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Changing a Passive Bass to an Active Bass

Discussion in 'Pickups & Electronics [BG]' started by Mark Wilson, Aug 21, 2005.

  1. Mark Wilson

    Mark Wilson Supporting Member

    Jan 12, 2005
    Toronto, Ontario
    Endorsing Artist: Elixir® Strings
    Hey everyone.
    I was wondering...I have a Standard Fender Fretless Jazz, and i am getting very aggravated at the buzzing i get from it. I've talked with a music store around here. And he suggested either getting a noise supressor pedal or something, or invensting on switching from passive to active.

    Which to you guys suggest? Keep in mind, i know NOTHING about electronics and pickups. If someone could explain what a pre-amp does in an active bass, that would be great too :D

    Also, will I have to change the look of my bass?


  2. Ok...basic school lesson...noise usually comes picked up from RF (radio frequency) interference...

    Good grounding of all components and shielding of body cavity is paramount...

    the next step is dealing with your cable...one way to help this is to go active...by putting a preamp in your bass, you can essentially "buffer" the pickups from your cable...then they don't work in tandem together and this can help...but that's not the first place I would look when tackling a noise problem...

    Your pickups are most likely single-coil and these coils pickup noise where hum-cancelling or "humbucking" pickups use coils that are counterwound in close proximity to each other to negate the noise and this WORKS...

    also a pedal or an amp with a ground lift switch would help on the ground loop noise (noise not picked up from RF but through the AC voltages of the amplifier).

    Things to do in order of expense vs. effectiveness

    1. Good grounding/shielding of components and control cavity
    2. Noise cancelling pickups
    3. Box with a ground lift switch (only good for Ground Loop issues)
    4. active electronics (cheap if you are a DIYer...expensive if not)
  3. Mark Wilson

    Mark Wilson Supporting Member

    Jan 12, 2005
    Toronto, Ontario
    Endorsing Artist: Elixir® Strings
    Hey man, thanks for the tips. The Ground Lift button on my amp made no difference :\
    But I think I am going to get some Active's in there. Thanks again
  4. David Wilson

    David Wilson Administrator Staff Member Administrator Supporting Member

    Oct 14, 2002
    Lower Westchester, NY
    again, as Pilbara said, just putting a preamp in there won't solve your problems alone.

    You have single coil pickups in there, which will produce hum when they are not both on full. You can invest the time/money on shielding/grounding and/or get humcancelling pickups in there.
    If you look in the pickups faq, you'll see a link to a thread of mine where I recorded over 10 different pickups in a Geddy Lee Jazz.
  5. MJ5150

    MJ5150 Terrific Twister

    Apr 12, 2001
    Olympia, WA
    You owe it to yourself to set aside some time to read this, as well as the review done by SMASH. I read both completely before I addressed the problem you are having.

  6. BassyBill

    BassyBill The smooth moderator... Gold Supporting Member

    Mar 12, 2005
    West Midlands UK
    Standard J pickups are single coils, as David said, and will only cancel hum when both pickups are on at pretty much the same volume. I guess the hum you're noticing is more prevalent when either one of the pickups is soloed?

    Several manufactureres make passive, hum-cancelling versions of the J pickup as direct same-size replacements. The links above will give lots of info on these, and I suggest you also look at Carey Nordstrand's site www.nordstrandpickups.com Some of the pics on there will give you an idea of the construction differences between true single coils (like his NJ4) and the hum cancelling versions (NJ4SV for "vintage", NJ4SE for a more "modern" type sound - I have the latter in a fretted J bass and believe me they are GREAT pickups for that type of sound). I know Mike is also a fan of the Nordies.

    Another option is to go active, by which I mean actual active pickups like EMGs rather than adding an active pre-amp to passive pickups like the ones you already have. EMGs are the quietest pickups noise-wise I have ever used, and I love the hi-fi, high clarity sound of the EMG Js in my fretless, although they do need a little bit of EQ tweaking to really bring the midrange out. Have a listen to this sound clip to see what you think. Ironically, there is some hum on the clip! Don't worry about it, this was caused by the crappy little unshielded lead I used to plug the bass straight into my PC soundcard (yes, right next to the monitor). As I said, in normal use with a proper lead, the EMGs are DEAD quiet.

    Let us know what you do and how it turns out. ;)
  7. Zebra


    Jun 26, 2005
    I'd suggest you get humcanceling pickups. Shielding/grounding will help, won't cost much and isn't major, but there will always be hum with those single coils. Give the shielding a shot, but new pickups may be necessary to totally eliminate it.