I haven't heard one myself but have a good friend that says the REF75 is a very special amp, Read all the reviews and you will find how amazed people are of the output and sound from that amp. Now with the REF80 out, maybe prices will fall below $5k. They seem to go for around $5500. My friend is driving the Wilson Sophias which are 89db and he says the REF75 is more than they need. You can't go wrong with more power than you need. From the reviews it really seems ARC nailed the design so you may want to stretch your budget a bit and check it out.
Wanting to try a tube amp.
Looking at an ARC Ref 110 to go with my Ls28se. Used is fine with me want to keep it under 4k. I only stream thru a node 2i and Audio Mirror iii se. Speakers are GE Triton Refs. Any other thoughts for me? Room is 14 wide 24 deep 8 high. Listen to mainly Pink Floyd, ELP, and rock in general. Don't play loud, about 75db. I'm already deaf and have a pretty decent noise floor in my head to compete with. Thanks.