Summertime ss amp Question

I would try a slightly different take on Rleff's suggestion and go with a Rowland Model 2. It's a better vintage of Rowland than the Model 5 (many argue that the Rowland 2/6/8/9 are the best Rowland amps ever made). It puts out 150 watts into 4 ohms, but what the amp really brings is refinement and build quality - both superb. Being fully differential balanced like your Atma-Sphere amp, it should substitute well for it with regard to cabling. It does not run particularly hot. Try to find one with the battery power supply - when run from batteries, there are only a small handful of solid-state amps that compete with it. PS - Like Rleff, I ran the monoblock version of this amp (Model 6's) and it was amazing how similar it sounded to my no-feedback triode tube amp.

Summer is almost over. Repost next year.

Nah, find a way to vent the heat. If it is your home, run a duct from area to vent with a quiet fan. Just pumping the heat into the walls could do it if you made a vent above area.
I used to think about just running a duct to the window for my amp with a whisper fan at the outside end...
All you would need is a hood like arrangement above the amp with a flexible duct...

Elizabeth, I have enough trouble edging my 6 foot SP Techs further and further from the wall whenever she's out without having a hood and duct to totally freak her out! Get real:) The MA-2s already occupy a coffin-like enclosure along an entire wall. No, a neat little ss box locked in the cupboard with the pre-amps, CDP and tuner is the ticket here. Unfortunately.

Wow those look hot. Do you get any ball rash mid summer?

Why not look at Luxman 800 or Esoteric A-03. These will at least compare to what you have even though they are above your range.