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MBF D.I. Trouble

Discussion in 'Amps and Cabs [BG]' started by jquinn86, Dec 17, 2013.

  1. Hey all. Just finished a sound check at a club and the DI on my mb fusion 500 was feeding a very loud hum/buzz to the board.

    Ground lift didn't change anything. Seems as though the xlr isn't clicking into position although it is pushed in fully, as far in as I can get it anyway.

    The connection gets used heavily over the last year or so, maybe 3 times a week. No problems over that time. I tested it at home yesterday and just fed the DI out into a powered speaker, didn't hear any unwanted noise, none. Had a similar issue at a show on the weekend but rather than troubleshoot I just grabbed a box and played.

    Is there certain xlr female ends anyone has found that don't fit properly? Could it be a busted solder? I won't be able to open it up until tomorrow but any advice would be appreciated.

  2. cableguy


    Jun 4, 2009
    North Bend, WA
    Phantom power maybe? Or if it was only at a certain club, maybe bad power if the ground lift didn't fix the hum. Only guessing though....
  3. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Is there a ground lift at the mixing board that you can try?

    A bad fitting connector shouldn't be an issue. The ground lift switch simply disconnects on of the three wires, the ground. Try jamming the switch on the amp a few times in case it is faulty. It could be that you have a bad cable running to the board. Try another one if you can.
  4. Pretty sure all was fine on the sound techs end of things, he seems to know his stuff. Cable is working fine with a DI box now.
  5. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    Wait till you start playing. That's when the gremlins rear their heads. :p

    Hope that it holds through the gig.
  6. georgestrings

    georgestrings Banned

    Nov 5, 2005
    IME, if your amp's DI has always worked well, and is acting as described in the OP, it's often a cable or channel issue outside of your amp - or a power issue...

    He could be the world's greatest soundman, and still have a channel on his snake go bad - it happens...

    - georgestrings
  7. Steve Dallman

    Steve Dallman Supporting Member

    A bad connection or broken wire on the pin 2 or 3 of the XLR feed, especially with phantom power, could cause this. I'd also suspect a bad cable or connector. Your amp isn't the problem. There are so many places a failure can take place. Cables and connectors don't last forever.