I have a hum only when I turn the knob toward one pickup. I found this answer on the web, i this true? How do I know if my J is a single coil. And if this is true and my J is a single, isn’t that a shitty way to make a bass? I’m confused, but right now I use one pickup as I can’t stand the hum.
To give a bit more detail to what the others have said, you want a split coil Jazz pickup. The two halves of the P pickup are wound and biased so that they humbuck. A split coil Jazz pickup is made the same way internally but you can’t tell the difference from the outside, they look just like single coil Jazz pickups. Dual coil hum canceling Jazz pickups are also available but the split coil pickups sound closer to the single coil tone, minus the hum.