interesting and curious too, reading such different experiences with A90.
although only running some estimated 15 hours on my A90 have it set at 2,15 VTF and 100 ohms. will further finetune after a longer period with Dr. Feickert Adjust+ software eventually.
through the years i became used to lowering the back of the arm with many incarnations of the Colibri to compensate for a typical MC upper frequency lift.
although 'typical' with some reservations here, not all MC have this tendency but alas.
so i caught myself doing the same with A90.
but came back from that tendency real soon. the A90 likes it level.
we see many teaming up their A90 with tangential arm with great succes. well i can report too that A90 is an amazing match with the Airline.
the whole TT set-up totally dissapeared now, i did not yet experience this level of playback with the same TT owned for 15 years.
patience is good.
LOVE the A90.