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Can you get rid of single coil hum

Discussion in 'Pickups & Electronics [BG]' started by funkybass, Jan 23, 2014.

  1. funkybass


    Oct 19, 2006
    We got a new sound system at church and now I'm going direct. Since I'm loud in the mix now, you can really hear the hum if I'm not touching the strings or if I turn the volume down at all. The sound man thinks it's a grounding issue, but every single coil bass I've had has done this. Is there any way to get rid of the hum with out changing pups? The bass is a Carvin sb5000.
  2. There is no way to get rid of it, except to run your pickups at equal volume, if there are pairs of RWRP coils.
  3. Make sure you controll cavity is sheilded AND grounded, then buy a noise gate pedal or the Electro Harmonix Hum Debugger.
  4. Jerry Ziarko

    Jerry Ziarko Supporting Member

    Feb 23, 2003
    Rochester, NY
    Touching the strings should have zero effect on single coil hum. This sounds much more like a ground problem of some sort. Before messing with your bass THOROUGHLY check every cable, or device in the signal path.
  5. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism Supporting Member

    If you have hum that goes away when you touch metal/strings/bridge you have a shielding issue. If you touch metal and the noise gets louder you have a grounding issue.

    You cannot completely remove it but you can reduce to a level that makes it negligible, considering the amp is probably getting some noise from the AC anyways.
  6. OnederTone

    OnederTone Aguilar Everywhere Gold Supporting Member

    Aug 15, 2002
    Thornton, CO

    That is not correct. If the buzz goes away when you touch the strings or metal, there is a grounding problem. Trace all the ground wires and make sure they are correctly soldered and go to a common ground.

    If the buzz starts when you touch something metal, it's still a grounding problem, but everything is jacked up, take it to a professional.

    Typical 60 cycle/single coil hum gets louder/quieter depending on directionality. Copper foil or shielding paint helps, but it never goes away unless you have your pickups at equal volume, but that's the character of single coils, if you don't like that, don't play them.
  7. f.c.geil


    May 12, 2011
    This. The other clue, for me, was that the hum was there with the volume turned down. Single coil hum varies directly with the volume knob.
  8. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars

    Actually he was absolutely correct, it would be a shielding problem and not a ground problem.
  9. CrashClint

    CrashClint I Play Bass therefore I Am Gold Supporting Member

    Nov 15, 2005
    Wake Forest, NC
    DR Strings Dealer
    Can't say I have ever heard a dead quiet Single Coil pickup and if your church has stage lighting or lots of fluorescent it can play havoc sometimes. Shielding paint does a descent job of shielding but I have found in my experience copper tape works best. When I had my old 74 jazz bass back in high school, the school had the crappiest electricity. Most of the electrical sockets were ungrounded two prong. Anytime they turned on the Spot Light (probably built in the 40s) the J basses and Strats would sing.

    I shielded the pickup cavities, control cavity and the back side of the pick guard then connected all the shielding with a wire that came back to ground. I also had my pickups dipped in wax to cut down microphonics which made a huge difference but I still on occasion had some hum.

    I know the Fralin pickups are designed to reduce hum when the volume is turned all the way up.
  10. bassdude51

    bassdude51 Supporting Member

    Nov 1, 2008
    Central Ohio
    Single coil hum is directional. Some times turning to the left or right will greatly reduce the hum and almost stopping it.

    But, if there are things near by like florescent lights, electronics etc there will be hum and nothing to be done about it.
  11. Phalex

    Phalex Semper Gumby Supporting Member

    Oct 3, 2006
    G.R. MI
    I feel your pain! At church they like to stick a couple of flood lamps on dimmers right in front of me. Keep your hands on teh strings when you aren't playing.
  12. uOpt


    Jul 21, 2008
    Boston, MA, USA
    The single coils pick up both oscillating electric fields and they pick up huge amounts of magnetic oscillating fields. You can easily shield against the former (and hence quieten up guitars that pick noise up in the electronics) but there is no practical way in an electric guitar or bass to shield against the latter. Hum-canceling is the only thing that really helps.

    Having said that, making sure you kill all the electric field interference you can will often make the overall amount of noise acceptable even with single coils. And you can try to go after the magnetic noise source such as neon light, fridges and the like.
  13. BlueTalon

    BlueTalon Happy Cynic

    Mar 20, 2011
    Spokane, Washington
    Endorsing Artist: Turnstyle Switch
    Other people have mentioned shielding and grounding, which should be done anyway IMO. But I can't quite get past your premise -- to me, it's like asking if there's any way of making your foot feel better without taking the rock out of your shoe.

    Why on earth do you want to keep the pickups that are causing you consistent problems? That Carvin pickup is a standard J shape, right? There are just too many options for good sounding silent hum-cancelling J pickups to put up with persistent unwanted noise.
  14. f.c.geil


    May 12, 2011
    That's kind of a snarky answer, don't you think? Not altogether on point, either. OP didn't ask if he could buy a different bass or different pups. He asked how to work with what he's got. Besides, "good sounding" just isn't good enough for many people, and hum-cancelling pickups don't sound the same as single coil pups. Not everyone can afford to buy a bass, then put after market pups in it. Lots of us don't want to and/or can't modify our basses, too. There are many reasons to leave your bass alone, but want to eliminate a problematic sound.
  15. uOpt


    Jul 21, 2008
    Boston, MA, USA
    Why do you need to take your hands off the strings, anyway?

    If you have to, use an antistatic wristband and ground it.
  16. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism Supporting Member

    Seriously? I like to entertain my crowd, so sometimes I clap.

    A bass should be dead silent until you tell it to make noise, 60hz hum is a serious issue and should be treated as one. I personally would not take a bass on stage or near a studio if it hummed, as far as I am concerned a humming bass is broken. And do not toss the electronics due to hum, talk about amputating for a paper cut.

    Please listen to my advice, funkybek is incorrect in his assessment, I do not know electronics but I know 60 cycle hum quite well, your bass has a shielding issue. A grounding issue gets louder when you touch metal.
  17. bassbenj


    Aug 11, 2009
    Well I do know electronics and here's the true scooby. If hum goes away when you touch ground it is a shielding OR a grounding problems.

    A shielding problem is simple. The bass has NO conductive box around all the wiring and pickups and the wiring is picking up hum from your body acting like an antenna. When you touch ground you short out yourself as an antenna and the hum goes away or becomes less. Fix is to install copper foil or conductive paint around all wires, controls and pickups. Note that this can never be totally perfect (watertight conductive box) because tops of pickups have to stick out.

    A grounding problem can be many, but assume that all that happens is that the ground connection to your shielding came loose. In this case touching ground (bass jack body) will make hum reduced. BUT touching the now free-floating shield will inject hum from your body-antenna into the shield where it will be injected into the circuits and hum will get LOUDER. Of course if you touch something grounded, hum is less so it all depends on WHAT you touch! I repeat. Shield MUST be grounded or it not only won't work to block hum, but actually can inject more in! Suppose, for example, what happened was your ground to the jack broke off but the strings (bridge) are still connected to the "floating" shield. Now touching the strings will make hum louder as they are no longer grounded and are injecting hum right into circuits.

    Finally to answer all the single coil comments, let me say that the reason one uses and loves single coil is because of the clarity of tone which comes from sensing strings in only a single location. And as noted with single coil hum touching ANYTHING will make NO difference in hum level! But moving your bass around will. Distance from magnetic hum source (in my case the power transformer in my amp!) will reduce it and by swinging bass direction around, often you can find a "null" orientation (sometimes not playable) where hum is nearly gone.

    Now HERE is the key to single coil love. If you FIRST totally shield your bass so there is ZERO electric (goes away when touch the strings) hum, you'll find that the single coil hum that remains will seem MUCH less objectionable to your ears.

    Only solution beyond that is "noiseless" dual coil pickups. Now these DO only sense the strings at one spot giving "sort of" a single coil tone, but because there are two coils, the inductance etc. doesn't match a true single coil pickup so the "noiseless" tone just never quite nails the true single coil tone. Some however, (such as Nordys or my SCN jazz pickups) are quite nice.

    The only true solution to single coil hum is to use a dummy coil which picks up hum but not strings. And that has to be mixed in electronically or the added inductance again alters the tone. As far as I know only certain Alembic basses are built this way.

  18. Stumbo

    Stumbo Wherever you go, there you are. Commercial User

    Feb 11, 2008
    Intergalactic Mind Space
    Song Surgeon sofware rep.
    what's your setup for going direct?
    Tried different cables?
  19. BlueTalon

    BlueTalon Happy Cynic

    Mar 20, 2011
    Spokane, Washington
    Endorsing Artist: Turnstyle Switch
    It wasn't intended to be snarky. I have the same philosophy as DiabolusInMusic, who said "A bass should be dead silent until you tell it to make noise, 60hz hum [or any extra noise] is a serious issue and should be treated as one." The OP has had the same consistent problem with every bass with single coil pickups on it he has played. That means he has had the same experience across multiple basses.

    He obviously doesn't like the noise, but he continues to use single coil pickups and doesn't want to change. I think it is entirely on point to question his position and the reasons behind it as part of the overall assessment of his situation. (If he can afford multiple basses, it's not a stretch to think he might also be able to afford -- or save for -- a set of pickups.) But I admittedly come from the school of thought that excellent pickup tone + noise = crappy pickup tone.

    My guitar playing best friend does not share that worldview with me, and apparently many here at TB don't share it either. That doesn't make it not a legitimate point of view, regardless of how snarky it may seem to those who don't share it.
  20. BlueTalon

    BlueTalon Happy Cynic

    Mar 20, 2011
    Spokane, Washington
    Endorsing Artist: Turnstyle Switch
    I agree with all of what you said. I am pretty meticulous about shielding and grounding.

    I disagree about dual in-line coils not nailing the true single coil tone, but for the sake of the discussion let's say that you're right -- an in-line dual-coil pickup can get very close to the tone of a single coil, but not match it exactly. It becomes a question of degree.

    Conversely, when you flip the argument around, it also becomes a question of degree. An excellent job of grounding and shielding will make the hum and noise from single coils "MUCH less objectionable", but will not eliminate it.

    If you want the perfect tone of a single coil pickup and no noise whatsoever, it is theoretically possible to get -- but not in the OP's environment. Since his current situation is unacceptable to him, the next question becomes: What sort of compromise is he willing to accept?

    His choices, as presented in this thread, are to keep the single coil pickups & tone and to try to minimise the noise, or to eliminate the noise altogether and perhaps have a little different tone. Either one represents a trade-off.

    Speaking for myself, as one who hates noise of any kind, the choice for me was easy. I use Fender Super 55 pickups in my bass (the one in my avatar), and the sound is so good that I will never go back to single coils in any of my basses. In my experience, to my ears, I lose absolutely nothing in the tone by using in-line dual coils instead of single coils.

    Some people say they can tell the difference in tone between a single coil pickup and an in-line dual-coil pickup. I don't think they can. It might be true, but the only way I think they could tell for sure is the existence of unwanted noise in the single coil.