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Power Strip/Bar for Gigs

Discussion in 'Miscellaneous [BG]' started by eriky4003, Jun 20, 2012.

  1. During soundcheck of a gig on Saturday noticed my active bass was giving a buzz to my amp. I tried various checks to ensure it wasn't my effect causing the buzz so fairly certain it was the bass. Even ran an extension cord to the other side of the stage hoping it was grounding on my side. To reduce the buzz, I had to turn down the mid-high knob on the bass which cut back my enjoyment of the evening as the bass lost a lot of the highs.
    Don't have this problem at home or our rehearsal spot so I figured it was the electrical at the gig's location.
    Has anyone else had this problem? Were you able to resolve?
    Has anyone tried one of these to eliminate the problemhttp://catalog.bitsltd.us/catalog/SMART/LCG3.html
  2. Pilgrim

    Pilgrim Supporting Member

    Could be an RF field - could be a bad cable somewhere in the signal chain. After the fact, you really can't tell until you set up the system again. I'd say an AC problem is among the less likely causes.
  3. ggunn


    Aug 30, 2006
    Austin, TX
    Unfortunately (for audio, anyway), we live in a 60Hz AC world. It's all around us and there are any number of ways that 60Hz can pry its way into your signal. No matter what pathway(s) it has taken, it sounds the same. The only thing you can do is keep trying to eliminate likely paths and if you are lucky, you find enough of them that it drops down to an acceptable level. Guitarists that love the sound of single coils through high gain amps just have to grin and bear it.
  4. Stumbo

    Stumbo Wherever you go, there you are. Supporting Member Commercial User

    Feb 11, 2008
    the Intergalactic Mind Space
    Song Surgeon sofware
    You might also carry one of these with you.
  5. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Does your bass have single-coil pickups? Were there fluorescent lights at the gig?
  6. Munjibunga,
    No to either question. My bass is a Yamaha BB5GS and I saw there were previous posts indicating a similar issue with the active pickups, but no resolution.
    As indicated, I tried a bunch of combinations with cables but the two constants were my bass and my amp.
  7. For those who care:
    Purchased a Electro-Harmonix Hum Debugger which did the trick in our rehearsal room and my basement where I practice.
  8. kesslari

    kesslari Groovin' with the Big Dogs Supporting Member

    Dec 21, 2007
    Santa Cruz Mtns, California
    Lark in the Morning Instructional Videos; Audix Microphones
    I like the idea of a power stripbar.
  9. Roscoe East

    Roscoe East

    Aug 22, 2011
    ^^^Came in to make similar joke. :hyper:
  10. Odds are it was the powersupply for the neon signs. Nothing you can do about it except to turn them off. They throw out A LOT of RF and even humbucks can have hum with this.

    The Humdebugger works but thereis useually a cause if it. Bad cable, solder etc.

    "I don't want to die" tip of the day: NEVER, EVER use what is commonly called a "ground lifter". They say on them to NOT do this. The ground pin on the power cable is there to protect you.

    What I use is a Ebtech Hum Ex. This is a ground isolator. Overly priced but works great for power realted hum.
  11. boynamedsuse

    boynamedsuse Supporting Member

    Oct 13, 2010
  12. Hi.

    +1 for the RF field.

    And that kind of confirms it.

    Lights (or igniters in them more precisely), electric motors, frequency converters, you name it, all reflect noise back to the mains.
    Most will also create a field that can interfere with pickups.
    The field strenght decreases rapidly when moving away from the source though, so they're relatively easy to pinpoint (and to eliminate).

    If You can confirm that the interference indeed comes through the mains, you may be able to reduce it by using a line filter between your amp and the wall outlet. Most of the so called "power conditioner" manufacturers use that handy piece of device to lure in clueless customers for profit.

    If OTOH the bass is what picks up the interference as it seems to be, the Hum Debugger You bought may work. To an extent anyway.

    If an active instrument (whether it's the PU's, the pre-amp or both that are active) picks up hum though, there's usually something wrong with the circuit.
    IME anyway.

  13. mellowinman

    mellowinman Free Man

    Oct 19, 2011
    Solve Hum:

    1. Play continuously all night
    2. Have a noise gate just for your bass rig
    3. Make sure everyone in the bar talks loudly, all the time while you're gigging
    4. No neon lights, period
    5. Just ignore it, and pretend it's the sixties

    Those are some of the things I do, mostly number 5.
  14. ggunn


    Aug 30, 2006
    Austin, TX
    To eliminate as non-causes in your investigation or eliminate as a cause of the noise? In my case there is no eliminating the noise source, since it is a set of medium voltage transmission lines right outside my house.
  15. Damn florescent lights are the cause, more often than not. When I'm setting up for a gig, I often ask the manager if he can turn off as many lights as possible, especially those closest to the stage. Most club owners are pretty obliging.
  16. pflash4001


    Dec 2, 2011
    Make sure none of those fluorescent beer signs are plugged into the same circuit your powering the stage from. It'll be a cause of constant headaches.
  17. Johnny Crab

    Johnny Crab ACME,QSC,Fame/Hondo/Greco user & BOSE Abuser Gold Supporting Member

    Feb 11, 2004
    South Texas
    Had bad buzz(in the amp) about twice. The BSEE in me found:

    1) Large ballroom in a VERY expensive Houston hotel....cheap dimmers all over the room. My noisegate helped but I played a Brice T-bird($199 Korean) that night instead of the Gibson($1500).

    2) Club in Corpus Christi thinks it's cool to have a Texas-shaped NEON sign right behind the stage at their club. I nicknamed it "Mr. BUZZ". We had them turn it off for the duration of our show there.

    With single coil basses AND actives that have mids or highs boosted, you WILL encounter areas in rooms that have poor electrical planning and end up with spots with high RF fields. Turning left or right(at a 90 degree angle usually) and standing still lessens the buzz.....you are in a field. I've 2 basses that are virtually immune to such things: the cheapo Brice(go figure) and a Hondo/Fame that a previous owner shielded intenally with copper foil and installed Seymour Duncans.
  18. A friend of mine has one of these, and she swears it works, but neither of us can figure out how. Is it just a notch at 60 Hz (which wouldn't help with any source of hum "downstream" from the pedal, I would think), or is there some sort of magic going on?

  19. Hi.

    As a cause.

    If Your bass would be able to pick up the interference field of the transmission lines, you wouldn't be able to have any RF reception without the interference. Actually, no-one could.

    I also fail to imagine how AC transmission lines of any kind would be able to create any interference. At least no interference like were discussing here.

    The way I read the OP, the interference is somewhere betwen 200 and 2000 Hz.
    So, not the mains freq.

  20. Hi.

    I haven't looked into it, but I'd suspect either a Dolbylike signal processing, or the older way of flipping a part of the signal a few times.
    A bit like the good old humbucking pickup or microphone.

    So no magic.
    Most likely no fixed frequency either, that would be pointless (not to mention very difficult).