Class-A power amplifiers
An introduction to class-A
The two salient facts about Class-A amplifiers are that they are inefficient, and that they give the best possible distortion performance. They will never supplant Class-B amplifiers; but they will always be around.
The quiescent dissipation of the classic Class-A amplifier is equal to twice the maximum output power, making massive power outputs impractical, if only because of the discomfort engendered in the summer months. However, the nature of human hearing means that the power of an amplifier must be considerably increased to sound significantly louder. Doubling the sound pressure level (SPL) is not the same as doubling subjective loudness, the latter being measured in Sones rather than ...