Humbuckers like this Seymour Duncan SH-16 ’59/Custom Hybrid are basically two side-by-side single-coil pickups wired together to reduce extraneous noise and offer a more powerful sound.
PickupsAcoustic transducers: A transducer is a device that turns direct vibrations into an electrical audio signal. Any contact pickup, including the under-saddle piezo pickups found on many acoustic guitars, fits this category.
Active vs. passive: Standard magnetic pickups such as those on the earliest electric guitars on up to the majority of electrics today are passive devices. Their magnets react to the string vibration to create a very low-voltage electrical signal, which must be boosted with a preamp (like the first section of your guitar amp) before it’s strong enough to push a power amp and speakers.
In contrast, active pickups have internal preamps, which use an onboard power source (often a 9V battery) to both boost output and lower impedance. This can have several advantages: First, the signal degrades less over a long cable run, there’s less interference, and you can push your amp’s input harder for more overdrive. However, active pickups also have their own sound, which some people love and others don’t. They’re more popular among bass players and metal guitarists, though they’ve also been in David Gilmour’s guitars for many years.
Coil-splitting vs. coil-tapping: Coil-splitting is when only one of a humbucker’s two coils (or sides) is used on its own to offer a true single-coil sound. Coil-tapping is when a signal is taken from a point somewhere within the vertical windings of both of the humbucker’s coils to offer a single-coil-like sound. In other words, it’s still using both coils/sides, but it’s feeding only part of the full, dual-coil array to the output. See also Humbucker.
Humbucker: See also Single-coil. Essentially, a humbucker is two single-coil pickups (the earliest pickup design) wired together to eliminate (or buck) the extraneous noise (hum) often present in single-coils due to electrical interference from nearby lights, computers, power sources, etc. Another sonic characteristic of humbuckers is that they typically offer a fuller, more powerful and/or aggressive sound that many players prefer for hard rock, metal, or meatier blues and jazz tones. Humbuckers typically look like two side-by-side single-coils, but they can also have a stacked-coil form factor in order to fit standard single-coil pickup cavities or pickguard routes.
Although Stratocaster-style pickups like the Fender Texas Specials shown here are probably the most popular single-coils, there’s a huge variety of single-coils with widely varying tonal characteristics on the market.
Magnets used in the construction of electric-guitar pickups play an important part in their overall tone. They come in several varieties.
Ceramic magnets are made from ferrites (iron oxides). In general, ceramic pickups are known for their high output and aggressive tone, making them especially popular for metal.
Alnico is an alloy of aluminum, nickel, and cobalt, and pickup designers use various alloys with differing amounts of each element to achieve varied tonal characteristics. Compared to ceramic magnets, alnicos tend to sound sweeter and smoother, with lower output. For guitar pickups, the two most popular alloys are alnico 2 and alnico 5. You’ll also find pickups with alnico 3 magnets. Alnico 2 contributes to the signature tone of Gibson’s famous PAF humbucker (and countless other pickups), while alnico 5 tends to sound a little more aggressive. Interestingly, alnico 3 doesn’t fall somewhere in between: With less cobalt in the magnet, these are actually the mellowest member of the family.
Note that while most pickups use separate magnetic pole pieces (the exposed, smooth-topped circles visible on top of most pickups) wrapped in wire, some use a bar magnet, with either no pole pieces or with steel poles contacting a magnet on the underside of the pickup. A famous example of the latter is the P-90.
Single-coil: See also Humbucker above. Technically, a single-coil pickup is just that—a pickup with one coil of wire wound around a magnetic bar or set of pole pieces. They come in many forms—from narrow Strat-style to the fatter Telecaster bridge pickup, the even bigger P-90 (known for giving a Les Paul Junior its distinctive bark), the Jazzmaster’s bright-sounding rectangular pickups, and the metal-encased lipstick pickups made famous by Danelectro— and though each has quite a distinctive sound, in general they tend to offer brighter tones that often translate intricate picking nuances better than a humbucker.
Starting in the 1970s, however, the idea that form factor and sound were synonymous began to change. Today you’ll find plenty of sonic variation in each shape: Strat pickups wound to sound like Tele pickups, or Tele pickups with P-90-style steel pole pieces. Making things more complicated is the explosion of hum-cancelling (stacked-humbucker) pickups designed as drop-in replacements for traditional single-coils.