I believe in my ears,{/QUOTE]
That is unfortunate.
Actually, it is your brain that is messing with what you think you perceive.
and I know that amps, preamps, and dacs have a sound signature of their own regardless what anyone says.
That is your downfall in this hobby, you don't read and listen to what has been discovered in psychoacoustics and human biases, how easily one can be fooled.
How poorly your brain behaves and fools you.
No wonder you went through all those amps, etc.
..... I have A/B tested many different combinations and no doubt they do have their own sound signature. ....
And, how did you control for bias. How many trials with each pair per test? What was the statistical data? Perhaps you were just guessing.
Might be best just to continue stacking up those amps and speaker and be happy.