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

++2 Cary SLP05 ultimate upgrade. I bought mine used for $4350. It’s da bomb!

No pre-amp will solve the problems created by room acoustics. A better approach than to change pre-amps might be to switch to a loudspeaker which interacts less with the room. A dipole planar has significantly less floor, ceiling, and side-wall reflections that does a cone & dome design, though of course greater front-wall reflections (which can be dealt with).

The Cary Audio SLP-98 new comes in right at your stated price goal. That’s with some upgrades tossed in. I’ve had mine for over a year now and it’s a keeper.

For under 5k used you can get a rogue RP-7 and some nice NOS tubes. I'll agree with bdp24 though when he says a preamp is unlikely to solve your problems. If there's not enough stuff in the room and it sounds too live maybe appeal to your wife by seeing what could be added to soften thr room. Like put a rug down if it's a wood or tile floor. Or get some window treatments if there's a lot of glass. These types of things, while not nearly ad exciting as buying a new piece of gear will make a marked difference in how the room sounds.

I’d get a preamp using the 6sn7 tube. Mod Wright, Cary, Supratek, Aric among others make tube pre’s using this tube. Many Pass owners like the Cary.