How to evaluate amps that are not broken in?

Audiofeil is right on in my experience! Acclimation of the human ear and mood are my 2 most important break-in variables. I have never seen/heard in my 35+ years in the hobby a component of mine change significantly enough to really make a strong claim about break in. You know sometimes you listen to your system and think it's magic....I'll never change a thing! And other times its just OK. It's probably not the components. I agree warm up probably makes a difference as I suppose everything settles and becomes more stable but it is still not real significant. Just my opinion. It certainly makes for good conversation among us audionuts.

I've got a friend who is just becoming an audiophile and he bought his first high end cables and declared "I think I already hear a difference but maybe it's just in my head."..and I said what does it matter!!!

If you like it initially, then you'll like it as much or more days and weeks later. Vice versa.

The sound of a new amp (or any amp) has more to do with speaker/amp interface than break-in, IMO.

(Bill ,Tvad)

Amen........

Finally a voice of reason

PS
If, let's say a $10,000 cdp sounds like $3000 cdp out of the box
and manufacture claims/says it will take 800hrs for full burn-in process to get the best of it..........well, if you listen for about 3hrs a day it will take about 9 mounts of anticipation, confusion, insecurity.

And then........you hear the first scream, first cry and you love it.

It is a boy!!!!

there is no reason to assume that if you like the sound of a component when it is fresh out of the box, that you will still like it after 400 hours.

i have had experiences in which i initially liked a component but then did not like it after 300 hours.

very rarely have i had the experience of initially disliking the sound of a component and then liked it after 400 hours.

if amplifiers are not broken in , it is wise to wait until the amps have been played for at least 300 hours before making a purchasing decision.

Sure Mrtennis.
But it is more of the search for the new adventures and boredom with the old then anything else.