Actually, one does need a blind test to determine if one is actually hearing the difference, or if one is experiencing the "It's my new XXX, and it's better" phenomenon.
The reason many insist that "all amps sound the same" is because of the amount of data collected from blind tests.
If an amp is linear in response across the bandwidth and has sufficient current to deliver the SPL required for the performance through the speakers connected, without distortion, hearing a difference will be quite difficult, if even possible, between two amps.
This is why I now have a pre amp level switcher. Should we want to, we could do level matched, blind listening tests with instant A/B switching between two amps through high resolution speakers such as the Legacy Signature SE's or the M100's.
SO ... you are invited anytime to bring your amp over, do the test, and have adult beverages after.
