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Would a DI box be the solution I'm looking for

Discussion in 'Effects [BG]' started by LiquidMidnight, Mar 7, 2006.

  1. LiquidMidnight


    Dec 25, 2000
    Here's the problem: When I play at this one club, I have to deal with a crazy amount of line noise from the electrical wiring in the place. It's so bad that at a medium volume, the signal lights come on my power amp even if I'm not playing anything. This of course goes through my preamp's DI, and out through the FOH mix, so I have to spend 20 minutes during sound-check trying to eliminate as much of this noise as possible. Even if I plug into our soundman's power supply, it's still there. I've tried plugging into different outlets, still there. I only get this hum at this club. Our soundman has a DI box, but it runs on phantom power, so there's still hum.

    I was wondering if a good simple passive DI (with no phantom power) would be a good solution for elimitating the hum in the FOH mix. Obviously, I would still get hum through my rig, and I couldn't play too loudly on stage, but at least the mix that counts would be clean. Also, do you recommend any good DI boxes? I know the Country Man is the standard, but I've been looking at the Radial Pro.

    Thank you.
  2. tommy.genes


    Feb 16, 2006
    Yo! Philly
    I'll come out of lurk mode to give you a definite maybe.

    Some questions:

    Does your amp hum even when nothing is connected to the DI? The fact that plugging into the soundman's supply didn't fix the problem may already answer this question.

    Does your amp hum when your bass is not plugged in or when the volume on the bass is turned all the way down? This may deterimine if the noise is being introduced through your pickups. If it is, your plan will not fix the problem because tapping the signal right off the bass will still include noise.

    If the problem is that your amp just picks up noise in that particular room for some reason, picking the signal right off the bass before the amp should work. I'm just not sure why your soundguy's phantom-powered DI didn't fix the problem. Did you try the ground-lift switch? Does his active DI have an option to run off batteries i/s/o phantom power?

    If neither of those last two points help, I would suggest borrowing a passive DI to try before you plunk down money on one. I'm not fully convinced that it will fix your problem.

    BTW, the Radial is passive, but the Countryman is active, with the option of running off either batteries or phantom power.

    -- T. G. --
  3. SteveC

    SteveC Moderator Staff Member

    Nov 12, 2004
    North Dakota
    I'm fairly certain in a situation like that the only solution is "clean" power. That is, a line that is separate from the rest of the bar - especially neon lights.

    We play in a place that has a million bar lights. Th eentire PA buzzes. There's not much you can do. You may want to try and find a conditioner of some kind that you plug into th eoutlet and then plug your gear into that. It may help depending on how bad it is.

    If bars/clubs/restaurants are going to have live music, they should take the time and MINIMAL expense and run a separate 20 amp circuit.
  4. Tedintheshed

    Tedintheshed Banned

    Oct 8, 2004
    Columbus, Ohio
    I have just one question to start with: do the other musicians you play with, especially guitarists, have this problem?
  5. LiquidMidnight


    Dec 25, 2000
    Thank you for all of the responses.

    Now to answer the questions. :D

    Our guitarist doesn't seem to experience this problem. It could be due to the lighting. Our light tech runs a lot of lights at this venue, but I've tried plugging into outlets that weren't on the same line as his lights, and I still get the hum. It doesn't seem to buzz until I turn off the mute on my tuner and turn up my bass' volume pot. Still, I've plugged two different basses in (active and passive) and still seem to get a serious amount of hum. Obviously, the passive wasn't quite as noisy, but it was still pretty noisy. I'm taking in a Carvin bass that I didn't have the last time I played here, so I'm curious to see how it fairs, since the Carvin has a very quiet preamp. I do have a furman conditioner that did alleviate a lot of line noise in clubs, but it doesn't eliminate the noise here. I've tried both the ground lift on my preamp, and the various groundlifts and pads on the DI box. The problem does seem to be with power, because I've run off other soundmen's power supplies in this club with no noise problems. But I've also run off our main sound guy's power supplies in other clubs, but I don't get hum anywhere else.
  6. Tedintheshed

    Tedintheshed Banned

    Oct 8, 2004
    Columbus, Ohio
    Do you always plug in to the same outlet, or when you plug into a different outlet is that outlet on the same circuit as the others? There may be a bad circuit involved.

    That possibilty aside, this is usally caused when a non-sheilded cable, such as a speaker cable, crosses a power cable. It may not be what you are running, but how it is being ran.

  7. uly_


    Jul 4, 2005
    Also remember NOT to play with your cellphone in your pocket.

    I've managed to get some really wicked synth-alike sounds at rehearsals because of my cellphone being in my pocket :D
  8. tommy.genes


    Feb 16, 2006
    Yo! Philly
    So it sounds like at least some of the noise is coming right from the bass. That's not necessarily the bass' fault. If the power in this place is as bollocks as it sounds to be, it could be radiating noise all over the place.

    Like I said before, though, try to borrow a passive DI before spending money on one. It may not totally fix your problem.

    IIRC, Carvin basses come standard with shielded control cavities, so that might actually make a difference. There's still the pickups though. That's kinda what they were designed to do, "pick up".

    -- T. G. --
  9. MrBEAR

    MrBEAR In Memoriam

    "It doesn't seem to buzz until I turn off the mute on my tuner and turn up my bass' volume pot." Liquid Midnight.

    Have you tried taking the tuner out of the equation?
    I have an old Korg, size of a cassette tape, that is unusuable in the signal chain for the exact reason you describe. It is not "True Bypass" and affects the sound tremendously.

    Just a thought.
  10. LiquidMidnight


    Dec 25, 2000
    Yes I've run my bass directly into the preamp, and still experienced the noise. Like I've said, I'm 99.9% sure it's some sort of power problem.

    I still love how quiet the Carvin is, though. The bass I was using prior had a somewhat noisy preamp, but it wasn't that noisy! Like I said, I could light up my signal indicators on the power amp without playing anything at this place. I don't think you can even gate it.
  11. basseuphoria


    May 19, 2005
    have you tried a Power Conditioner. it regulates the voltage and the frequency (120v@ 50-60 Hz) and really cleans it up. if you have some buddies that work w/ computers, they can probably help you w/ this.:)
  12. Power conditioning up the whazzo ain't gonna help you any with this problem. The issue here would seem to be EMI, electromagnetic interference. If you can get rid of all the hum and buzz (or most of it) by simply turning down your bass, then the source of the noise is EMI being picked up by your pickups.

    The only sure fire solution is to place the entire band, PA and engineers desk included, inside a faraday cage whilst the lighting gear and everything else is outside the cage. Small problem, Faraday cages that big are rare and expensive... plus your buddy in the audience has trouble handing you beers inbetween songs!

    Start with good quality, well sheilded cables and clean ground connections throughout. Move your entire rig to another part of the stage or change it's orientation. (Ever noticed that hum changes as you turn through 90 degrees on stage?) Think about upgrading the sheilding on your bass or using a bass with a humbucker.

    Move the lighting dimmers as far away as possible from any of the audio gear or cables. Keep all audio cables away from power cables, and if they must cross, run them at right angles to each other and NEVER run an audio cable parallel to a power cable.

    In the meantime, use the shortest leads possible, don't leave them coiled when in use and put a DI at the earliest possible part of your signal chain to reduce the amount of interference being picked up.
  13. Jerry Ziarko

    Jerry Ziarko Supporting Member

    Feb 23, 2003
    Rochester, NY
    I think niftydog has pretty much nailed it! This indeed sounds like EMI. I would also add in this situation, there will be little or no difference between a passive or active DI.

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