If a kid were to ask me, “Where does water come from?” I’d reply, “The faucet” without a second thought. So when I got the question, “What is a pickup?” I was temped to write that it’s a kind of a truck.  

But my new year’s resolution was to be less of a jerk, so… 

Pickups are used to amplify your guitar by converting the strings vibration into an electrical signal that is then sent to a preamp (where modifications can be made, such as changing the tone, adding reverb, etc.) and then sent to the amp (to amplify the sound, of course) and which is then reproduced by the speaker. Often the preamp, amp and speaker are contained in one enclosure, what is typically called my musicians as an amp.

There are pickups for both electric and acoustic guitars. Acoustic guitars without pickups in them can be retro-fitted with a pickup that performs as well or better than those installed at the factory.

For electric guitars, the pickups are made of magnets with wire coils around them, or a magnet with threaded pole pieces attached to it and a coil of wire around these pieces. Generally, you don’t see the coils for the pickups as they are usually covered with either plastic or metal that is plated with chrome or gold to match the guitars other metal parts.

On some guitars, the pickups are larger than others generally due to their hum canceling design: they have two coils side by side instead of one (hence they are approximately twice as big).  Pickups that use the threaded pole piece design allows you to adjust the height of each piece (usually one screw for each string, but sometimes two) to get a balanced volume for each string.

The magnet and coils work together to create a magnetic field. When a string is strummed or plucked it interrupts the magnetic field and causes the pickup to create a corresponding electrical impulse, an electric signal, which is sent to the amp.

On acoustic guitars there are both magnetic pickups (usually mounted in the round soundhole of the guitar) and piezo pickups.   Most acoustic guitars that have a pickup or had a pickup added to them usually have one type or the other, but rarely both.

The piezo works in a different way than a magnetic pickup, but accomplishes the same feat: converting a strings vibration into an electric signal.  But a piezo does so by sensing changes in pressure. This requires direct contact with something that vibrates. On acoustic guitars this is generally not the string itself, but the saddle, bridge plate or soundboard of the guitar.

On an acoustic guitar, the strings produce very little sound. Most of the sound we hear is created by the top, or soundboard, of the guitar vibrating. Of course, this vibration is set in motion my plucking or strumming the strings. The back and sides of the guitar are used to project the sound forward. The piezo captures the pressure of these vibrating parts to amplify.

The cool thing about piezo pickups is that some are made to be installed under the saddle of the guitar and others are designed to be installed inside the guitar. So, an acoustic guitar can “become electric” without changing the appearance of the instrument. The piezo pickup, while not sounding wholly acoustic, tends to have more acoustic-like properties to them than magnetic pickups, making them the preferred choice of the majority of acoustic guitarists.

Both electric and acoustic guitar pickups can be purchased at any well equipped music store, but should be installed by an experienced guitar technician.   Not only can they can help you figure out what pickup will work best for you, they help you choose which will fit your guitar and accent your style of music. Plus, they’ll also set them up for optimum performance.

Jake Kelly is a man on the constant search for enlightenment, if anyone finds it let him know so he can get some. For more of this hombre’s ramblings and the rest of L2P check out L2Pbandspace and L2Pnet.com.


Originally posted 2010-08-03 21:46:27.