Re: Wiring Problem?!?! (expert help needed)
Yes, you need to ground the sleeve terminal of the o/p jack.
If you have aluminium foil on a plastic plate, this will provide an earth connection but not a very reliable one. Use some patch cable to link all the pot casings and the sleeve terminal. Even a metal plate does not provide as reliable a source of contact as a solder joint.
You may find, on the Mustang, that there is no cavity shielding. If you are using unscreened point to point wiring between the pots and output then it doesn't matter how good your 'bucker is or whether you have screened cable on the output wire, the lengths of unscreened cable in the cavity will pick up r/f interference.
As a matter of good practice, I generally get a length of nickel silver wire and solder it across all the pots and the o/p jack if possible to create an earth rail. This allows cable screening to be tacked to earth at many diferent points and has the additional benefit of tying the pots and jack together physically so that if anyone comes loose it can't rotate and chew up the wiring.
Oh, and remember there should be a wire from the bridge to the pot casings.
