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Using the DI on my head. I have an Ashdown ABM 500 Evo III

Discussion in 'Amps and Cabs [BG]' started by creis2, Jul 26, 2013.

  1. creis2


    Nov 11, 2011
    Cambridge, MA
    I played a gig the other night, and the sound guy told me to use another DI box because the DI on my head doesn't have a ground lift. I told him I don't own one, he got all agitated, and pulled one out of his milkcrate.

    I didn't know what that meant, so I did what he said.

    I looked at other heads, many have a ground lift button, I asked myself why doesn't mine?

    The manual says this:

    ""The output signal from this XLR socket is set to a level and impedance suitable for connecting directly into the Microphone input of a mixing desk for either Direct Injection into the PA system or for recording. This must ONLY be used into a
    Balanced Microphone input. It is not intended for any other type of connection. This has a floating ground
    that is referenced to the mixing console it is plugged into and should not need ground lifting. It is also
    unaffected by Phantom Powering on the Microphone input. Make sure your XLR plug does not have the
    shell of the plug internally connected to the ground signal or this will connect the system to the chassis
    ground of the amplifier and may cause problems with hum."

    Can someone help put this into layman's terms?
  2. 1) Your amp has a permanent ground lift.
    2) If the mike cable used is wired to make the connector's shell grounded (some do some don't) you can have grounding problems (hum).

    Sounds like the venue's cable had a grounded shell on the cable which caused a ground loop.
    3) The sound man was having a bad night or was just a jerk.
  3. creis2


    Nov 11, 2011
    Cambridge, MA
    I really have never had a problem with it before, but most gigs I play with this rig aren't miced.

    So again in laymen's terms, should I just ignore the guy's request and not worry about a ground lift?

    I found these , but with my head, is it necessary?

  4. You could pick up that ground lift cable, but you won't know if the shells are grounded until you get/use it.
    If the mike cable does not have a grounded shell going to your amp then you have no need.

    It is a strange way for them to do their DI.
  5. creis2


    Nov 11, 2011
    Cambridge, MA
    Yeah, this is all another language to me.

    Is it just a good idea to put this situation behind me, and just leave everything as it is? I don't mind spending 10 bucks on a ground lift adapter if it might come in handy, but if I don't need it, I don't want it.
  6. It might come in handy for the occasion that the venue's cable is wired with the shells grounded. Up to you whether to worry about it or just make them deal.
  7. AshdownMad


    Apr 19, 2011
    Suffolk, UK
    I thought Sound techs shouldnt use shell grounded cables for DI on amps anyway?

    Never had this on stage (Maybe its different over here?)... Or at least never noticed it
  8. I have this same problem with my Ashdown EVO 900 III - buzzing through the PA when the DI is used - sometimes just a faint hum, sometimes it is a very loud buzz.

    I had this exact problem with my old Warwick Profet amp last year and had both the amp and my Ibanez TR Expressionist active bass looked at and neither were found to have any problems that would contribute to excessive PA buzzing – the guy who looked at my amp said a simple external DI would fix the problem.

    I’ve had the Ashdown amp 6 months now and this problem only flared up again about 3 months ago.

    I'm pretty sure it is a power problem because at one gig a few weeks ago my bass amp wasn't even turned on and there was buzzing through the PA when DI was plugged into the desk..

    I don’t really want to pay $$$ and get the amp looked at only to be told there’s no problems there.

    Might e-mail the guys at Ashdown and see if they can offer any advice?

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