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    ground loop

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    kost

    Posts : 33
    Join date : 2009-05-12
    Age : 52
    Location : athens

    ground loop

    Post by kost on Thu Mar 10, 2011 1:16 pm

    "Hi to all

    Can you please explain what exactly is the ground loop?
    I am trying to eliminate the hum between foreplay 3 and VTA st70

    cheers"

    RMG

    Posts : 16
    Join date : 2010-06-13

    Re: ground loop

    Post by RMG on Sun Mar 13, 2011 9:19 am

    I believe it is when you have currents flowing from your amp to your preamp or vice versa through the grounding connections.
    When two or more devices are connected to a common ground through different paths, a ground loop occurs.

    j beede

    Posts : 316
    Join date : 2011-02-07
    Location : California

    Re: ground loop

    Post by j beede on Sun Mar 13, 2011 11:40 am

    "Ground loop" is often used as a generic description of a condition where local ground references within a system are at different potentials. In my experience they are easier to describe then to eliminate. A common case would be a piece of equipment grounded via its power cord and also grounded to another piece of equipment via the shield of an RCA cable. If the two ground references are at different potentials you have a loop.

    Pooch

    Posts : 53
    Join date : 2009-12-01
    Age : 66
    Location : Wa

    Re: ground loop

    Post by Pooch on Sun Mar 13, 2011 4:42 pm

    "A common case would be a piece of equipment grounded via its power cord and also grounded to another piece of equipment via the shield of an RCA cable".
    Is this to say a non grounded component could be effectively grounded through the shield to the other grounded component? IE non grounded Dynaco amp through RCA cable shield to grounded preamp.

    j beede

    Posts : 316
    Join date : 2011-02-07
    Location : California

    Re: ground loop

    Post by j beede on Sun Mar 13, 2011 9:18 pm

    Pooch wrote: "A common case would be a piece of equipment grounded via its power cord and also grounded to another piece of equipment via the shield of an RCA cable".
    Is this to say a non grounded component could be effectively grounded through the shield to the other grounded component? IE non grounded Dynaco amp through RCA cable shield to grounded preamp.

    The outer conductor of an RCA jack is often tied to the chassis of the component in which it is installed. The chassis often represents a local ground reference. Assuming two components are connected via a standard RCA cable where one component is grounded (e.g. via three prong mains plug) and the second component features a two prong mains plug, yes, the shield of the RCA cable can provide a ground path for the second component. NOTE: Some RCA cables are "directional" meaning the shield is grounded at the source end but floating at the destination end. In that case the second component would not have a path to ground through the RCA cable. Make sense?
    ...j

    mantha3

    Posts : 298
    Join date : 2010-11-10

    Re: ground loop

    Post by mantha3 on Mon Mar 14, 2011 12:27 pm

    This is a pretty good outline of how this is caused and fixed...

    http://www.lh-electric.4t.com/gnd_loop.htm

    howardnair

    Posts : 21
    Join date : 2010-05-31

    here is a article about ground loop

    Post by howardnair on Fri Mar 18, 2011 8:22 pm

    http://mikeriversaudio.files.wordpress.com/2010/10/grounds_and_shields_revised1.pdf

    tubes4hifi
    Admin

    Posts : 1261
    Join date : 2008-11-30

    Re: ground loop

    Post by tubes4hifi on Sat Mar 19, 2011 7:39 pm

    great links, here is another one: http://www.equitech.com/articles/enigma.html

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