Well ... and this is said with love and respect, in friendship, not antagonism, and only because of a century of science, and four decades of experience in the pro world, where results need to be really real, to justify a skinflint owner's expenditure ... you got a dull and uninvolving sound because of sighted testing and multiple layers of bias.
The gross ab initio bias was believing there could be a difference. (How likely is that, anyway, with a speaker where two-thirds of the sound power is generated by its own internal DSP and active amp? Literally everything below middle C is nothing to do with your choice of amp. But anyway ... )
In some hidden corner of your subconsciousness, you bought into the old audiophile mantra that clean + clinical = dull and boring. And so on, and so forth. Whoever you are, you are not the one human among seven billion who might be immune to bias. I absolutely guarantee that if an alternate-you in an alternate-world had tested your 12 amps unsighted, you wouldn't have heard any difference at all. That has been demonstrated over and over and over again.
It's as simple as that, I'm afraid. Again, said with respect.