A guitar amplifier is designed to make an acoustic or electric guitar signal louder. The sound is produced through the loud speaker. The tone is modified by emphasizing or de-emphasizing certain frequencies and adding electronic effects. The guitar amplifier has a pre amplifier stage to amplify the level of the signal from the guitar and a power amplifier stage to deliver a higher current to drive the loud speaker. The pre-amplifier stage contains electronic circuits for different effects like distortion, chorus, or reverb and controls like graphic equalizer.
Guitar amplifiers have two configurations:
A. Combination (combo) amplifiers which comprise of an amplifier and 1\2\4 speakers in a wooden cabinet.
B. Stand alone amplifiers head or amp head which does not include a speaker.
Prices of guitar amplifiers vary from basic models for students at $50 or less to expensive boutique, custom made amplifiers for professional musicians costing thousands of dollars.
In the combo version of the guitar amplifiers the amplifier head contains the electronic circuitry of the pre-amp, built in effects processing and the power amplifiers .Combo amps have at least 1\4 inches input jack to plug in patch cord from the electric guitar. Other jacks may also be provided, eg: ”send and return” jack to create special effects like compression, reverb, etc, extension speaker jack, stereo RCA jack, to connect a CD player and headphone jack for the player for practice purposes.
In amp head guitar amplifiers, the amplifier head and speakers are separated and are connected by cables. Amp head also have different jacks as in combo. Guitar amplifiers are mostly made of solid state devices, though many guitarists especially in the genres of blues and rock prefer the sound of amplifiers with vacuum tubes. in the late 1990’s modeling amps have been designed which stimulate a wide variety of sounds. However many players still prefer the tube version for its versatility in sound reproduction.
A wide range of guitar amplifiers is available:
1. Traditional guitar amplifiers – clean warm sound with sometimes built in reverb and tremolo units.
2. Hard rock style guitar amplifiers users use the amplifier tone to add drive, intensity and edge to the guitar sound. Used for hard rock , metal and punk.
3. Bass amplifiers with extended bass response and tone controls tailored for bass guitars.
4. Keyboard amplifiers – very low distortion and flat frequency response.
5. Acoustic amplifiers – is designed to produce clean, transparent, acoustic sound.