A long long time ago, when I was a very young child, the whole family used to gather ‘round the fireplace and in between singing church hymns and season appropriate show tunes, we’d turn on the ol’ picture box, now more commonly known as a television, and while my father would curse every other commercial that came on because he felt they didn’t show him enough respect, I would be mesmerized by the five seconds or so that I could catch of the guitar greats of my day. There was Junior Barnard, Oscar Aleman, George Van Eps, and who can forget Charlie Baty from Little Charlie and the Nightcats! Those guys could swing and jazz dance the Charleston like no other!
All flashbacks aside, the first thing I remember asking myself was “how can an electric guitar sound like it does?” Distortion was a complete mystery to me at the age of six or so and had no idea about amplifiers and effects. Anyways, back here at the modern age, I quickly discovered that besides the guitar itself and the amplifier/speakers, there was something in between the two. That, obviously, is the pickup! Plenty of you music fans know about these little suckers like the back of your hands, but for everyone else out there looking to know a little more, read on as we give you an introduction to the magnetizing world of the pickup.
The Basics of the Modern Magnetic Pickup
String effect on coils read by meter
For those of you unfamiliar with the workings of a standard electric guitar pickup, essentially they consist of a magnet that is wrapped around thousands of times with copper wire, creating a coil around the magnet. When a string is plucked, the inherent magnetism of the vibrating metallic string (usually nickel plated) causes a modulation, or change in frequency, in the magnetic field of the coil which creates an alternating current.
Essentially, this means that plucking a guitar string causes a magnetic shove of sorts to the copper in the pickups which then causes the magnetism in the copper to push back a magnetic signal of its own (we’ve all played with magnets and noticed how they push back if you have them facing a certain way, same thing). That signal created is what is sent over to the amplifier through the guitar cable. Not too hard, right?
Sometimes there might be a pre amplifier that is located between the actual pickup and the output cable which is used to give the signal a certain trait or effect (usually compressors or signal amplifiers) before it is sent out through the guitar cable and into the amp.
The Two Main Types of Magnetic Pickups
The Single-Coil Pickup
This is the grand-daddy of pickups; they were the first ever made commercially available which would introduce the world to the electric guitar. These guys were first made by George Beauchamp, a guitarist and Los Angeles native who in the mid ‘20s was trying to find a way to make guitars amplified with the idea of using something much like what made phonographs work. After experimenting with phonograph pickup assembly, he replicated the construction of the pickup using magnets of different sizes and wrapping coils around them in many different combinations. He first used a washing machine motor as his permanent magnet and wrapped coils around it, later switching to smaller sewing machine motors, and eventually to the single coiled magnet which is the basis of pickups to this day.
Gibson would later improve on the design by placing a thin blade of metal in the middle of the magnet with the edge facing the strings sticking out a bit which in effect worked like today’s separated pole pieces, giving the pickup a more effective way of picking up the vibrations. These types are known as “bar pickups” or “Charlie Christian pickups” when referring to the Gibson models.
By 1946, Gibson had introduced the P-90s, single coiled pickups much like the Charlie Christian models but had six adjustable pole pieces, on for each string, instead of the single blade design. The separated pieces gave it the advantage of being able to modify how far each pole piece was from the string, thereby adjusting the signal strength and tone for each. Gibson Goldtop Les Paul guitars of today are fitted with P-90s to give them the vintage sound of the original before it switched over to humbuckers which became the standard for most models of Les Paul guitars after 1958.
In 1934, the American professional audio company Electro-Voice of South Bend, Indiana, invented the first “humbucking coil” which was designed for use in microphones and loudspeakers for public events. Joseph Raymond Butts would later use this model to design pickups that got rid of the hum inherent on single-coil pickups. After successfully building a working model, he began to work with Gretsch to further the idea. At about the same time, Seth Lover of Gibson was working on the same concept but was unaware of Ray Butts similar work. Although no one is sure who actually invented the humbucking pickup first, Ray Butts was granted a U.S. patent for his design right before Seth Lover got his.
Seth Lover's PAF Humbucker pickups
The first popular commercial humbucker was Seth Lover’s PAF model (which stood for “Patent Applied For,” interestingly enough) which would be used on Gibson’s Les Paul guitars starting in 1955. Although Gibson was certainly not the first company to use humbucking pickups on guitars, the popularity of the Les Paul essentially tied the two together, along with Seth Lover as the inventor.
The reason for the need of humbuckers was the inherent flaws of the single coil pickups which had the same electromagnetic features as antennas, meaning anything close in range that produced even a slight magnetic field, such as transformers, televisions, electrical appliances and even radio signals if strong enough, would cause the pickup to take in the signal and output it as a consistent audible buzz or “hum.” Humbuckers were able to negate this by using two single coiled pickups placed next to each other but with the coils wrapped in opposite directions so that the signal from the strings would travel along the same direction. Just imagine two gears, the left going clockwise and the right going counter-clockwise. If you stick your hand in the middle of the two, they will both pull you in exactly the same as the dual coils do with magnetic voltage from the strings. Electrical interferences on the other hand are not sensitive to the magnets and only to the direction of the coil. Since the coils are going in opposite directions, the electrical interferences go opposite as well. When the two signals from each pickup are combined, the opposing electrical interference signals cancel out. This can be further explained in detail by learning about the principles of what electrical engineers call “common-mode rejection.”
Check back again Tomorrow for Part II !
That’s all the time we have left for today but comeback tomorrow when we will be discussing variations within single coil and humbucking pickups such as active versus passive and flat-pole versus staggered pole as well as several more exotic designs!
*Update* Check out part II right here!