Looking for a new (preowned OK) line stage under $5K: suggestions?

With my Pass XA25 I eventually added the Pass XP12 preamp, and it’s the best match I’ve found, especially since you are seeking a touch of midrange bloom.  Along with a couple of different Audio Research preamps, by far the best I’ve used. Problems with Pass would be new price is above your target, $5900 I think. And also there likely will be a wait to get it. 
 

in any case, have fun!

Big fan of the Zesto Leto. Problem with the Audible Illusions is that you must be very careful with retubing. Berning is also excellent but he isnt selling his own name brand any longer and he has no LTA offering which competes with his last preamp design with his name on the component.

"as a touch more midrange bloom"

Any tube unit will do.  I did that once.  If you want the tone of one equipment to make up for another, give it 15 years and you will end up replacing everything seeking ultimate sound.  Aim for neutrality as some source materials are warm, others sibilant. 

In a true reference system, the worst part of it is the LP or the production studio. 

@jumia 

From my experience DSP is a great way to remove the musicality of a system. While improving… still touching and fiddling with a signal is the quickest way to low FI. 

I recently bought a Pass XA25 (an amazingly great sounding amp) that is proving how superb my Schiit Freya actually is. I don't recommend buying a Freya (Freya + now) as although having recently garnered a "Class A" rating it's way too inexpensive to fend off audio price snobbery and hey...who needs that?