when you take it to the next level vs say a very good class A amplifier , or very good class AB amps of our well known Danish companies , then myself and many others are waiting for that , look at Merrill their insane pricing ,and IMO wasted $$ on these fancy cases , a respectable look and we’ll damped chassis is more important put the $$ inside where it counts, I highly recommend using a top Furutech IEC their $75 retail being copper and gold remove Thst bottleneck judt coming in , maybe upgrading some of the filtering caps ,or putting a decent .1 poly cap on electrolytics , or Bellison regulators which are the best , man6 ways to make this a SE type quality as well as other higher quality parts look at Silmic or other smoothing caps .having spent over 20 years just in experimenting with the tonal balances of each caps and Electrolytics by far the worst in noise and filtering with poly caps , output caps , look at VH audio Odam caps ,even wire !Neotech Teflon 6-9s pure Copper wire makes a difference , or Cardas Litz wire.
@audioman58 As you can imagine we've auditioned quite a lot over the last 45 years and we've heard them make quite a difference. But that was in tube amps with little or no feedback; when you are able to run very high amounts of feedback the circuit is able to reject these very same effects; in essence they don't win you the same thing that the did if the amp were zero feedback. Even though I knew that, it was still eye opening to actually see/hear it first hand.
@mglik One does have to be careful about the Veblen Effect. As I mentioned earlier though, the reason tube power amps are on borrowed time has to do with how class D is spreading in the musical amplifier (guitar and bass) world. Since you know about a prototype amp we sent to Ron Carter, you have a better idea than most how that works. Guitar and bass amplifiers are the bread and butter of vacuum tube producers; so its not hard to imagine where this is going in the next 10 years.