Amplification: what are the biggest advances of the last 40 years?


As an audiophile most of my adult life but without any engineering expertise, I wonder how amplification has advanced since I started in this hobby as a high school student in the eighties?

Specifically, what has advanced the state of the art and what, specifically, make newer products sound "better" than older ones?

Is it that circuit design has advanced so much?  Or is the bigger difference parts quality and the technology leading to these better parts?

And please, none of the banal "it all matters" comments.  What I'm asking: which of the above matters the most?


bobbydd
@imhififan : Especially Nelson Pass once said personally…that it’s actually the market itself that „requires“ some so called updates in his amps. He said that when asked why there is technically no difference between his X600 monos and the successor X600.5‘s …apart from a slightly different front plate. He said it winkingly … as he actually nailed the design of his monos already with the X600! The rest you can call MARKETING ;)
I think that other than refinements in circuits the biggest improvement is the GaN transistor and the new amps implementing them.

No Class D. Overrated crap. Give me some Class A. Plinius, Pass, gets the job done. 


 biggest improvement is the GaN transistor and the new amps implementing them.


Only if used to it's fullest, as Technics did in their SE-R1 (maybe in their new SU-R100) with 3 x higher switching frequency (1.5mhz) and 3 x higher output filter for it, so this sort of 10khz square wave oscillation (upper shot) doesn't come of the speaker outputs (gets reduced by 3 x).
Lower shot has Stereophile special external test gear filtering, so it doesn't look bad for the magazine shots to the public.
https://ibb.co/N2HBQH4

Cheers George
Amplification is a solved problem.   Class D is probably the biggest innovation.  These days, just buy the amp you like the looks of that you can afford and you will be fine.   The biggest innovation in audiophile world has been the amazing ability to cram dollars into amplifier designs.