I recommend you go with a tube preamp. Look for something based around the 6SN7 tube, with point to point wiring. Ideally it will have tube rectification. Even better if it has tube regulation. To ensure max value, I’d probably look for something used, although my current preamp is the first piece of equipment in many years I purchased new and willingly paid full retail for. I’ve never suffered from buyers remorse on this purchase or any of the current items in my system.
Take your time. Read on this forum. Certain builders/companies/pieces of equipment (especially those which are relatively small operations or "boutique" builders) consistently come up. For instance, Don Sachs, Atmasphere, Supratek, Aric Audio, First Sound, DeHavilland. Rogue & Primaluna are pretty well thought of. Before I started hanging around here I'd never heard of some of these guys.
I don't really know what your for-real, no-kidding budget is. I found that, the more I read the more i eventually increased my budget.
Here's why that might be a good idea. If you buy right once, you don't have to upgrade. I started reading comments from some folks that once they bought a certain piece of equipment they were "done" upgrading that part of their system. Personally, I hate churning equipment, losing money on buying/selling, auditioning and fretting over my system. I just want to listen to the music. I know there are some folks who really enjoy the swapping in/out process. There's nothing wrong with that. It's just not me.
Do you need a phono stage? Or just a line stage? There are many fine builders/companies out there.
Why do I recommend this? For sheer beauty of sound. Tone. A well designed and well built tube preamp will give you this in spades. It will help illuminate the artistic choices the ensemble (regardless of genre) is making. For instance, you can hear when a vocalist is smiling when they are singing. Sometimes it seems I can hear when the bassist is looking at the drummer and nodding and they are in sync.
Music should be relaxing and beautiful. My tube preamp does this for me. My buddy, who used to be way into tubes, now is using a Luxman integrated that also sounds very, very fine. I think it’s a 590 or something like that. It also has a beautiful, rich tone.