Tube Integrated Amp to Drive Floorstanding Speakers?


forgive me, but i'm a relative newbie to audiophile concepts.  i am looking to build a 2 channel system for music that i can grow with.  currently i have a VPI Prime, Soundsmith MKIII cart.   I'm using a vintage kenwood KA-9100 driving Elac Uni F bookshelf speakers for my office.   

in the future, i plan on a listening room of 15x20, give or take.    I am intrigued by integrated tube amps - looking at all sorts, including PrimaLuna, VPI 299d, etc.   but these amps have lower WPC outputs.   I'd like to grow into a floorstanding set, something like the Monitor Gold, KEF R-series or PBS Imagine T3 range.    My tastes range from Classical to Classic Rock.   i do not blast music by any means.    Is an integrated tube amp (35-40 wpc) sufficient and will it leave room to grow?   ideally i'd like a home threater bypass should i decide to add TV that into the mix
mjb87062017
sounderm- you had me a 'poo-poo' !!. thank you, that was exactly the analysis i was looking for.  I have read great things about the KT120s.  thanks again, enjoy your system.  
@oblgny , I would scratch Audio Breakthroughs from my list. It is a shadow of its' former self.
@mjb, Unless your are out on the twin forks, getting to Manhattan isn't exactly the hardest thing to do, especially if you want to audition before you buy.
B
I've had very good dealings with Audio Breakthroughs which is why I mentioned them - always a pleasure in my book. 


mjb, one other thing I’d say. I have used both the KT120s and the EL34s in my PL HP. After using them for a while, I moved back to the EL34s from the KT120s. The reason is that I notice a certain midrange "glare" that's most noticable on vocals with the KT120s that I don’t hear with the EL34s. Yes, the bass is better, and extension is better with the KT120s. But, I can’t seem to get past the midrange glare. The EL34s don’t have this at all. The overall sound is a bit smoother and more pleasant.

So, that’s why I plan to move to the KT150s. From what I’ve read, they seem to be closer to the EL34 sound balance with the KT120 sparkle and punch, but without that glare. We will see, soon as I scrape my pennies together.

One other thing I forgot to mention. My listening area is about 13x13. But one wall is open to a large room, approx 30x25. So, it’s sort of an L-shaped room, with the side area set up for more critical listening. But, in the larger room, it’s plenty loud, very clear, and overall plenty of power for the space. Sounds great, and everyone loves the PL and B&W match.
I can vouch for the Prima Luna Dialogue HP Integrated. It easily drives larger floorstanding speakers (like Proac D48R) that many tube amps will simply not get a grip on. I was impressed by the bass control and speed which I was not expecting from such a modestly priced unit. Check one out. You might well be pleasantly surprised as I was.