A tube amplifier, often referred to as a valve amplifier or simply an amp, is an electronic amplifier that uses vacuum tubes to amplify a signal. Vacuum tubes are electronic devices that use the flow of electrons in a vacuum to amplify or control signals. Tube amplifiers are often used in audio applications, such as guitar amplifiers and hi-fi systems, because they produce a warm, rich sound that is often preferred by musicians and audiophiles.
Tube amplifiers were the first type of electronic amplifier, and they were used in a wide variety of applications, including radio, television, and telephony. However, they were largely replaced by solid-state amplifiers in the 1960s and 1970s, which are smaller, more efficient, and more reliable. Despite this, tube amplifiers remain popular in some applications, such as guitar amplifiers and hi-fi systems, where their unique sound is valued.