The most simple way to describe it is -

With a class-A amplifier the power taken from the DC supply remains constant
regardless of signal power output.

The device(s) internal dissipation decreases by the same amount as the
signal power output (drive level) increases.

If there's any change in power taken from the DC supply as the power output
changes then the device is not operating under class-A distortion-less
conditions.

KISS. KISS. KISS. KISS.

To slightly change the subject, anybody who mentions a conjugate match
doesn't know what he's waffling about.

And if I remember correctly, a 6N7, a class-B dual-triode, metal tube was
specially designed to have a very high Mu and could be operated under very
simple zero-bias conditions. Each of the two triodes handled one half of the
complete audio sinewave.

With grids in push-pull and the anodes in parallel, you could get 10 watts
out of it as an HF frequency doubler.

But it would still take the skin off your fingers.

Ahhh! Happy days!
----
Punchinello.