Asimov wrote:
"I`m sorry but it is an erroneous conclusion to think it cools (when
signal exits)."

The Class A amplifier gets all its power from the d-c supply and it is
constant, signal or no signal. With signal power output, some of the
power in exits to the load.

I`ll use Cecil, W5DXP`s argument. Energy must be conserved. Energy in
equals energy out. If some goes to a load it does not stay within the
amplifier to make feat.

Asimov also wrote:
"---linear source not operating Class A?"

I`ll give an example. The Class B amplifier is biased near current
cut-off. Current is near zero when the signal is. Yet, output can
favorably vie with that from a Class A amplifier for purity. I learned
that nearly 60 years ago when I built my first 6N7 phonograph amplifier.

Best regards, Richard Harrison, KB5WZI