Pickup hums when I touch the poles

[Mr. Foxen]

I've just put a 1/4 pounder (p style) in a bass, all works fine, but on one half I get a hum when I touch the polepieces, but not on the other hald, is some sort of shield or earth disconnected? It also hums a bit through the amp, but not loads.

[BOD2]

Check the wiring first of all. Is it just the quarter pounder you have in the bass or are there any other pickups ?

The correct wiring diagram for a P-Bass is here [url="http://www.seymourduncan.com/support/wiring-diagrams/schematics.php?schematic=std_pbass"]P-Bass Wiring[/url].

In particular, check the ground wiring. If you grounded the pickup to shell of the volume control (as shown) make sure it's a good connection (nice and shiny - not dull and grey).

[Mr. Foxen]

Its just a single P style pup, volume and tone. And its only one half that does it, mostly when playing, its a click when you touch the pole. Although I used this diadgram: [url="http://www.guitarelectronics.zoovy.com/product/WDUPH1101"]http://www.guitarelectronics.zoovy.com/product/WDUPH1101[/url]
which has the capacitor on a different leg, which is pretty irrelevant. Since there ar only two wires comin out of the pickup, if one wasn't connected, it just wouldn't work, and why would one half be different to the other?. Gonna just have to tape over them for the moment.

[BOD2]

Yes the wiring diagrams are effectively the same.

All I can suggest is that you check all the ground connections and make sure they are all good.

I'm assuming that both halves of the pickup have equal output ? One easy way to check this is connect to an amp (keep the volume fairly low) then to take a small screwdriver and very lightly tap each polepiece in turn. You should get a clear "click" from each of about the same volume.