Right guys heads up.Things are tight money wise,so I decided on a Wilkinson humbucker from a company in China, who were on Ebay.It arrived yesterday,packed like Fort Knox, and I installed it today.Wiring had me a bit perturbed tho'.Black,yellow and red and white,which were soldered together.I naturally presumed that the black was ground, and the yellow would then be hot,but that put both pickups out of phase.So reversed the connections and that worked OK,except that I now have a slight buzz when I'm not touching the strings,but only on the new pickup.I presume that it will have to be earthed now,but I dont see an earth wire.There is an ARTEC SE3A pre-amp installed in the bass,by the way.That may or may not be important.How do I ground this new pickup?