Class A SS vs. Class A/B SS

I am looking for a new amp/integrated for my Adagios (89db), I currently run KT88/6sn7 tube monos (50w), i want to buy a SS setup for when I want to just fire up an play (my vintage tubes take a while to warm up), I am torn between a high quality A/B design (eg. Bryston 4bsst, Pass, even Class D Bel Canto, W4S or MF integrated) or a true Class A amp like the 30w Pass 30.5 or a Class A Luxman or Accuphase etc. I am kinda leaning toward integrated for the convenience. I listen to primarily vinyl. Please help I know much less wattage is required for class A but how much is enough?
I ran Monarchy SM-70 monoblocks for a number of years with great success. They deliver Class A sweetness in spades and drove with authority every speaker I threw at them. They were a bit noisy but the newer Mk IIs are supposed to be significantly quieter. Definitely worth a listen.

I own the INT-30A, have not heard the INT-150. Mark at Reno HiFi strongly recommended the 30A for my comparatively quiet listening habits, and I've been very pleased. But I assume Pass makes both models for a reason, and each involves a distinct set of compromises (see the detailed review of each in 6moons). In particular, it wouldn't surprise me if people with large rooms, thirsty speakers, and high volumes had "power issues" with the 30A. Here's a little test I did (from another thread):

"Just compared my new INT-30A (basically the 30.5 boxed with a minimalist pre) against the INT-30A pre-section running an Odyssey Dual Mono (180wpc) as amp. Speakers are 92/4, room 14x20 in an open plan. Obviously, "synergy" favors the INT running as intended, and it did sound conspicuously better than the combo with the Odyssey: more air, richness, texture, detail, etc. *Except* that the combo had conspicuously more authority on the lows. I listen to mostly "small" music at lower volumes, and I'm sold on the sweetness of the Pass, but I concluded that those who say many listeners will want more power than the 30 are likely on to something."

At present I'm very happy with my decision, but I doubt the difference between the 150 and 30A (or the corresponding separates) is a coin flip.

Enjoying the simplicity of an integrated, btw.

If you are going to go with Pass Labs, I would definately go with their Class A amps, like the newer 30.5 vs. their Class A-A/B amps.

My experience with Pass amps is that they are great as long as you stay in class A, but once you cross over into A/B, you suffer.

I would not rule out the Pass Labs Aleph amps (which operate only in class A) as well. The Alephs are SET based solid state amps. If the power they provide will be sufficient for your needs, you may very well find them quite enjoyable.

Also, I think a Mark Levinson amp may deliver both a sound you may like and enjoy. Even an older 23.5 or a 27/27.5 (which I believe is only 50 wpc) would also be considerations - of course used.

Assuming your 50 watt KT88s is plenty for the Adagios, I think you have some good options.

Finally, my experience is not that watts are watts. Oh, if it were only so easy.
Though not yet set up to play -- that applies to the whole "new" system I have been assembling from the ground up -- I have a pair of the Adagios here. My expected-to-be #1 amp currently in residence is a Cy Brenneman 15+ watt SEPentode-follower (KT-88... KT-120?) Cavalier Plus. Adagio designer Robert Lee assured me that I would have sufficient power for my personal requirements -- ecclectic tastes, infrequent LOUD sessions.

Everything being "new", I wanted options, including higher power tube (got 'em) and solid state. FWIW (still expecting to be first and foremost in the tube camp -- though not dogmatically), I bought a Pass Aleph 30 and a new Illinois Rawson (sort of FW F5 on steroids) from Tim here on
Audiogon. Hard to beat this combo for the price, I expect. I do not anticipate being short of steam.

Also note that Paul Speltz's Zero autoformers can be used to deliver more CURRENT grunt from these amps -- yes, you can get more EFFECTIVE wattage out of these into some loudspeakers via this route. Not a "free lunch" -- but it may seem that way in some cases.
@Armstrod is correct...the Monarchy Monoblocks sound wonderful. I heard them and have been contemplating a pair of their balanced mono blocks. The SM70 Pro is 40% off, making it less than $600 per mono block. That is making it tough for me not to buy!