Guitars Republic

Guitar amplifiers background and history

A guitar amplifier (or amp) is an electronic device or system that strengthens the weak electrical signal from a pickup on an electric guitar, bass guitar, or acoustic guitar so that it can produce sound through one or more loudspeakers, which are typically housed in a wooden cabinet. Guitarists may also use external effects pedals to alter the sound of their tone before the signal reaches the amplifier.

History

In the 1920s, it was very hard for a musician playing a pickup-equipped guitar to find an amplifier and speaker to make their instrument louder as the only speakers that could be bought were “radio horns of limited frequency range and low acoustic output”. The cone speaker, widely used in 2000s-era amp cabinets, was not widely offered for sale until the 1930s and beyond. The first amplifiers and speakers could only be powered with large batteries, which made them heavy and hard to carry around. When engineers developed the first AC mains-powered amplifiers, they were soon used to make musical instruments louder.

Various types of tone stages may affect the guitar signal:

• Settings on the guitar itself (passive tone controls, active equalizer circuits in built-in preamps, pickup selector switch position, etc.)
• Devices between the guitar and the preamp stage, such as a wah-wah pedal or other effects units, such as chorus or reverb.
• Between the preamp and power stages (an effects loop or some dedicated amplifier tone circuits)
• Between multiple stacked preamp stages (also called “gain stages”)
• In feedback loops from a post-preamp signal to an earlier pre-preamp signal (as in the case of presence modifier circuits)

A guitar amplifier may be a standalone wood or metal cabinet that contains only the power amplifier (and preamplifier) circuits, requiring the use of a separate speaker cabinet–or it may be a “combo” amplifier, which contains both the amplifier and one or more speakers in a wooden cabinet. There is a wide range of sizes and power ratings for guitar amplifiers, from small, lightweight “practice amplifiers” with a single 6″ speaker and a 10 watt amp to heavy combo amps with four 10” or four 12″ speakers and a powerful 100 watt amplifier, which are loud enough to use in a nightclub or bar performance.

Here are some of the guitar amps available on Amazon.