Jazz bass pickups or J bass pickups are one of two main types of magnetic pickups used in electric bass guitars. A typical jazz bass pickup consists of a coil of wire wrapped around a set of magnetic polepieces.
Jazz bass pickups usually employ two pole pieces for each string — eight pole pieces for a standard four string bass pickup.
The other type of magnetic pickup commonly found in electric bass guitars is the Precision bass pickup or P bass pickup which employs two separate coils. The J bass pickup typically offers a smoother, brighter and richer tone in the treble and midrange compared to the P bass's more deep and thumpy bass-heavy tone.