Pass Labs x250.8 vs tube amps


I have a beautiful system. Lumin X1 > BAT Rex 2 pre > Pass Labs x250.8> Sound Labs M545 (ESL) in a tiny room (9x 11 ft).  This system has the most glorious SQ: smooth, detailed and powerful , along with great bass. I would say this sound equals or betters any ultra high end system. HOWEVER, I have a problem. My system takes 6 hours of music playing to sound this good. I had X250.5 and I had the same issue. Leaving it on idle overnight doesn’t solve the problem. It is 15 W class A, so it generates quite a bit of heat, and yet I have to still play music. Because my room is small, I don’t crank up too much- maybe this is the problem, but the temperature doesn’t complete stabilize for 5-6 hours. The top reaches 107 deg in 2 hours, but the front plate doesn’t reach 107 until the 6 th hr when it starts to sound glorious. I have never had a tube amp and I am wondering if I can reach that thermal equilibrium and the glorious SQ faster with a tube amp? I worried about the heat generation with a tube amp in this small room, but X250.8 generates 450 W just idling. This is no worse than tube amps like Audio Research 150 Se, which I demo’d and was impressed by. BTW, I need power in the amp because of the esl speakers.
What do you all think?

128x128chungjh
Roger West, the owner of Sound Labs, thought Atmosphere MA1 (140W) was powerful enough for room 9x11. Because of lack of space, I was thinking about AudioResearch 150SE stereo. I think heat generation will be similar to X250.8 but will it reach thermoequilibrium by 1-2 hr?
Take a look at the Linear Tube Audio OTL designs.  BTW, all their amps can be bridged if you need/want to.
The dynamism of X250.8 is unparalleled. With drums in Angela Brown's band, the SMACK is incredible. As I get older, I feel like I wouldn't mind with a bit less SMACK.
@twoleftears 

I think I need at least 150W for my 86db speakers, even in my tiny room. Linear Tube only goes up to 40W? (ZOTL40?).
As @decooney indicated, the heat is not my biggest issue. It is the time to warm up. My logic is that tube amps will reach the optimum temperature more quickly than Pass Labs or other SS. Tell me if I am wrong.