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RF or electromagnetic buzz/rizz

Discussion in 'Pickups & Electronics [BG]' started by Lorenzini, Dec 4, 2013.

  1. Lorenzini


    Dec 31, 2004
    Los Angeles
    My 55-02 has RF / electromagnetic buzz/rizz. It's not 60 cycle hum, but buzz/rizz.

    Anyone know if this is due to improper grounding, or the bass needs better shielding, or maybe I even missed a wire?

    I know what 60 cycle is, and this isn't it. It only occurs in funny RF / or around power sources, those things which would cause electromagnetic interference.

    Thanks all.
  2. You won't hear any RF content. That's well above the human hearing range.

    Sounds like electrical field noise. Check over your shielding and grounding scheme, and be sure that everything is electrically continuous.
  3. Lorenzini


    Dec 31, 2004
    Los Angeles
    Okay cool.

    Electrical field noise sounds about right. I'll check out how it's wired.
  4. mattattack187

    mattattack187 Bass Enthusiast Supporting Member

    Feb 2, 2012
    Bangor, ME
    I had some nasty interference going on last night on all my basses couldn't for the life of me figure out why. Then I remembered the space heater was on at the moment.....
  5. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism Supporting Member

    My money is on shielding as well
  6. Lorenzini


    Dec 31, 2004
    Los Angeles
    Shielding or an improper ground?

    I pretty much followed the diagram to a T, and now I'm running into this.

    Another piece of information is, these are single coil MM/J pickups. The humbucking MM/J's did not have this problem, with exactly the same wiring schematic.
  7. What do you mean by single coil MM/J pickups? MM pickups are always dual, triple, or quad coil, never single.

    If there are an even number of coils in pairs of matched outputs, then electrical field noise induced in the coils will cancel out with itself. However, it can still be present where it is induced into other parts of the circuit.
  8. two fingers

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

    Feb 7, 2005
    Eastern NC USA
    Yeah I'm going to need clarification on "single coil MM" as well.
  9. Lorenzini


    Dec 31, 2004
    Los Angeles
    Good question guys :)

    They are literally 2 single coils right next to each other.

    So essentially it's a JJ/J bass.
  10. bassbenj


    Aug 11, 2009
    Yes. Not all electrical noise is hum. Some is higher frequency buzz of modern high frequency power supplies (like computers fer sure) or harmonics of powerlines. It still works the same way, however.

    So there are two kinds of hum. Electrical hum which shielding will cure and single coil hum which shielding will not cure. Only humbucking pickups will cure that.

    So the way you find out if you are picking up electrical noise is to touch the strings or other ground (jack body). Does the noise go away or change volume? If so, it's electrical noise and that means either the bass needs shielding or the shielding in the bass has come ungrounded.

    Sincle coil hum will not change when you touch ground. But it WILL change as you move the orientation of the bass around. Often you can find a "null" position for the bass (not necessarily playable) where the hum/noise is minimum.

    It's likely you have the latter. Why? Because you have an MM/J setup. The MM pickup is typically a humbucker. And the J (unless it's "noiseless") is single coil. Thus, you can never get all the hum cancelled if you use both pickups. A Jazz bass uses two single coil pickups that are made to be a humbucker (like the MM) when BOTH are on full. With yours this can't happen because the JJ is humbucking and the J probably is not.

    But first make sure there is not a shielding problem. Because single coil hum is a LOT less irritating if all the electrical noise is removed by shielding first!

    As for high frequency buzzes, There used to be some kind of electrical equipment in my neighborhood (I suspected some kind of commercial welder) that would come on during the day and get into instruments and radios etc. I searched the neighborhood with a transistor radio trying to find the culprit but never could. Then it stopped by itself. Such is life.
  11. That's the way all traditional MM pickups are made. And for that matter, the most common design for humbucking pickups in general.
  12. Lorenzini


    Dec 31, 2004
    Los Angeles
    Thank you, and this clarifies a lot.

    The hum doesn't go away when I touch the strings.
    Rather, it is what you say about finding a "null" position for the bass, and of course, this noise is better in some environments than others.

    Apart from shielding, what I am really trying to figure out is:
    Did I wire the bass up incorrectly, did I mis-solder a ground?
    I really don't think I did, as I followed the diagram PERFECTLY.

    No, the bass is not even close to shielded. It's completely bare inside due to the original bass design of completely humcancelling pickups.

    At this point I'm not sure if it's wisest for me to bring the instrument to a reliable tech who will shield the bass professionally, or just do it myself.

    Your help is very appreciated.
  13. Lorenzini


    Dec 31, 2004
    Los Angeles
    I suppose I'm not as genius at this as I had suspected ;)

    But there is something different about these new pickups Lakland/Hanson sent me versus the original humbucking MM/J set. Do you know what that might be?