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


I want to replace my ARC LS-7 tube preamp. I fell in love with the bloom and warmth when I bought it. But it doesn't have the soundstage focus or width that I had heard from others I had demo'd at the time. I think I want both now!

Any recommendations on upgrades? - tube for sure, but something with better soundstaging - more focus and width. Open to used gear like an ARC SP-16L or Prima Luna Prologue or Conrad Johnson Classic or PV15 or Rogue 99 or??? These are just some I had seen used in the $1000 - $1500 range which is basically my budget.

Don't need a phono amp but would use one, don't need a remote but would use one.

My system.
- Digital and vinyl sources
- ARC LS-7 Tube preamp
- McCormack DNA-1 solid state amp
- Martin Logan SL3 Electrostat/dynamic woofer

Thanks much.

1trackmind
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.
Those are some great suggestions. Ones That weren’t on my radar. Been wanting to venture into new territory. Thank you all very much. The hunt begins. 
Have you read about the Don sachs model 2? Have you read the preamp deal of the century thread regarding the Supratek preamps? I'd add those to your list for your consideration. Both are very highly rated custom made by hand products from very small companies, So they don't get a lot of press.
Well I found a UltraVerve 3 with remote and lots of tubes to roll. Should get it Friday. Thank you everyone for your great info and tips. Truly appreciated.