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DI Box?

Discussion in 'Live Sound [BG]' started by NZBassman, Oct 22, 2013.

  1. I have an Ashdown EVO 900 III and a Warwick 4x10 cab & I play an Ibanez TR Expressionist 4 string active
    We mic the instruments through the PA at gigs and I use the DI on my amp to go to the desk for FOH sound.
    Most of the time it’s fine and there’s no problems, but sometimes when we DI the amp it buzzes through the PA… I’m pretty sure it’s a power problem with the power source at some venues – I always plug into the same power source as the PA and it only happens about 1 in 3 or 4 gigs
    The other day my amp wasn’t even turned on and the bass channel on the PA was buzzing. (lead was connected from amp to PA though)
    We’ve tried different leads, different channels in the PA – but at some gigs it just buzzes and I end up using a cheap old mic and mic the cabinet up.

    If I use a DI box it should eliminate this problem should it not?
    If so what sort of DI box should I get – active or passive?

    I'm new to the DI Box thing so any advice would be great
  2. Kael


    Dec 26, 2004
    Oklahoma City
    99% of the time this is a grounding issue. If your head has a ground lift, flip it when you encounter this buzz. If it doesn't, get a DI box with a ground lift. Virtually every DI box has one, so even a cheapo will work.
  3. yeah - I'm pretty sure my amp has a ground lift function and it is always switched on
  4. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    Try to borrow one with a ground lift and see if that fixes the problem. Then you'll know if that IS the problem.
  5. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    Try turning it off.
  6. Whatever you do, DO NOT just go ahead and buy a Radial JDI, because that would cheat you out of years of dinking around (thereby gaining character) whilst learning simplicity the hard/slow way.
  7. Is that you Calvin's dad?

  8. thanks for the suggestions - I'll have a look at my amp for the ground lift switch.
    I don't want to race out and buy a DI Box unless I really have to!
  9. Not that I know about, anyway...

  10. john m

    john m Supporting Member

    Jan 15, 2006
    Even if the amp is OFF, the ground is still connected.

    Get a DI with a ground lift or make a ground lift XLR m to XLR f. Clip the shield at the amp end. Mark the cord and keep it in your bag of tricks.
    dheafey and ialma like this.
  11. BassCliff


    May 17, 2012
    So. Cal.

    If your amp does not have a ground lift, these also work well as a ground lift, when necessary. And they're cheap.


    If you use one of these on your amp, make sure you don't get shocked by your microphone. :eek:

    Thank you for your indulgence,

  12. thanks for that - we always use XLR leads, but how do you clip the shield? - I've never heard that before.
  13. what on earth (no pun intended) are they? and where on your amp would they go?
  14. BassCliff


    May 17, 2012
    So. Cal.

    That's a 3-prong AC adapter. You use them on your electrical cord before you plug them into the wall. It lifts the ground. This is what the electrical cables look like in the US.


    I see you're in New Zealand. I imagine yours would look a bit different if you use the EU-type 50Hz system.

    Something like this? I really don't know.


    Thank you for your indulgence,

  15. Grounding is a good thing, use the ground on. The ground lift should only be used if there is a buzz.

    I'm leery of those adapters. It is the same old non-sense of clipping off the grounding plug. Replace those obsolete power outlets instead. The ground pin and grounding is there for many safety reasons.

    The OP seems to have the problem because he "lifted the ground" on his amp, when he should not have done so at that venue. The buzz was there. Perhaps, if he keeps the ground on the buzz will go away? Try that and let us know how it goes. It costs you nothing.

    Sometimes, lighting causes problems with the amps on stage. In that case, an external DI hooked to the Mixer board is a great solution.
  16. Removing AC ground from an amp is about the dumbest practice there is. One little fault and the amp chassis becomes 240v live and YOU become ground.
  17. BassCliff


    May 17, 2012
    So. Cal.

    It's not an ideal solution. And I have had to put up with a certain amount of buzz in some situations where I didn't want to lift the ground on my amp. Caution is always advised. But I have done it many times and I'm still here to tell you about it. I'm just offering options. We have to carry only 120v here in the States. ;)

    Thank you for your indulgence,

  18. tbirdsp


    Sep 18, 2012
    Omaha, NE
  19. BassCliff


    May 17, 2012
    So. Cal.


    Thank you for your indulgence,

  20. thanks for all your suggestions.
    As I mentioned is only happens at some venues and last Saturday when it happened, we unplugged the bass amp and put it in another power outlet and it seemed to work fine (no buzz). So it must be an earth / power problem?
    looking at my amp last night I don't think there is a ground lift switch - which is weird for a fairly high spec amp!

    A couple of people have suggested I get a 'Sans amp' DI / Pre Amp because they are so good and people who have them rave about them. but they are $300+ here in NZ, whereas I can buy a standard DI Box for about $70.

    The only problem with a DI Box is it bypasses the EQ on my amp - currently when I DI from the amp to the desk I can choose Pre / Post EQ and when I have the EQ on (post?) the signal to the desk is a lot stronger and fuller, whereas with it off we have to turn up the gain / volume on the desk.

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