Hum that dissapears when you touch the output jack

[jacobtm]

I've got a Warmoth P/J bass which I wired up according to this link: www.seymourduncan.com/support/schematics/p-j_bass.html

For a while, it was fine, but recently, I've begun to get this annoying humming. The humming goes away completely whenever I touch the control plate (which is metal), or the output jack.

Does anyone know what might be causing this and how I might fix it?

Thanks alot,
Jacob

[JohnH]

As Zjokka suggests, some kind of grounding problem is likley. As a simple test, if you wrap or clip a wire externally to a known grounded point, such as the metal barrel of the jack plug, and also connect it to the bridge, or the control plate, does that fix the hum? As you do this, dont touch the metal yourself. If that test fixes it, then you can open up the bass and make an equivalent permanent fix.

[ajent__smith]

i agree with John H, it is most likely a grounding problem. I would suggest grounding your bridge to silence the hum if not already done. that way, whenever you are toutching the strings you are grounding yourself out, making your self a sheild, not an antenna for hum.