60 cycle hum and shielding

Discussion in 'Hardware, Setup & Repair [BG]' started by rabid_granny, Feb 9, 2002.

  1. I'm a bit confused by some other posts. Will shielding reduce the 60 cycle hum of a single coil pickup?

    I'm not sure if the other posts are referring to the usual buzz from bad grounding or the 60 cycle hum.
  2. 60 Hz hum, can be overcome by earthing your amp properly. Open it up and where the mains cable comes in there should be a green and yellow wire that is bolted to the chassis. Make sure it is tight and makes good contact. Any points that are earthed, check.

    In your bass do the same thing. Any green wires that are soldered or screwed down, check they make good connection.

    Are you using balanced outputs to your speaker (s)?? As in a XLR/canon socket? Make sure the earth pin (not sure what it is in your country, sometimes its pin 1 others pin 3) is soldered properly onto it.


  3. I haven't purchased a jazz bass YET but I'm getting pretty close. The reason why I posted this thread was to see what I could ask the music store to do, before I purchase the bass.

    I don't know enough to fiddle around with the innards so I figured if I knew what to ask for, they could do it for me.

    Some of the jazz pickups I tested had a god-awful hum...there's gotta be a way to minimize it, without resorting to active pickups...
  4. You can't completely shield a bass with magnetic pickups - they wouldn't make any sound if you did.

    Jazz basses have single coil pickups and the neck pickup is reverse-wound with reverse polarity to cancel hum. I believe Fender does the same thing with p-bass pickups.

    Assuming the bass is properly shielded you're just gonna get some hum on a Jazz bass - the hum comes from flourescent lights, neon signs, your amp's transformer and any passing spacecraft.

    You certainly can complain about the hum and have the bass checked out before you purchase it. Although most all Jazz Basses hum to some extent, if the hum's excessive with both pickups turned up, have the bass looked at.

    Most people who play a Jazz Bass (myself included) either put up with the noise or replace the pickups. I did the latter - replaced them with a pair of quad-coil Bartolinis. No hum.

    Fender puts "noiseless" pickups in their American Jazz Bass Deluxe - I think you can also get them separately from a Fender dealer.