Why do amps sound different?

I'm thoroughy convinced that we don't know how to measure some things that really count- and that's why amps sound different at similar specs.

What are those "things"? I have no idea.

My bet is that the perception of reproduced music is extrememly complex, and we humans are still not as smart as we believe ourselves to be.

Amps are like ice cream flavors. I agree with most threads here but, amps embellish certain freq. ranges to tickle our ears. We like what we like! Most really nuetral amps don't sell that well.

We need to bring back Julian Hirsch from the grave to recite all his articles in High Fidelity magazine that covered that subject. Do you remember Julian? He was of the test bench school.

Nah, leave him there. It's threads like this one that demonstrate how few people understand what the test bench tells us and doesn't tell us.

You don't listen to an amp. You listen to a system.

Danlib hit the nail on the head. Two amplifiers can measure nearly identically in all of the usual tests and yet sound significantly different. Why? Because amps are filled with passive parts like resistors and capacitors and wire that all sound different even when rated at the same value.

Anyone who has actually listened to different brands of resistors or capacitors of the exact same value knows this. I believe dialectrics have a noticable effect on sound and they are everywhere including the circuit boards.

Even the solder used can affect sound quality. Recently a popular high end manufacturer changed to lead free solder and all of their gear actually started to sound different (in this case better, thankfully).