Pass Labs vs ARC

I am assuming, because this is in the Analog forum, you are referring to the Audio Research Reference Phono 2 SE and not the Ref 5 SE preamp. I just auditioned both the Ref 2 SE and the XP-25 phono preamps in my system in the past month and decided I liked the Ref Phono 2 SE better in my system.  The sense of space the Audio Research unit provides is pretty extraordinary and has been one of the most satisfying upgrades I have done. The Pass was tonally excellent and had particularly great bass definition but the image size it created was smaller and the image had less depth-- again in my room with my system. In my unscientific opinion, the Ref Phono sounded better in my system because I have an Esoteric C-03 as my preamp and I have consistently liked over the years systems which have either a tube preamp or a tube phono preamp but not both.  The same has been my experience with solid state units-- one is good , two is too many.  So if you have a tube preamp, I think the Pass unit may be your ticket to bliss. If you have a solid state preamp as I do, I would recommend your first audition be of the Ref Phono.  Hope this was helpful.