This is the second in a series of blog posts on guitar pickups. The intent is to present the info in a way that's informative to someone who might not know anything about pickups, but is still interesting to those more familiar with them.
In my last blog post I gave a historical summary and brief overview of the various types. In this post we'll look more closely at single coil pickups.
At their simplest, single coils are the most basic and widely used pickup on the market. Originally, they used a relatively simple design consisting of a fiberboard bass & top, magnetized pole pieces, copper wire, and usually wax (dipping a pickup in hot wax allows the voids inside the pickup components to be filled, thus eliminated unwanted microphonic feedback). Over the years there have been a number of developments that have opened up more possibilities. One of the biggest reasons for innovation in the single coil pickup is the constant issue caused by 60hz hum from electrical outlets (if you care to read more on this topic here's a more in depth article from a source more knowledgeable than myself). One of the most basic developments is the idea shared with a humbucker:
Reverse winding/reverse polarity (rw/rp): a simple concept to help solve a nagging issue. Matching two single coils with one rw/rp pickup eliminates the noise from 60 cycle hum when both pickups are used together. In a Stratocaster model, an rw/rp pickup is most often used in the middle position allowing hum cancellation in the "notch" positions (ie positions 2 and 4 on a 5 way switch). The same concept applies to any other two pickup style guitar (Tele, Jazzmaster, Jaguar, dual P90 equipped guitar, etc), with the hum cancelling occurring only in the middle position on a 3 way switch.
These were a way to achieve a nearly noiseless sound out of a single coil sized pickup by itself, while still retaining the basic tone associated with vintage style single coils. Building on the same idea many other manufacturers would begin to build their own version of noiseless single coils including Fender (SCN & N3), Seymour Duncan, Dimarzio Lindy Fralin and others. While the designs vary slightly from builder to builder, the concept is the same: to build a single coil sized (and sounding) pickup that eliminates 60 cycle hum!
Single coil sized humbuckers
Similar to the Lace Sensor style of pickup, manufacturers also started to build single coil sized humbuckers. In one sense, these are the same as noise cancelling single coils in that they cancel hum, but in another sense they're quite different. While noiseless single coils are intended to retain vintage "single coil tone," a single coil sized humbucker is designed to provide the tone of a humbucker in a single coil housing. Tonally speaking a humbucker is a beefier sounding, higher output pickup compared to a traditional single coil. Many manufacturers now make some version of these such as the Seymour Duncan JB Jr.
Active single coils
As active pickups began to grow in popularity, single coil models of active pickups also became more widely used. An active single coil retains a lot of the sparkle, clarity and punch that single coils are typically known for while allowing for higher output and noiseless operation. These provide a very different tone that's widely used especially in heavier and more modern styles of music. EMG's SA Active Single Coil is a popular example of this style single coil.
While most of what I've referenced in this post references Strat style pickups, the same concepts and design are used for Tele pickups and in some instances other lesser used single coil designs.