Tubes to solid state for amplifier path...

Abucktwoeighty
Your Pass will not run any cooler when it "switches", er I mean, leaves class A and transitions into B. What an interesting thread as I'm taking the digital plunge and trying a bel canto S300. My ARC VT100MKII is currently out of service at the moment (re-tube, patiently waiting for tubestore to restock 6550C; btw upscale deserted ARC VT owners, for no *real* reason; therefore I suspect the tubes may be questionable to begin with and the ARC VT's bear that out but, more than likely, whoever is re-tubing/biasing is not doing it properly).
I live in Virginia and summers can be quite toasty. Even with a good central AC our townhouse seems like it struggles to stay cool on those 95 degree humid as @#$@# days. The tube amp will only make matters a bit more toasty. I will not be going to solid state for the preamp though, as this is where most of the magic comes from.

I live in northern Minnesota. I actually like the heat my MC275 gives off most of the time...

Minnesota has actually recorded the highest dewpoints anywhere in the world. We get very humid summers, with highs in the upper 90s and low 100s (usually in July). The smallest window air conditioner I could find will easily keep up with our S-30 in my living room- its class A and 30 watts per channel.

But- I would be looking into a class AB tube amplifier before I went with transistors! A class A transistor amp is going to make nearly the same heat as a class A tube amp- the filaments are a minor concern. IOW most of the heat comes from the class of operation. So a class AB tube amp will make **less** heat than a class A transistor amp will, assuming that they are about the same power.

I like to fry eggs on top of my class A amps.

clayton audio. I have the m-300's. You can barely feel the heat in my room which is somewhat small. They are class a and they are awesome.