Then your answer if you insist on class A is a Quad current dumping amp. That is Peter Walkers brilliant invention.
The concept, is a class A/B amp, that actually does not have to be outstanding. This is the dumper. Then there is a very good class A amp that feeds a feed forward error correction. This gives pure class A performance. It can be shown mathematically and in practice that the performance is entirely the spec. of the class A amp.
These amps run very cool.
3 KW of class A audio power that powers my studio/AV room. That is a bank of seven Quad 909 power amps.