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Direct out noise

Discussion in 'Amps and Cabs [BG]' started by jimbass55, Jan 8, 2005.


  1. I have an Eden Metro which I love, but when I run direct (from back of amp) to the board for larger gigs, I get alot of buzzing noise. I run a box in between my bas and the amp, but then my sound is at the mercy of the mix.

    What is wrong with my amp? I also notice noise at my house even at low volumes, and it stops when I touch the strings. (Ground) This doesn't happen when playing live. The only issues are when I go direct.

    Help.
     
  2. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Hi jimbass55, there's probably nothing wrong with your amp. The buzzing you're experiencing is pretty typical in situations like this, it's the result of something called a "ground loop", which means that ground potential on the board is not the same as ground potential on your amp. Typically this problem gets a lot worse with long cables, or when the two pieces of gear are plugged into different outlets (eg on opposite sides of the room or something).

    What you want to do is put a transformer coupled DI between your line out and the board. This will isolate the grounds from each other, and it should result in significant mitigation of the ground loop problem. But make sure it's a passive "transformer coupled" DI, and not an active DI that uses op-amps to drive the output. The transformer is what you need, that'll isolate the grounds. For lots of information on this and related grounding topics, see the Jensen Transformers web site, in the "white papers" and "schematics" sections.

    http://www.jensen-transformers.com
     
  3. Sorry for not responding sooner. I didn't notice anyone had replied. I have a Behringer Ultra DI, would this work? I know I can use it in the chaing before the amp, but I am wondering if I can use 2 mic cables off the back of my amp. Thanks again.