Folks, just so you know, one reason there is class AB is so that there will be no crossover distortion, as opposed to class B where this is a problem (and usually class B amps are not intended for hifi operation on this account). The amp is biased just enough so that it has an operating point in the A region (at idle) so crossover distortion due to cutoff of the output devices is simply not possible. Whether you're class A to 1 watt or full power isn't going to make any difference insofar as crossover distortion is concerned.
However you do get better distortion cancellation when the amp is class A to full power and hopefully the output devices are being operated in their most linear region.
The reason to do this is that most solid state amps made in the last 70 years don't run enough feedback to really do the job that needs to be done, so to help the amp make less distortion to begin with its set up to run class A. Put another way this reduces distortion when the amp is running open loop; thus the feedback has less work to do cleaning things up.
However you do get better distortion cancellation when the amp is class A to full power and hopefully the output devices are being operated in their most linear region.
The reason to do this is that most solid state amps made in the last 70 years don't run enough feedback to really do the job that needs to be done, so to help the amp make less distortion to begin with its set up to run class A. Put another way this reduces distortion when the amp is running open loop; thus the feedback has less work to do cleaning things up.