I know that the B&W 805s have come a long way since I bought my pair of 805 Matrix speakers 25 or so years ago. But I liked all three of the amps that I have owned with those speakers, and they were all tube amps. My first tube amp was probably what you would call entry level; it was a Cary SLA 70 and although I liked it a lot, it was the one that was lacking of most sonic aspects that one would listen for in a system. Next I had a pair of ARC VTM 120s, and that amp/speaker combination could rock out or play quiet. I am now driving those same speakers with a Cary V12 (50 wpc in triode mode or 100 in ultralinear) and I cannot remember the last time I switched to the ultralinear mode.
But with all that typed, and with absolutely no sarcasm intended, it is quite possible that my ears are not as well tuned as yours and therefore that I am not as discriminating. It is also possible that I am easier to please regarding presentations of sound that you might not tolerate.