Use of class A allows achieve low distortion with less feedback applied. That is the main advantage. Main problem is the heat: at full power amplifier will convert into heat 3 times more energy than it sends to speakers. At zero output power energy that is not sent to speaker is converted into heat too.
What are the advantages to a Class A amp & what are the trade offs?
I've never had a class a amp but am considering one now. So what am I getting myself into?