on a hum i got it has 3 wires. a red a white and a bare one. I know the bare one is a shield wire, but which one do I ground?
Doesn't matter. But for the sake of keeping things in correct polarity (If you have another pickup about 1 1/2 inches away from it or closer), the red is usually the "hot" and the white is usally the "ground".
so will hooking up the shield wire make the pups sound different