A "'valve amplifier "'or "'tube amplifier "'is a type of electronic amplifier that uses vacuum tubes to increase the amplitude or power of a solid state amplifiers during the 1960s and 1970s.
32.
Valve amplifiers are perceived by musicians and fans to have a " warmer " tone than those of transistor amps, particularly when overdriven ( turned up to the level that the amplifier starts to " lead " tone ) with a foot-operated switch.
33.
It was realized that such devices could be used in the detection and counting of Alpha particles in the nuclear disintegration experiments then being undertaken by Rutherford, who encouraged him to devote his attention to the construction of a reliable valve amplifier and methods of registering and counting particles.
34.
During this period, the Selmer range of Treble & Bass 50 & 100 valve amplifiers appeared to be stylistic relics from pre-1959 and the decision was made to move the manufacturing facility to a disused brush and coconut matting works dating from 1914, based in rural Essex.
35.
The development of AC-operated domestic radio receivers in the late 1920s created a demand for large-capacitance ( for the time ) and high-voltage capacitors for the valve amplifier technique, typically at least 4 microfarads and rated at around 500 volts DC . Waxed paper and oiled silk film capacitors were available, but devices with that order of capacitance and voltage rating were bulky and prohibitively expensive.
