Upgrading Tube Preamp from Audio Research LS-7 - Recommendations for better soundstage?

LS 25 or 26? Similar ARC house sound with a single gain stage and cathode follower with no feedback. The 25 mk2 and 26 are especially quiet but if you have a stash of 6922s then a 25 Mk1 is an option. The 26 has good stage width. Also really nice if you're planning on going balanced in the future.
Just a thought.
Good hunting.

There’s a Linear Tube Audio MicroZOTL MZ2 with external linear power supply and other extras for sale on US Audio Mart for $1500 that might be further negotiable.  Read the Positive Feedback and Part Time Audiophile reviews — soundstaging is definitely a strength.  Best of luck.  

Had a LS7 when it first came out and didn’t keep it long as I preferred my next pre, a Sonic Frontiers SFL1 over it with Mullard tube. I felt the SF was a more musical preamp but that’s just my opinion. Later I picked up a ModWright SWL 9.0 SE and very much enjoyed it but later had the bug to search for better and took home a ARC LS25 MKII and felt the ModWright at least in my system was more musical where I felt the ARC was a little on the cold side, not bad but didn’t excite me. Finally I settled on a ModWright LS36.5 and I’m pretty sure this will be my last preamp. If you’re looking in the $1,500 range I’d suggest reading up on the ModWright SWL 9.0 SE or find the current Anniversary model. It’s a great preamp and even though it’s been years since I’ve listened to an LS7 I’m pretty sure it’s safe to say the ModWright is a far better preamp. Forgot to mentioned I tried NOS on the LS7 and still felt even the Sonic Frontier was much better and the ModWright being far better.

+1 de Havilland UltraVerve 3.  I’m listening right now to my de Havilland Mercury 3.  See my review posted today of the Mercury 3 which is just the Big Brother to the UltraVerve 3.

I’m sure they share sonic characteristics.