What amps should I audition?

If we are just throwing ideas hoping one will stick... I wish I had the chance to try the Carver Crimson 350 Raven monoblocks. They are the only amps I would like to try besides just buying a Bryston Cubed something. Pair of 7B3s or a 14B3

Sorry I upset you tiong. I am even sorry I was so cruel about MAC gear. I should say I find MAC transistor gear under-performing in a price to benefit way. Older MAC tube gear is not part of my general rant against MAC gear. I get upset when folks say Bryston is sterile sounding. Well yeah, maybe 30 years ago. Not today.               
But I do not say I am going to 'shoot myself in the foot' over it. Usually just saying, that is a mis -statement, I find blah blah blah to be true, not blah blah blahbla. See, easy. I am only cruel sometimes. Usually I am very nice... in a cruel person's way of being nice...

I would discuss what is needed to get that home audition. Few dealers (really no dealers) will offer a no cost home audition to a stranger. The dealer has a brand new item, used when it is returned. They assume you will return it. What is in it for them? nothing. All it is doing is costing them.
In order to get a home audition I had known my dealer for 33 years,and had spent $40,000 previously there. He offered a Marantz SA-10 for me to audition cold (I did not ask) for five days, no strings.
So the only sort of deal you could go for is like Audio Advisor accepts returns. The one problem there, is they WILL cut you off if you return a big item. Like that $12,000 amp is the only thing you bought, and returned it? Never again. On the other hand, a few companies. Like the current Carver tube offers, offer money back guarantee, I think so does PS Audio?
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Anyway, I ask If you LIKED the Bryston, why do not want something else? The ’grass’ is NOT greener in unknown products. (Particularly MAC gear. MAC gear SUCKS! soundwise.. Jeez.) Just buy a used Bryston 14B3, pair of 7B3’s, or a pair of used 28B3 and stick to your Niagra preamp idea.
I LIKED the sound of my Magnepan 3.6, so KNOWING THAT I went to 20.7s I am happy. I own a 4B-SST² amp. When I actually have some money again, I will go WITH WHAT I LIKE which will be a Bryston pair of 7B3 or a 14B3.. maybe used, maybe new. Sure I can think what about a different amp. Pass? Maybe a tube Carver? but knowing it is a crapshoot.. I will stick to the Bryston. (which sounds great)
I like to try preamps. so there I do play around. Last try was a Conrad Johnson ACT2. (I am disappointed that it was not way way better than my other preamps.. it is good, just not spectacular) I still use my Bryston BP26. The biggest problem for me in tubes is I play music 8 to 10 hours every day. Wearing out tubes too fast. I WOULD go for a Audio Research preamp. Ref 5SE or 6, except for the tube life. I would have to buy new tubes every eight to ten months. Not interested!)
Back to your needs. I would like to know more WHY, if you liked the Bryston/Nagra. are you not going there? The Bryston used is EASY. (as long as you get the dealer receipt for warranty) The Nagra.. Probably have to save up to buy new. or have the money and search the ads for a long time.. Here elsewhere. every day. (the problem is, high demand stuff is sold the same day. Stuff no one whats you can see endlessly day after day. (A nice phono box I was thinking about the same day it posted? IF I would have clicked buy the moment I first saw it. I might have it. Since I waited ten minutes, dawdling . I lost it.)
I have the feeling you are waffling. You want the best, you are worried, can "X" be better than what I heard as great? MY advice from FIFTY FOUR YEARS of buying audio stuff is BUY what you heard and liked. There IS NO magic other pile. yeah you can TRY.. Spending megabucks and being disappointed AGAIN... THAT is the audiophile mantra. Sadly it is very hard to find anyone willing to loan equipment. The money is just not in it, for them, at all. The only real way is buy used, try it, sell it for what you paid. Plenty of folks do that. They are never satisfied. Since the grass really is never greener.. anywhere.

Just a funny mention about Class A and Pass. Read somewhere fellow bought four Pass amps, Big class A amps. He was letting the break in, so he left them on for the whole time... Until he got the electric bill and it was $900 more than usual. (The heat had to be sucked away by the air conditioning, besides the amps)
Suffice to say he shut them off. I do not know if he kept them.
In passing, My little Forte’ 4a amp raised my electric bill ten bucks a month to be left on 24/7. My current stuff adds $30 month to my bill. Left on 24/7 and no class A amp here.

I can say in day to day use any electronics that run hot get annoying for that reason soon enough. A hot Summer day, Air conditioning going full blast and you want to listen to some music. but DON'T because the amps or whatever are blazing hot to run??? Then the folks who own a second amp for Summer use? Because the favorite is a furnace? Reason enough to avoid Class A amplifiers and big tube amps.

Why address the shielded question to me?
As a ’wild guess’ the circuitry in the Bryston amps is far enough away that there is no need for a shield. (plus Bryston uses a separate toroid for each channel, they are stacked inside the case) Thus each transformer is smaller., with a smaller field. ?Plus how much is marketing vs actual improvement in the sound. Like the 1970’s specs with tons of feedback to make SPECS look good. IS the shielding for a reason? (Maybe some designs placed critical components TOO CLOSE, and wanted to keep them there, so they added a shield?) all sorts of possible reasons either way. IMO this is a THEORY question, One where there is not actual answer anyone can work with, just plays off folks needing excuses instead of actual listening.            
And finally if a shielded transformer made ANY difference to the performance of a Bryston amp.. There would be at least several posts somewhere (I would have seen and read) discussing ADDING shielding and how it improves the sound. Since there are NONE.. I can say it does not add anything of value to the sound of a Bryston amp. Because somewhere, someone would be doing it ... if it mattered.)

On the point of spending on peripherals, Yes you need IC and AC upgrades. But not neccessarily the same time. My efforts have been to buy the best I can afford, then the next phase of spending after I paid off the junk I just bought, is the accessories to top notch. Then back to the most important item.. upgrade..                      
So eight years ago I bought new amp, preamp, speakers. Over the next few years I bought power conditioners, power cords, IC.. Then this year I upgraded the speakers, and a DAC for the main items. And added in some AC duplex.           
So my new way better speakers had the stuff they needed to sound good right off. And I know as I upgrade other bits, the whole will get better too.

If the op waits long enough.. and enough people give their suggestion, nearly every amp made will get a recommendation!

That McIntosh 462 looks pretty.
The op should do some reading up on the current not so great state of MAC service and repair. Also the number of current new from the box issues with MAC gear. The word is (from long time MAC users) is MAC is NOT quite the company it used to be. New corporate owners, new problems make MAC a not the best choice, unless you just have to have those blue meters. All this bad mouthing? Well I am just writing the same stuff written over at Audio Affectionado. (Big McIntosh lovers) t is true, bad news gets a hundred times the volume of good news. I am not trying to ’harm’ MAC. just stating what MAC folks are stating in other forums.Some of the same is being said about Audio Research, but not as bad. The main issue there seems to be older gear is not getting repaired by ARC. They are washing their hands, suggest the owners, buy new ARC gear.(ARC never would have done that back in the day...)