Pickup Basics

“WHAT GIANT POLEPIECES!” “HOW ’bout a humbucker?”
By Brian Fox ,



Fig. 1“WHAT GIANT POLEPIECES!” “HOW ’bout a humbucker?” Okay, so I’ve never been great at pickup lines. But if you’re thinking about anything other than those rectangular (or oval) gizmos sitting under your strings right now, pull yourself together and familiarize yourself with that most crucial stage of any electric bassist’s signal chain, the pickup. Settle down and wrap your brain around this basic introduction.

FROM VIBES TO VOLTS

With electric basses, amplification of a string’s acoustic sound is the name of the game. That sound comes from a string’s vibration. A pickup reads that vibration by way of an electromagnetic field created either by pole pieces—the round metallic dots you see in the Fender Jazz pickup in Fig. 1—or by a bar magnet at the base of the pickup. When the movement of a metallic string disrupts that electromagnetic field, it creates a current that is conducted by the copper wire surrounding the magnet and sent along shielded wire to a set of onboard electronics. These electronics can be as basic as a single pot to control the volume or as elaborate as a battery-powered circuit with dozens of tone controls. That signal is then passed on to the bass’s jack, and then on to an amplifier via an instrument cable.



Fig. 2SINGLE FILE

Though all magnetic pickups operate on this same basic principle, there are a few key differences to be aware of. In a singlecoil arrangement (like that of a Fender Jazz pickup) a row of polepieces is wraped with a single length of wire. Single-coil pickups are often-praised for their punchy midrange and clear high-end response.

HUMBUCKEROOS

In a humbucking design—so named because of its ability to eliminate the 60-cycle hum that can be an issue with single-coil pickups— two or more rows of magnets are wrapped with multiple lengths of wire in alternating directions. The Fender Precision [Fig. 2] and Music Man StingRay [Fig. 3] pickups are classic versions of the humbucker. Compared to single-coil pickups, humbuckers tend to have a darker sound with a more subdued high end.


Fig. 3PICKUP PIECES

Pickup type—single-coil, humbucking, or otherwise— has a big impact on a bass’s sound. But so do the finer details like the materials used and the number of times the wire is wrapped around the magnet. Of course, a bass’s preamp can have a massive impact on a pickup’s character.