I'll try the most basic explanation.
Of course it gets much more complicated than that but it's my most basic understanding of the different classes of amplification.
I really only know that Class A amps are usually lower wattage, inefficient (whatever that means aside from drawing more electricity from the outlet...), run hot, but sound good (right?).The output is always on driving both the positive and negative side of the signal.
Class A/B is some type of dual mode where it runs in Class A for the first few watts then switches to Class B? Now this doesn't really make any sense to me. Wouldn't the transition be audible?Not at all. Class A/B has 2 outputs where one side only passes the positive part of the signal and the other for the negative side. You also just doubled the output power. Can you hear the switch over? Um no. Some manufacturers will start in class A then switch to A/B for more power.
Then Class D... some type of switching amp, where it switches on and off? This makes no sense to me either. And why the heck did I think it was a Digital amp?The outputs are turned on and off very fast (usually in the mega hertz or way out of the audible range) and then filtered. So the output is on as much as it is turned off. But the resulting output like the input is analog (sine wave). Digital is a bunch of square wave pulses that needs to be converted to analog. With Class D the signal is analog with the power being turned on and off.
Of course it gets much more complicated than that but it's my most basic understanding of the different classes of amplification.