switching between two amplifiers; issues of power

The excellent and more powerful Job amp should be on your list IF your new amp does not meet expectations. We have one in the studio, it is rarely powered down.

@tomic601 That's interesting... Mrdecibel convinced me to stay away from the Job, suggesting it would have similar difficulty, owing to the low impedance of my speakers, dropping down to 3.1 ohms, according to claims by one owner of Tekton Moabs. I also understand they not longer make the Job 225, and I understand this might be related to design flaws and reliability. I've heard a variety of reliability comments on the Job, and your comments come out on the positive side...

It seems the Job would have an easier time supporting LARGE LOUD bass notes, like the kind that open the live version of Styx's "Snowblind" (song 5, on the first disc), on their Caught in the Act, album. I'm actually more 'asking' if the Job amp would do better, specifically in terms of handling LOUD BASS and in managing heat at louder play. The Nuforce STA200 is wonderful, vivid, clear, particularly skilled in rendering the music and imparting a feeling of the space, but things shift a bit when  I'm asking for average delivery levels of 90+ db, with peaks in high 90's or above. Give it an hour in that territory and the heat sinks are VERY hot, maybe not burning, but very hot, and the entire chassis is also hot. I've always brought the volume level down at that point and things seem to cool well.

I want to clarify that aside from the heat, the other issue is that I want to be able to play the very biggest bass notes without difficulty. The NuForce does not play Royals by Lorde particularly well. I do not pursue this kind of music but rarely, but if I'm going to buy another amp, I think I want it to be able to handle the big stuff. That's the primary motivation, although I'm intrigued by class d. As mentioned, things are too hot in my home for tubes, during the summer. This is why I've got what some are reporting is an excellent low-cost decently powered class D amp heading this way...

A couple of caveats. I had (still have) a similar situation. I have a pair of tubed mono block amps that I use for serious listening and a SS amp which I keep as a backup or use when I just want some background music on but don't want to put hours on my tube amps. Both are connected through a Beresford switch box to my single pair of speakers. When I want to swap amps or do an A-B comparison, its simply a matter of throwing the switches on the Beresford. DO NOT CONFUSE THIS WITH A SPEAKER SELECTION SWITCH BOX. The Beresford is specifically designed for the exact purpose of swapping amps to a single speaker load. Also I believe i read somewhere that tube amps should never be left on without a load connected. This is consistent with the Beresford design the circuitry of which  includes dummy load resistors to prevent a powered on tube amp from seeing an open load. 

J.Chip

Well, mr decibel is one who’s input I trust for sure. We don’t run an hour in the high nineties for many reasons... this isn’t a lecture but watch your ears !!!! Royals is a high power density track ( give me a bit and I will post the RTA of that track on my virtual system page - I was recently using that to help a fellow audiogon member size his amplifier ( with less efficient speakers than yours )
your hour requirement drives duty cycle. In an A/B amp, you need a beefy power supply, lots of output devices and a way to get the heat out. Look under the hood on the 225 and it will indeed be lacking, so I retract my recommendation. I would point you to Van Alstine IF the class D disappoints. I will let you know when I put up the RTA photo - it is a great track for taxing a system.

Yes, my use of high nineties was for projection out of windows into my backyard. With alleged 98db speakers, I didn't think this would be a problem (for the Nuforce), but it did heat up (considerably) over the hour... 

Within the 12x14.5 room of primary listenership, Peaks are more in the high eighties, or lower, for most of my listening. I should try Royals in that context, but truth-be-told, I'm fairly tired of the song. It's more a sonic biceps flex than anything else.

Just received Trio Jeepy CD from the culture of Amazon, and the hints of the original space of recording come through. Love the distance-impression of the sax, out on the left, the chunky and springy percussion off the right, the sweet double-bass in the midst. The Nuforce is perfect for this. 

I'd be interested to learn more about how the RTA of Royals interacts with an amp. 

@tomic601 You mention, "Van Alstine IF the class D disappoints." I did a search, nothing came up that matched...