Class-XD ™ : crossover displacement technology
Class-B linearity can of course be very good. The Blameless ampliﬁ er design methodology, especially in its Load-Invariant form, yields less than 0.001% THD at 1 kHz. The limitation is that a Class-B ampliﬁ er inherently generates crossover distortion, and most inconveniently does so at
the zero-crossing, so it is always present no matter how low the signal amplitude. At one unique setting of quiescent conditions the distortion produced is at a minimum, and this characterizes optimal Class-B, but at no value can it be made to disappear. It is inherent in the classical Class-B operation of a pair of output transistors.