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Ground Loop question

Discussion in 'Amps and Cabs [BG]' started by Guiseppe, Jun 2, 2005.


  1. Guiseppe

    Guiseppe

    Oct 26, 2003
    Vancouver, WA
    I have an Ampeg SVPCL and SVP1600 in a 6u case, my ax is a Ken Smith Proto-J 5 (w/ preamp). I'll probably put on some 'rack isolation tabs' in the rack but was wondering about something else: I'm planning on putting in a power conditioner later in the month and if it would be a) safe and b) effective to put the 2-prong cheaters on my pre/power amp as they plug into the power conditioner, then let the AC from the power conditioner be the sole ground to the grid. If a ground loop occurs with 2 or more pieces of gear in the same rack, can I use the power condtioner for the ground and get rid of the loop?

    Thanks, guys!
     
  2. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Usually if all things are in one rack, on same rack rails, the grounds are close enough that there won't be a problem with induced hum.

    Even if there is some, you can re-arrange cables to get rid of it in every case I have run into.

    We do NOT think removing the ground pin, or defeating it by using a "ground lifter" is acceptable. Don't do that, the cord is the best and most reliable safety ground.

    The problem isn't the existence of "a ground loop" (only happens with aircraft), but with induction of currents into the grounds.
     
  3. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    If you get a loop within the short cable runs of a rack it's seldom if ever the fault of the power grounds. Even isolators are almost never required with properly designed gear. The only alteration you may need to use is signal cables with the shield disconnected at one end. With balanced connects even that is hardly ever required. For information on how to do it the right way go to www.rane.com and look at RaneNotes 151 and 110.
     
  4. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    SVP-CL has unbalanced main output......shield carries signal return, hence the problem CAN occur.