Class A or Class D solid-state amplifiers (modern designs)

A - Alive, Awesome, Amazing, 
 

D - Dreary, Drab, Dull

easy choice.

@petaluman As you might expect I have read Nelson's article before.

He addresses the issue of poles in the amplifier caused by adding more stages of gain and how that adversely affects the use of feedback. I addressed that issue in my first post to this thread.

A class D amp only has one stage of gain FWIW. Nelson does not address the solutions class D offers to the issues described in his article.

Clearly articdeth is out of touch with how good class D has gotten in the last few years. Most recently, GaN tech is about to sweep the floor with any class under 500 watts

@atmasphere 

My comment was about amp history.  I don't know when the cascode amp paper was written, but the Threshold CAS-1 & CAS-2 amps date from the early 80s.  I don't know the history of class D amps, but am not surprised a paper likely written ~40 years ago about audio amplification didn't include class D.

I do have a question for you, if you don't mind my asking.  As we all get older, we're discovering that parts inside our stereos age (and worse) as well.  What have you been able to glean about the long term reliability of class D amps, what goes wrong, and what is the result?  I know it's probably a lot of the same parts, but they're being used differently.

What have you been able to glean about the long term reliability of class D amps, what goes wrong, and what is the result? 

Electrolytic caps last longer if they have a charge on them and they are not subjected to heat. WRT the other parts used, surface mount has been around for several decades and reliability seems to be at or better then the level of reliability of thru-hole parts. I expect class D amps will hold up very well.