60 cycle hum grounding issue, or something else?
 

OK, so I've searched and haven't found the answer I'm looking for. I know there's a lot of info here on jazz pickups and unwanted noise, but I've found some conflicting opinions on my issue. I have a noisy Jazz bass, and I'm not sure if its 60 cycle hum or a grounding issue. Here's my setup:

MIM Jazz V deluxe
Lakland Hanson single coil pickups
Audere JZ3d preamp

I dont remember the noise being as bad with the stock preamp. I have already shielded the control and pickup cavities, but it might not be the best job. I ran out of copper tape and finished it in aluminum. The noise is loudest when I'm facing the amp. It disappears when i turn roughly 90 degrees from amp, then comes back when I face away from amp. There is no difference in the noise if I'm touching the strings or not. I know it's the bass because when I use another bass with the rest of my rig- no noise.

So what the solution? Need better shielding? Hum canceling pickups? Grounding the pole pieces on the pickups? Is there a grounding issue somewhere? Preamp issue? Something else?

Thanks TB!

Does all of your shielding have continuity?
Is everything grounded properly and preferably in the same spot?
Is the bridge ground hooked up?

The noise isn't caused by the audere but it is so transparent that is exposes any week spot.
What kind of Pups? Oakland right

Mike

Yes, there is a ground wire to the bridge, and I think it's properly grounded. Continuity between the pieces of shielding may be an issue. I'll check when I get a chance. But touching and letting go of the strings makes no difference in the noise. Does this mean its not a grounding issue?

The hum is because of the single coil pickups. Shielding does not fix 60 Cycle hum. It only takes care of the high pitched buzz you get from electrical field noise. Only hum canceling pickups get rid of 60 cycle hum. Grounding and shielding only fix the high pitched buzz.

Do those pickups hum cancel when you have them both on?

You kept the shield ground and the pickup grounds separate going into the Audere, right?

Sgd is correct. I assumed you are panned to the center? So check your continuity, because if you don't have it you don't have a sheild. You have just copper tape. It will help with some noise. Just not the 60 cycle from your pups.

No, there's still noise when they're both on. I'll have to check on the shield and pickup grounds too.

>Shielding does not fix 60 Cycle hum

Shielding can reduce with 60 cycle noise if the coupling is by an electric field.
See Pickup Shielding in our FAQs and the scope displays at the bottom of the page.
The scope displays were taken without a preamp.

Non grounded shielding can make the noise worse not better.

If the coupling is by a magnetic field then shielding will not be helpful but dual coil hum canceling pickups can help.

The same conditions apply with or without a preamp.

David

You're correct, of course, but I was just stating that because some people seem to think that shielding single coil pickups stops them from humming. Since the shielding won't stop magnetic field interference, they will still hum, but it can help somewhat.

Plus the majority of pickups on the market, both single coil and humbucking, are not shielded.

Thanks for the knowledge boost! Very informative. And timely - I had my interest piqued in this subject by Roger Sadowsky (and others) on a similar thread and then I immediately saw this one before I had a chance to research it at all!

Ok, so I guess I'm not sure if I'm hearing 60 cycle hum or something else. The hum is strongest when if face the amp and lessens when I turn away. Is that 60 cycle hum?

Sounds like it. Is it low pitched?

Hum induced in pickups is directional because the pickup coil is sensitive at certain angles and not so much others.

Other kinds of noise are not as directional. For example, pull the plug out of your bass and touch the tip. The buzz you hear does not change when you change direction.

Thanks, yeah it's lower pitched. Seems to do it in different locations in the house and different gigs too. At least I know my shielding continuity is OK- tested it yesterday. But it is grounded to the same ground as the preamp. I didn't even think about it when I installed it last year. But of they need to be grounded separately, where would I ground them?

Regardless, sounds like some hum canceling pickups are in order. Too bad because I love the tone I'm getting out of these Lakland Hansons.