Needed: Honest Advice on high-end amps- either mono or stereo

"Forget economic proportionality- most of us are wealthy."  

Why do you assume that?

Recently I put together a new system for my second home.  I wanted it to be as good as it could be, but without spending stupid money.  The amp chosen is a Marantz PM10, a class D integrated bought on close out at fifty percent off.  It is very good and when I compared just the amp section alone using my C-J ART 88 preamp I found it compared remarkably well to my C-J ART 27A class A amp. Now I am listening to the system in my second home daily.  I can no longer compare amps, rather I am simply listening to music on a different system in a different room, but listening to many familiar records.  There is a difference.  I miss the nuance of the better equipment.  Is the difference huge?  Of course not.  Only an audiophile would appreciate the subtle differences in sound stage depth, greater sense of liveness.  Is it worth 5x or 10x more?  To me it is.

yep @ghdprentice kind of nails it …..point, set, and match in tennis jargon

@yesiam_a_pirate : When the audio hobbyist migrates up into high-end performance with a $$$$$ / Ka-Ching entry point, a couple of paradigms stand out:

(a) That anecdotal “Rule of Fourths “ (or similar variant) governs: ergo… it’s an inverse relationship that  triggers a four-fold cash drain on your wallet to acquire that added 25% in audio performance, 

That now dovetails into the following homily. 

(b) “Price is what you pay. Value is what you get.” - Warren Buffett

The only true high end amps I've heard in recent decades are the Convergent tube amps, and yes, on a top notch system they really do make a difference.  Whether or not they're worth it I can't say, because I'd be very hard pressed to justify that much money.  Diminishing returns are in full play, but are also audible.  It is a system, and it needs to all be at a similar level to maximize the overall performance.

I'd guess I'm getting roughly 90% of the performance for a fraction of the cost with some heavily modified Dyna/VTA amps in my system, but the difference is notable when I go and hear the CATs.  If I stay away, and just listen to my rig, I'm perfectly content! 

Diminishing returns is a real thing, however every step up in quality is very rewarding and typically worth the initial investment.  Notice I said quality, not price - I've heard many expensive components which were good but not groundbreaking.  When you hear something that changes your experience it's difficult to forget about - so be careful what you listen to!! :)