Pickups
Guitar pickups consists of a magnet usually made of alnico with copper wire the width of a human hair wrapped around them thousands of times. The magnet produces a magnetic field around itself. Guitar strings are made of steel so as they are picked they interact with the magnetic field. The vibrating strings energy is converted into Alternating Current and its this electrical pulse that is sent down the guitars lead and into the amp where it’s is amplified and sent to the speaker becoming the note that is heard as the end product.
Single Coils
The single coil pickup was designed by Leo Fender and are the pickup types found on a Stratocaster and many other guitars. The single coil consists of 6 magnetic poles each wrapped with copper wire thousands of turns. There are 6 individual pole pieces instead of a bar magnet as this method allows each ‘pole’ to be adjusted in height individually therefore equalising the volume for all 6 pickups. The single coil pickup sounds clear and they have an emphasis on the treble frequencies. Originally one drawback with the single coil pickup was the amount of interference or background noise the single coil produced when used with an amplifier dialled up with high gain (distortion/overdrive).
Humbuckers
As mentioned a disadvantage of single coil pickup was the amount of unwanted noise or ‘hum’ it produced. This problem was resolved by Seth Lover whilst working for Gibson in 1955. He designed the Humbucker to have two coils which are wired in series so the electric current flows through one and then through the other but they are out of phase of one another. This cancels out any noises or ‘hum’ the single coil pickups suffer with hence the name ‘Humbucker’. The humbucker has less of a response to higher frequencies than the single coil but has a punchier fatter sound more suited to power chords and rock music.
Noiseless Single Coils
As already mentioned, the main problem of single coil pickups is they tend to produce unwanted noises. The hum produced in single coils tend to be caused by the magnetic fields of electrical equipment. They also suffer buzz which sounds a little like static and is actually radio frequency noise. Kinman pickups were one of the early pioneers in noiseless single coil technology patenting their first designs in the mid 1990’s. Other companies that have developed these type of pickups include Fender, DiMarzio and Seymour Duncan.
Lipstick Pickups
The lipstick pickup is a type of single coil pickup. The name is derived due to the pickups being originally manufactured using lipstick tubes. The electronics of the pickups are incased in a chrome metal tube and were first designed by Danelectro. They have a sound which can be describes as ‘jangly’ and are often used in ‘Surf’ and ‘Rockabilly’ music.
Uncovered Humbuckers
These are basically humbuckers without the chrome or nickel covers. Some people believe there are no difference between the tone produced by uncovered and covered pickups. Other people are of the opinion that on the plus side covered pickups may reduce hum yet also reduce the brightness of the pickups. All of this is a little subjective with the difference being fairly minimal.
Zebra Humbuckers
Zebra pickups obviously get their name from the combination of the black and cream plastic. The origin of these pickups date back to 1959 and 1960. Gibson had a shortage of black plastic used in the production of their pickups but as the pickups were covered by a nickel plate this didn’t effect the overall look of the guitar. Some guitarists started to take a look under the cover to see whether they had the standard black or Zebra pickups. Believe it or not some players were convinced that the Zebra configuration actually made the guitars sound better. Soon after pickup manufactures began making these pickups to satisfy the demand.
Active Humbuckers
Pickups are either active or passive. So far every other pickup mentioned in this guide is passive. Active pickups are pretty much the same as passive pickups but with a preamp built in which is powered by a battery. The preamp works in a similar way to an amplifiers preamp and basically adds extra tone shaping and more EQ possibilities than passive pickups can provide. Extra voltage gain in the guitar signal makes it more powerful and allows pickup manufactures to tune specific frequencies of the guitars output. This therefore makes active pickups popular with rock and metal guitar players.
P-90 Pickups
The P90 pickup was designed by Gibson way back in 1946. There are 3 different types of these pickups – The P90 with a humbucker type casing is slightly smaller than a standard humbucker in width but bigger than a single coil. The P90 dog ear has extensions on either side of the pickup which resembles dog ears. The last version is the P90 soap bar which is shown below. This version, as I’m sure you can guess gets its name due to its obvious resemblance to a bar of soap. P90’s are actually single coil pickups but use bar magnets in the same way as humbuckers as opposed to the pole magnets found in single coils. This results in a pickup that sounds like a single coil in some aspects but also has sounds associated with a humbucker due to the similar magnet layout.
Single Coil Size Humbucker
For guitarists wanting to ‘beef’ up the sound of their single coil equipped guitars they have the option of dropping in a humbucker into a single coil size pickup cavity. These types of pickups are called stacked humbuckers. The coils in these pickups, as the name suggests are stacked vertically rather than side by side which is how standard humbuckers are configured. Another type of pickup is the rail humbucker. The coil windings of these pickups are wound around two pole pieces which look like rails, hence the name. The Stratocaster shown below is retro fitted with a Seymour Duncan Hot Rail humbucker.
Narrowfield Pickups
Narrowfield pickups are a PRS design and have shared characteristics as their full size 57/08 humbucker pickup. The narrowfield was designed due to PRS’ desire to create a pickup that doesn’t produce any hum and has characteristics of humbuckers, single coils and P90’s. This creates a very versatile pickup.
Coil Split
Guitars that have humbuckers can also be fitted with coil splits. A coil split is when one of the two coils of the humbucker is bypassed. It is subjective whether a coil split humbucker sounds the same as a real single coil but effectively this is what it has become. The coil splitting is achieved with an extra switch on the guitar or via a push pull volume or tone control. Some guitars can be bought with coil splits but any guitar with a humbucker can be retro fitted to do this as well. Coil Splits are frequently wrongly called coil taps. A coil tap is when the pickup can be ‘tapped into’ at a lower number of windings than the pickup might have. For example a pickup may have 10,000 windings of wire in total but the ‘coil tap’ is made at 8000 windings. This produces lower output of the pickup therefore changing the sound produced.
Piezo Pickups
Piezo pickups work differently to magnetic pickups as they don’t use the interaction of a string and magnetic field to create the sound. Instead the pressure of a string vibrating is measured and this is what causes an electric current. The vibrations of the string and the tonal qualities of the wood and the bridge all come together to produce an accurate representation of how the guitar actually sounds. This is one reason why electric guitars sound similar to acoustic guitars which also use piezo pickups. Unlike magnetic pickups which are clearly visible underneath the strings piezo pickups aren’t. This is because they are actually contained within the guitars bridge. A really nice feature of electric guitars fitted with magnetic and piezo pickups are the ability to select which pickup type can be used. The two pickups can also be blended together. Therefore, an electric guitar fitted with piezo’s can increase the versatility of the guitar with the increased amount of sounds which are available to a guitarist.