Class A means very little - a high bias A/B can sound just as good. Most rate their “Class A” rating into a 8 ohm load so if a amp is rated at 50W Class A into 8 ohms - that same amp will only produce 25W class A into a 4 Ohm load.
Look into thd Yamaha AS series integrated amps - beyond excellent sounding units.
Nelson Pass wrote an excellent paper on Class A amps you can read it on the Pass DIY site
good Listening
Peter