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Buzzing from Roland Keyboard amp di's- SOS!

Discussion in 'Live Sound [BG]' started by lpbfender, Jun 18, 2017 at 7:43 PM.


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  1. Jun 18, 2017 at 7:43 PM #1
    lpbfender

    lpbfender

    Jan 7, 2012
    Stamford CT
    Never happened before but at last nights gig, my keyboardists Roland keyboard amps left and right out XLR di's added a major buzz to his amp when plugged into my Presonus RM 16 mixer. We were booth plugged into separate wall outlets with the Presonus tapping a Furman line conditioner.

    No real buzz in the PA but we couldn't direct him in.

    Any thoughts as to why?
     
  4. Jun 18, 2017 at 9:24 PM #2
    tshapiro

    tshapiro Supporting Member

    Aug 25, 2015
    Jax Florida
    My first thought would be grounding and I would throw in a direct box with a ground lift.
     
    4Mal, s0c9 and dheafey like this.
  8. Jun 19, 2017 at 6:23 AM #3
    dheafey

    dheafey

    Jul 22, 2012
    Massachusetts
    I think @tshapiro may have nailed it.

    I think some troubleshooting to narrow it down might help. Could be the room; could be something new with his amp.
     
  11. Jun 19, 2017 at 10:00 AM #4
    s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    Ft.Worth/Dallas
    1964 Audio artist, Fractal Audio Beta Tester
    Sounds like grounding issues.. could be that the keys amp was on a different circuit than the Presonus and they did NOT have a common ground.
     
    jeffbrown and 4Mal like this.
  14. Jun 19, 2017 at 10:15 AM #5
    Jebberz

    Jebberz Supporting Member

    Jul 3, 2012
    Quebec city
    I always carry ground lifted XLR patch cables on gigs for when this happens
     
  17. Jun 19, 2017 at 2:48 PM #6
    lpbfender

    lpbfender

    Jan 7, 2012
    Stamford CT
    Great ideas! The keyboardist unplugged the Roland and used the infamous grey three to two ac adapter ungrounded and it still buzzed.

    But I'll plug the setup again in my studio.
     
  20. Jun 19, 2017 at 4:08 PM #7
    kalle74

    kalle74

    Aug 27, 2004
    Separate outlets. Grounding problems, or differences in ground potential. Star-power everything, or add ground lifts (any worthy DI should have one).
     
  24. Jun 19, 2017 at 4:17 PM #8
    4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Try to avoid multiple circuits if you can...
     
    jeffbrown likes this.
  27. Jun 20, 2017 at 8:15 AM #9
    kalle74

    kalle74

    Aug 27, 2004
    Fixing it for you...

    Avoid multiple circuits. Period.

    In a worst case scenario, you could risk your life with mic zaps etc.
     
    s0c9 likes this.
  30. Jun 20, 2017 at 8:54 AM #10
    s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    Ft.Worth/Dallas
    1964 Audio artist, Fractal Audio Beta Tester
  33. Jun 20, 2017 at 8:26 PM #11
    lpbfender

    lpbfender

    Jan 7, 2012
    Stamford CT
    Great article. And thanks to all for the advice.

    The Roland amp DI's do not have a ground lift. I guess i could make an xlr cable as a go between that has the ground un soldered?
     
  36. Jun 20, 2017 at 8:29 PM #12
    lpbfender

    lpbfender

    Jan 7, 2012
    Stamford CT
    BTW I don't think I can run the PA and my bass setup plus the keyboard setup off the same circuit.

    Also what is "star power"?
     
  39. Jun 22, 2017 at 1:33 PM #13
    s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    Ft.Worth/Dallas
    1964 Audio artist, Fractal Audio Beta Tester
    basically, this..
    In ear monitors