Concerning tube amps for HT:
I find my (4) Mac MC 275VI`s mono`d for the mid and high frequency tri-amplified Mac XRT 30`s main L/R fronts in my A/V HT to have no problem delivering un-clipped very HQ audio during any BR/DVD movie ever played here through my system, even my nearly 60 year old electronically restored by me, MC 60 "tuber" doing center channel duty driving a timbre matching center channel Mac XR 27 speaker hasn`t been heard to clip yet..
Now, waste heat is an issue, especially during the summer while watching a movie here in NE. FL. !!
My HVAC set @ 75` cycles very frequently during and for some time after the system is powered down !!
Around 13 amps @ 120volts current drawn for just the (4) MC 275VI`s, MC 60 and 120" screen projected Sony Theater grade 4K projector, and some low level A/V equipment (OPPO UDP-203, etc.)
80 Hz and below are well handled very well via (2) MC 1201`s power wired for 240 volts via a 30 amp 10 gage dedicated circuit.
But those Mac MC 275VI tube amps sound so smooth, whether pressed in to tri-amp service for straight 2 channel music listening, or same in HT L/R front duty..
My Integra DHC 40.2 can do some level of Atmos, as I seem to remember, but I`m uninterested in pursuing, as the Mac XRT-30`s have such a very good sound stage in conjunction with (8) RS Minimus 7`s (2) per channel vertically stacked and ~ 30 degree splayed for L/R side & rears, for very realistic surround effect after tuning/voicing via the Integra..
No more HT amps/speakers needed, nor desired for this old fart !!