Best Preamp round $8000

Hi, I owned the Ref 6 for a while. Replaced it with a (used) FM Acoustics. No comparison: dynamics, clarity, naturalness... I could go on. Mind you, the AR is an excellent device; the other one is better. Cost however was a tad higher at ~10k.

The Ref 6 is a joy to listen to.  Quiet is dead quiet all music comes through clean and natural.  The preamp is not fatiguing at all.  The minute you turn it on you will appreciate what it does.  I have owned the Ref 3, Ref 5 and now the Ref 6 and have been happy with all of them but the Ref 6 is truly outstanding.  I also have a Dartzeel preamp which is amazing as well.  All things considered though I like tubes and the Ref 6 will stay in my system for some time to come. 

a used luxman c-900u might fall into your price range. it’s awesome all around
i also like the ml 523 and 526 very much but would still look for the luxman.

fwiw i owned a ML 326s and an ARC Ref 3 back a few years ago and just couldn’t shake the fact that the ARC was like an empty box compared to the ML and i felt that the ML sounded better. also the construction and operating software were as good as it gets. having owned a 326s and luxman c-900u imo that gap probably still exists. luxman and ML put serious money into their products. arc not so much. if i’m going to spend 8k and up for a component it should look as good as it sounds. i don’t buy the theory that the box doesn’t matter and that the manufacturers of low budget boxes are putting their money on the inside. the preamp is the unit that you most interface with so you best like to operate it as well as look at it. just my opinion of course.

For ~$5K used, I'm using a VAC Renaissance MKV and love it.  Running a pair of a NOS Mullard 6922's, it's pure preamp bliss to my ears.  I realize we are all going to recommend our pre's but thought I'd chime in.