DiMarzio Ultra Jazz Hum Problem

[syddd]

I have DiMarzio Ultra Jazz split coil J-Bass pickups installed in my bass, and I have the split coils wired in series to each other for each pickup. They are meant to be hum cancelling, however whenever I touch the magnets for the split coil underneath the E and A strings, it emits a loud buzzing sound. Pressing the magnets for the other coil does not have the same effect. 

Is there any way that this is a wiring issue, or is this a straight up pickup defect, given I have not disassembled the pickup at any point?

[okabass]

Grounding the magnets with a copper foil could help.
www.audereengineering.com/FAQ_PUMag_Gnd.htm
Are the PUs wired correctly?
www.dimarzio.com/sites/default/files/diagrams/ultrajazz2v2t.pdf

[syddd]

Jun 9, 2018 17:01:12 GMT -5 okabass said:

Grounding the magnets with a copper foil could help.
www.audereengineering.com/FAQ_PUMag_Gnd.htm
Are the PUs wired correctly?
www.dimarzio.com/sites/default/files/diagrams/ultrajazz2v2t.pdf

I will consider grounding the magnets, it would mean removing the silicon from under the pickups however. The pickups are wired correctly (white to black, green to ground) Interestingly I got the following response from DiMarzio on this;


I think the pickups are performing normally. The magnets of these pickups are not grounded. This can cause a buzz when the magnets of the coil you described as the hot coil are touched. This is usually not an issue in actual performance, because the noise is not audible if the strings are touched by either hand at the same time, which is almost always the case. The only situation in which touching the strings will not remove the noise is if the bridge is not grounded. I assume your bridge is grounded, but this is the first thing you might check. You might also be able to reduce the noise by trimming the pickup wires short, because excess wire in the control compartment can act as an antenna for noise.

This is really strange to me, why wouldn't the magnets be grounded by design? What happens for the more traditional split coil P-Bass pickups?

[newey]

DM's guy sez:

This is usually not an issue in actual performance, because the noise is not audible if the strings are touched by either hand at the same time, which is almost always the case. The only situation in which touching the strings will not remove the noise is if the bridge is not grounded. I assume your bridge is grounded, but this is the first thing you might check

I think you should verify whether you are experiencing this problem even despite touching the strings at the same time, and if so, test your bridge for proper grounding.

This part:

You might also be able to reduce the noise by trimming the pickup wires short, because excess wire in the control compartment can act as an antenna for noise.

Doesn't make much sense. An inch or two of excess wire isn't likely to cause much noise, and if it did, it would be noise generally, not just when you touch the pickup.

[okabass]

Jun 10, 2018 21:28:23 GMT -5 syddd said:

Jun 9, 2018 17:01:12 GMT -5 okabass said:

Grounding the magnets with a copper foil could help.
www.audereengineering.com/FAQ_PUMag_Gnd.htm
Are the PUs wired correctly?
www.dimarzio.com/sites/default/files/diagrams/ultrajazz2v2t.pdf

I will consider grounding the magnets

The pickups are wired correctly... white to black,   
 

I believe grounding would help.  Is the white to black connection taped, so it can't touch anything metal.