Class A has always been regarded as the perfect operating mode for audio amplifiers. Many leading amplifier designers and manufacturers world wide recognise that a well designed Class A circuit has inherently lower distortion than any other design.
Class A circuit topology is one in which the total current the amplifier is capable of delivering, is kept flowing in the circuit regardless of demand. In a conventional or Class AB amplifier circuit this current flow varies when demand varies. Furthermore, as current varies, the voltage on the rails (as seen by the output stage) varies too. In a Class A circuit, current draw should be constant therefore there is an absence of the power supply modulation common in Class AB design amplifiers. Pinpoint images, tonal clarification, intertransient silence, more readily defined dynamic shadings, inner detail and authority are all inherent advantages of good Class A design.
20
