Guitar Amps


Electric guitars make very little noise on their own. In order for electric guitars to reach their full potential, they need to be connected to a guitar amplifier or other amplification device. Most commonly, guitar amps are free standing objects that look vaguely like a large speaker. The details of how amps work, however, are a little bit more complex than the mechanics of a basic speaker.

There are actually two different set ups of amps. Combination amps combine the amplifier head and the speaker or speakers into a single device. Separate amps consist only of the amplifier head, and require an external speaker to be connected to the amplifier head in order for it to produce sound. For the ease of discussion, the following explanation better describes the workings of a combination amp, though the workings are essentially the same for either type. Generally speaking, combination amps are the type of amp that an individual guitarist is most likely to purchase and use at home, while the more elaborate separate amp is more often used for live performances.

Amps require electrical power to drive them, with modern amps receiving their power from a standard grounded outlet. The circuitry of an amplifier allows it to recognize the signal transmitted by an electric guitar, and the combination of this information with the electrical power allows the amplifier to produce an amplified version of the signal. This amplified version is then transmitted to the speaker, which actually produces the amplified sound.

Earlier guitar amps relied on the use of vacuum tubes to do the work of amplifying the electric guitar's signal. The major problems with this type of amp are that they are heavy devices and that the vacuum tubes need to be replaced and the amp recalibrated every year or two, if the amp is used frequently. Many blues and rock guitarists are willing to overlook these problems because of the quality of sound produced by vacuum tube amps.

More modern guitar amps use solid state technology, which means that the signal from the electric guitar is transmitted through conductive metals rather than through the empty spaces within vacuum tubes. Solid state amps weigh less than their vacuum tubed counterparts, and are also somewhat easier to repair and less expensive. The ease of repair is debatable, because generally only an experienced technician will be able to repair a solid state amp, while most people will be capable of replacing a vacuum tube on a vacuum tube amp. There are also some modern amps which combine both vacuum tubes and solid state technology.

Since the 1990s, some companies have been manufacturing modeling amps, which are amplifiers that reproduce the sound of classic vacuum tube amps digitally. Guitarists are somewhat torn on the usefulness of modeling amps, as they do a nearly perfect job of reproducing the sound of older amps, but there are slight, almost undetectable, differences, which experienced guitar players may be able to recognize.

Aside from being used to amplify the sound produced by an electric guitar, amps can also be used to create feedback loops. While most people want to avoid feedback from microphones, guitar players can use the feedback produced by an amp to keep the strings of their guitar vibrating indefinitely, which means that a note or chord can be played indefinitely with only minimal effort by the guitarist.

This is just one form of sound distortion than an amp can provide; most modern amps will include some distortion controls that can be used to raise or lower the level of sound distortion. In the 1960s, however, guitarists experimented heavily with what they could do with their amps to achieve various levels of distortion. Dave Davies, guitarist for The Kinks, even plugged the output from one amp into the input of a second amp to create heavy distortion for his guitar sound. Needless to say, this had the potential to be very hazardous as it was likely to overload the second amp.

Many guitar manufacturers also make guitar amps, but there are some companies that devote their attention solely to the production of amps. Probably one of the best known amp manufacturers is Marshall Amplification, a British company which has been making amps since the 1960s. Marshall primarily produces vacuum tube, or valve, amps, though they have branched out to manufacturing lower priced solid state and hybrid amps. The Marshall Stack, which consists of an amplifier head atop two speaker cabinets, each of which contains four twelve inch speakers, is nearly iconic in live rock performances.

While electric guitars require external amplification, some acoustic guitars are outfitted with the electronic devices necessary to hook them into an amp. Generally speaking, though, it is the electric guitar player who will have need of an amp. The options available for guitar amps range widely, depending both on the purpose the amp will serve and technological preferences. Most electric guitarists will be able to find an amp that works for their need for amplification.