Active Guitar Pickups
Active guitar pickups require a power source to function, which is usually supplied by an internally mounted 9-volt battery. By using an active voltage source, such pickups can be more complex in nature and can also offer a more powerful signal, of a higher fidelity.
Another benefit of active pickups, for those who enjoy them, is their low-impedance signal, meaning their output can survive long cable runs without loss of high-end content.
Les Paul, the guitarist — who was very much an inventor as well as a musician — was a major advocate of active, low-impedance pickups, and he insisted on them for his Les Paul Personal, Signature, and Recording model guitars from Gibson in the late ’60s.
One of his reasons for preferring such pickups was the ease with which they could be plugged straight into the recording desk, without need of a traditional amp, to achieve a clean, high-fidelity sound.
Active pickups also yield unprecedented output levels and extreme sustain, characteristics that have made them popular with many guitarists at the other end of the spectrum, where hard rock and heavy-metal artists ram them into big, powerful amps to generate massive distortion levels that nevertheless retain a big, firm low end.
They’re generally made in the same shapes and sizes as the most popular passive pickups — so they’re easy replacements for traditional humbuckers, P-90s, and Strat and Tele single coils — but usually have uniform plastic covers with no visible pole pieces.
Pickup manufacturer EMG (short for Electro-Magnetic Generator) is far and away the most popular maker of active pickups on the market today. Its humbuckers in particular have set the standard for high-octane metal tones, and they’re in use by guitarists such as Zakk Wylde, James Hetfield, and Kirk Hammett of Metallica, and Kerry King and Tom Araya of Slayer.