Hum with humbuckers

Discussion in 'Pickups & Electronics [BG]' started by dnp41, Dec 3, 2018.

  1. dnp41


    May 10, 2016
    I have some issues in my home studio set-up, probably due to some not grounded power supplies (although I'm not sure).

    So all basses I have (even humbuckers) with non-emg pickups pick-up hum/static/radio interference. I don't know how to describe it. I tried shielding the pickup cavities of some basses, but that also didn't resolve the issue. What did resolve the issue was.. switching to EMG pickups, either the active or passive.

    My issue now is that I have a new Jazz bass that I love, with Dimarzio pickups. They sound great. But again... the hum thing! I can't record with this bass, and definitely not a clean sound. So my question is:

    Do I change the pickups to EMG JV52's or.... Is there some magical way to solve this issue once and for all?

    Possible causes I can think of:
    - bad power
    - an amateur radio broadcaster across the street
    - mojo is telling me to get EMG's
    - non grounded pickups?
  2. gebass6

    gebass6 We're not all trying to play the same music. Supporting Member

    Might have a ground loop problem.
    Try one of these.
    An Art CleanBOX II Hum Eliminator.

  3. I vote ground loop too.

    Does the problem happen 24/7?
    Is the ham running his station 24/7?

    Bad power? Like from the wall socket?
    Does everything else in your house not work right?

    Does everyone that doesn’t have EMGs have bad hum?

    Everything hums. So all the pickups in all your basses are bad?
    Maybe everything hums because one thing is bad, or...

    You have a ground loop.
    Study up a bit on them and the cures and see if you can apply what you’ve red, to your recording studio.
  4. 96tbird

    96tbird PLEASE STAND BY

  5. dnp41


    May 10, 2016
    Yeas the problem is 24/7. In my house, not in for instance the music store when I test.

    Yes, like from the wall socket. I live in a house from 1970, and only in the kitchen and bathrooms the wall sockets are grounded. The others are not (this is pretty common where I live).

    I have no issues with other electrical equipment, only with basses and guitars not equiped with EMG pickups (either passive or actives).

    It;s not like a 60 cycle hum, a little hard to explain for me, but I can try to record it and upload a sound sample to the site.

    I will definitely read up on the ground loop. I tried the ground loop switch on my recording interface but that dind't make any difference.

    Thanks for the input guys!
  6. dnp41


    May 10, 2016
    Could I use this box directly between my passive bass and my amp?
  7. gebass6

    gebass6 We're not all trying to play the same music. Supporting Member

    It's not powered.
  8. OK...
    So it’s not the ham operator because he isn’t transmitting continuously 24/7.
    Ham radio is not a 24/7 thing like broadcasting.

    Ungrounded wall sockets mean that your equipment is not getting grounded.
    You are probably using those three wire to two wire adapters at the outlets, or have cut the ground pin off of 3 prong cords? This can potentially be very dangerous.

    The outlets in the bathroom, even if they have three prong outlets may not be grounded either.
    You should really get one of those A.C. outlet testers, the ones with the lights that show you if your outlets are wired properly and have grounds at the outlets that do have three prongs. Less than 10 bucks, usually. You don’t need the one with the push button unless you also have Ground Fault Interuptor outlets you want to test.
    This is serious. Do this if nothing else, it could save your life to know if what you think is a grounded outlet is not grounded. You may have hot and neutral backwards on outlets too. This can literally put 115 volts right at your fingertips.

    Have you tried your gear in one of the kitchen/bathroom sockets to see if it makes a difference?

    Not 60 Hz hum. You may be picking up stray magnetic fields on your pickups from other electronic devices. When you are connected and playing, if you move around, or rotate your body, or move the bass from horizontal to vertical, does the sound of the noise change?
    If not hum, you have noise. Hum is one form of noise caused by certain things. Noise that is not hum often has other causes and needs other cures.

    I would not be surprised to learn that you have more than one type of problem going on.
  9. No. I don’t think you can.
    There are two ways to break a ground.
    1. Use an audio transformer.
    The Artcessorie box if it uses a transformer is designed for lower impedance operation. Your bass operates at much higher impedances than what this is designed for. You may get zero to very little signal through it.

    2. Lift (disconnect) the shield connection in a balanced audio line.
    Your bass to amp connection is NOT balanced audio. If you lift the shield on your instrument cable you will get no signal at all and the hum might get a lot worse.
    Last edited: Dec 5, 2018
  10. micguy


    May 17, 2011
    You have one piece of hard data that strongly suggests your other gear is OK - your bass with EMG’s is quiet. Don’t go buying a bunch of stuff to try to solve this just yet.

    EMG’s are low impedance - they are good at resisting electrostatic fields as a result. If you have a bass with them that’s quiet, then your problem is your other basses, not elsewhere in the chain.

    I highly suspect your shielding on your other basses wasn’t done quite right. Most likely, you haven’t grounded all the foil sections, or the pickup shields and/or pole pieces aren’t grounded.
    Last edited: Dec 5, 2018
  11. Are you using audio adapters to convert XLR (3 conductor) balanced audio to two conductor audio using 1/4” or RCA/phono connectors in any of your recording equipment and associated gear?
    If you are, and you don’t understand about interfacing balanced and unbalanced audio, then this may be at least part of the problem. Go ahead and Google -balanced audio- and also -unbalanced audio- this will show you the differences between the two.
    Just because you have an adapter that mates an unbalanced connector to a balanced connector, or the other way around, that does not mean it is a proper interface. Getting this wrong can lead to all sorts of audio problems including hum and other noise. It can also cause signal attenuation which if you have some noise in your audio gear already, may make it worse.

    Audio interfacing is much more complicated than first meets the eye. I know professional sound people (uh well... they get paid to mix audio) who don’t have the foggiest idea about any of this stuff.
    Last edited: Dec 5, 2018
  12. 96tbird

    96tbird PLEASE STAND BY

    Generally, ungrounded wall receptacles have the box grounded, the romex groung wire screwed and terminated to the receptacle box, but no three prong receptacles installed. If you know how to, you can install a grounded receptacle and a jumper wire to the ground on the box.
    Old Garage-Bander likes this.
  13. Yes! Good point.
    Here is one of those adapters.
    Commercial Electric 15 Amp Single Outlet Grounding Adapter, Gray-U-09 - The Home Depot

    The green tab on top goes under the screw on the outlet faceplate.

    You should then use one of these to test to see if you actually have a ground and that the rest if the outlet is wired properly.
    Receptacle Tester-400-029 - The Home Depot
    96tbird likes this.
  14. 96tbird

    96tbird PLEASE STAND BY

    I had forgotten those existed. Cool solution for the home unhandy but not elegant. Its a carbuncle :roflmao:

    I prefer to pull the receptacle and swap in a modern. My house is 1942 and I have done several where needed.
  15. I use those adapters all the time at work to break ground loops for remote broadcasts or as a TEMPORARY diagnostic of a ground loop problem. (Boys and girls, do not do this at home.) I use them so much to break grounds that I forgot that their real purpose is for adding grounds.

    For the OP, I would have thought that house a built in the 70’s would have had grounded outlets. Wasn’t the use of aluminum house wiring a big issue from that era? Not necessarily for grounding reasons, but more of a fire safety thing?

    The best part is you saying “carbuncle.” :laugh:
  16. gebass6

    gebass6 We're not all trying to play the same music. Supporting Member

    From the site:ART Cleanbox II |

    The ART Cleanbox II is a simple and affordable stereo isolation box containing two isolation transformers designed for line-level use, with quarter-inch jacks in and out. Both the inputs and outputs are unbalanced, but are wired to accommodate balanced or unbalanced connections on TRS jacks. Because transformers are passive devices, and because no other active circuitry is needed, there is no need for batteries or a power supply, but there is a small insertion loss of three or four decibels in typical applications.
    Last edited: Dec 5, 2018
  17. “designed for line level use”
    The typical bass output is instrument level.
    IMHO, 88 bucks is a lot of money to spend on twice as many transformers as you need that may not work well anyway. Especially when only guessing that this may solve the problem.
    gebass6 likes this.
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