljohn2
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    You could try loosening a case screw on the TV and attaching a bit of wire to create a flying lead. Next, see if you can cure the hum by touching the lead to the casework of your other equipment. If you do, just connect this flying lead to the relevant equipment in the same manner and off you go. :thumbsup:

    Otherwise, you could consider removing/adding an earth connection somewhere else in the chain but this requires some knowledge and care. Try my earlier suggestion and if that doesn't work I'll clue you in some more. Hopefully someone else might have some ideas too. :)
     
  4. olliemac

    olliemac
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    do you have an aerial feed to the tv via other equipment. try uplugging each and every cable one by one and listen if it disappears. this will narrow it down. you have a loop somewhere .
     
  5. ajwoodhouse

    ajwoodhouse
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    I have resolved the problem now :rotfl:

    got recommended one of these on the Naim forum:

    Xitel Ground Loop Isolator

    [​IMG]
     
  6. Reiner

    Reiner
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    You can get those at car audio accessory shops, too. It's usually just a box with a 1:1 audio-transformer, electrically isolating in- and outputs.
     

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