Vacuum tubes (valves) were by far the dominant active electronic components in most instrument amplifier applications until the 1970s, when semiconductors (transistors) started taking over for performance and economic reasons, including heat and weight reduction, and improved reliability. When a tube amp is maintained at a high level, excellent performance and life is possible. Tubes benefit from a heater warm-up period before the application of high-tension anode voltages; this allows the tube cathodes to operate without damage and so, prolongs tube life. In general, many guitarists prefer the sound of an all-tube amplifier; the aesthetic properties of tube vs. solid-state amps, though, are a topic of debate in the guitarist community. Read More>