White paper
Summary
Crossover displacement aims to provide a genuine way to affect an elegant compromise between
the superior linearity of Class A and the efficiency of Class B giving the lowest distortion possible
without implementing pure Class A operation. This compromise gives genuine measureable and
above all perceivable improvements in sound quality, and can give better sound quality than
conventional Class AB. Class XD is patent pending Cambridge Audio technology and is unique to
us.
The advantages:
•
Class XD pushes crossover distortion away from the central point where the amplifier output
spends most of its time
•
Below the transition point the amplifier actually runs in pure Class A with no crossover
artifacts at all
•
Above the transition point the amplifier moves into an optimized Class B with still lower
distortion than is possible with Class AB
•
Much lower heat than Class A, although more than conventional Class AB
References
1] Self, D
"Distortion in Power Amplifiers"
Electronics World
, Aug93-Mar94. (The Blameless
power amplifier concept)
2] Self, D
"Load-Invariant Audio Power"
Electronics World
, Jan 1997, p16.
3] Self, D
"Trimodal Audio Power"
Electronics World
, June, July 1995.
4] Self, D
"Audio Power Amplifier Design Handbook" Newnes 1996. ISBN 0-7506-2788-3.
p276.
