Class A Power in A/B amplifiers?

If the amp has feedback, you’ll probably not be able to tell anything about class A or AB.

@georgehifi seemed to have ignored the point🤦‍♂️

NO! this is bad information and definitely not correct
I have built many Class-A’s (even a massive water cooled one), I and friends could tell if they were in low bias or high bias, with feedback applied, using global or local, and using matched complimentary outputs.
And if you don’t believe me ask Nelson Pass one of the foremost Guru’s of Class-A amplification that neither of you could hold a candle to, he’ll set both of you straight.

Coda is a very old school Company Threshold Nelson Pass - 
his engineers when Nelson decided to go Solo became Coda
they  offer 3 power variants like the excellent CSIB integrated amp 
the preamp is in pure classA ,Mosfet,and FET   the separate Amplifier section 
the first 18 watts are in pure class-A ,then 150,300,600WPC,2 other power choices the higher in power the lower in pure classA,
with largest potted low noise power supply I have seen at under $15k a 3kva transformer and over 120 amps ,that’s enormous power- control on demand and 40 matched Bipolar resistors on the outputs

If referring to vacuum tubes a SET amplifier I believe is around 9 watts Max 
In a 300 B amp amplifier ,you can get 18 watts in a class A parallel circuit 
from my experience from my Tube. Expert  friend Radu.