How hot is pure Class A solid state vs. SET?

In general, I would say a SET will be hotter. I could put my hand on my Aleph 3, comfortably for 20 seconds. The hottest amp I have had was a Viva Solista, you could coook breakfast on that. It is'nt only dependent on the tubes with a SET, the Solista was very hot with 2, 211 and 2, 845 valves. I use an Ayon Spark too, the same 623C tubes as the Almarro and it is'nt that hot.
So it must come down to circuit design too, as well as the tube.
The clear winner as a radiator, was the Viva Solista

David12 makes a good point, tube type and overall design are factors to consider. My amplifier is 300b SET class A, 8 watts per channel. After being on all day(10-12 hours) the amp and transformers are only warm, never hot.I would think the 845 and 211 tubes as well as their respective power supplies will generate more heat.

Al touches on it without being .....explicit.

Heat and temperature are 2 different things. A lit match has a far higher temp than even the most ambitious amp, while 100lb of class 'a' will heat a small house.

So, while the 100watt bulb will burn you try to unscrew it when on, the warm to the touch 'a' amp will actually put out more heat.

As kind of an aside, didn't I read somewhere that a person radiates about as much heat as a 100 watt incandescent?

Also, from the FWIW department, the very high efficiencies quoted for 'd' amps? In the case of the ICE modules 80%+, for the ASP modules at least, is for 'Plug-to-Speaker'. And than only at full power. Lower power is much less efficient, being close to traditional A/B at reasonable levels.
Other 'd' amps may NOT include the PS and quote in the 90s, again a full-tilt.

Magfan, interesting (and good) comments.

As kind of an aside, didn't I read somewhere that a person radiates about as much heat as a 100 watt incandescent?

I hadn't ever read anything about that, but some quick calculations indicate it is correct.

Obviously there will be very large differences among different individuals, but if we assume an average of 2250 calories burned per day (150 pounds x 15 calories per pound), and that as indicated here 1 food calorie corresponds to 4.2 kilojoules = 4.2 kilowatt-seconds, the corresponding power consumption calculates to 109 watts!

Best regards,
-- Al

Sheesh!
When somebody says....'Do the math'! You take them seriously.

And yes, following all those conversions thru......spot on.

For the class 'a' folk, that's why a cabinet or other enclosure is generally a bad idea. Solutions? out there, and maybe one day I'll publish MY solution which not only cools the gear but keeps it clean and away from micro vibrations which some find......disturbing.

I'm sure I'm closer to 120 watts+, while my tiny neice probably barely breaks 75!