B&W 802 d4 with Tube Amplifier

I can speak as to the difficulty of driving the 802 series. The ARC will drive them but not drive them properly. The diamond series are power pigs, and it takes a lot of juice to drive them. I love B&Ws, but solid state is the way to go with them. 

Had been running (87dB) B&W Matrix 801 Series 2 with North Creek crossovers for 20 years with a Jon Soderberg modified Threshold Stasis 2 putting out about 225 watts per channel until replacing the Threshold with custom built Charlie Cocci Ultimate monoblocks; 2x6BL7 +4xKT77, about 100 watts each.  The tube amps absolutely kill the Threshold in every category, including loudness and bass response...gained at least 1/2 octave of bass extension with the Ultimates.

Don't belive the myth that big B&Ws need big solid state amplification.  Not only is it a myth, it's wrong.

I recently changed my amplifier from a 150 watt pre/power hybrid to a 40 watt tube amp.  The tube amp drives my 89dB/4 Ohm Audio Physic speakers at least as well as the hybrid, with better bass and soundstage. 

I’m running my 802d3s with mono mc275s and love it, also running 804d3s with vintage mc60s - both sound fabulous and the tubes really warm up the rather bright high end in my opinion

Years ago I was auditioning the new-ar-the-time 804S (no D tweeter then) with McIntosh pre, tubed MC275 mkIV and a SS Mac rated 250 Wpc. I preferred the tubed MC275, which I still own. But it is my understanding larger B&W do open up with more power. At the same store they had 802D with very large tube amps.

FWIW I auditioned ARC ref75 (not with the 804S) and wasn't my kind of sound, so what I liked might not be what you are after.

I would take a look at the better GaN amps ike Audions.