Is there actually a difference?

Speakers sound different - that is very obvious. But I’ve never experienced a drastic change between amps. Disclaimer that I’ve never personally ABX tested any extremely high end gear.

With all these articles claiming every other budget amp is a "giant killer", I’ve been wondering if there has ever been blind tests done with amplifiers to see if human ears can consistently tell the difference. You can swear to yourself that they do sound different, but the mind is a powerful thing, and you can never be sure unless it’s a truly blind test.

One step further - even IF we actually can tell the difference and we can distinguish a certain amp 7/10 times under extreme scrutiny, is it really worth the thousands you are shelling out to get that nearly-imperceivable .01% increase in performance?

Not looking to stir up any heated debate. I’ve been in audio for several years now and have always thought about this.
There is a difference. Most systems benefit from having an amplifier that has characteristics that optimize the sound of the speakers (in your room, playing the music you listen to, at volumes you are comfortable with).

Your listening habits, room and speakers will make much more difference, provided you are using a well specified amp that can produce the appropriate amount of power. The quality of your program material will also make a huge difference.
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"Any yutz with ears can hear the difference between an amplifier before and after vibration isolation. Well, maybe not the bullet headed dude from Audio Review."

Do you mean Julian Hirsch from Stereo Review?

Kinda unrelated to this discussion but how much of a difference is there between a very early Levinson (ML3,ML9) and a current one or similar brand? I've always wanted to know.
I recently bought  a used Krell 300i integrated on a whim. It proceeded to wipe the floor with some amps that cost many times more.  Many amps do sound similar but wide deviations  exst too .  Which is right depends on your taste and system synergy.