I just did my first audition of my AR 90s. I redid all the foam surrounds as soon as I bought them since they were totally disintegrated. Good news, all the drivers are working and they sound good. I am driving them with a Yamaha a/s 500 rated at 85wpc 8ohms. I can get decent sound level but bass is weak compared even to my AR2ax. Also, upper mid seems dominant and somewhat harsh. I attenuated the UMR one step down and it seems more balanced that way. I am pretty sure that I am not hearing anywhere near their potential with this amp. I have a 2600 cu. ft space on a concrete slab subfloor with cinderblock walls and probably 1/3 of the perimeter is glass. After much research, I have narrowed down my amp choices to vintage NAD 2200/2400 or Adcom GFA 545/5400. It seems that I can pick these up for around $250 which, with a decent preamp, falls within my budget. I would be interested in opinions on suitability of these for the AR 90s. Of course, I am open to other suggestions. The NAD preamps also look attractive since they have decent phono quality which is a requirement for me since a I have a large vinyl collection. For this reason, I am also considering an Apt Holman preamp.