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DI-out/ground lift

Discussion in 'Amps and Cabs [BG]' started by Berten, Feb 1, 2004.


  1. Berten

    Berten

    Jun 6, 2002
    Belgium
    I was just wondering: the manual of my amp says that I should use the groundlift to eliminate hum and noise. So when I use the DI, why don't I put that groundlift 'on' every time? And why do I have the possibility of lifting the ground or not? Why is there a ground if it can give hum??
     
  2. Finger Blister

    Finger Blister

    Jul 8, 2003
    Ground Loops cause Hum.

    A good system proper wired should not hum.

    In the event that a Ground Loop is present and is causing
    noise, then the Ground Lift should be used.

    Proper Procedure:

    Plug DI into XLR input.
    If no hum.
    Good to go.

    If there is hum,
    use ground lift switch.
     
  3. Berten

    Berten

    Jun 6, 2002
    Belgium
    But why not using the ground-lift allways???
     
  4. The ground is the electrical "earth" path for a signal. A signal MUST be grounded to work at all. Loops occur when a signal is going to ground in two different places and "looping" between them. When you "lift" one, you only give the signal one path to ground and eliminate the hum.
     
  5. Sundogue

    Sundogue

    Apr 26, 2001
    Wausau, WI
    You only use a ground lift if there is bad wiring somewhere, where the ground is interrupted and it actually causes the hum in the first place.

    If there is no interruption in the ground...you should not "lift" the ground as it is a safety concern, but sometimes the hum is too bad and that is your only option to remove the hum.