MBF D.I. Trouble

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


  1. jquinn86

    jquinn86

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    Location:
    Edmonton, Alberta Canada
    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.

    Thanks
     
  2. cableguy

    cableguy Supporting Member

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    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

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    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. jquinn86

    jquinn86

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    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.
     
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  6. beans-on-toast

    beans-on-toast Supporting Member

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

    Hope that it holds through the gig.
     
  7. georgestrings

    georgestrings Banned

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    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
     
  8. Steve Dallman

    Steve Dallman Supporting Member

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    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.
     

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