Tube preamp for Bryston 7B-ST

I'm thinking about switching out my Bryston BP-25 preamp to a tube preamp. While my bass is solid, the midrange can sound congested with dense musical material. There are a number of choices with great reviews. Please help! I'd love to hear about your experiences combining tubes with SS amps, especially the 7B-ST's. Thanks in advance.
Sonic Frontiers L2 or Line 3 are good choices.
I like the idea of tube pre-amps with solid state amps. Tube pre-amps require little maintainance, tubes are generally reasonably priced. You can really get a great sound with this combination. However, I've listened to the Bryston preamp and have not found it to be congested in the mids. So I'm not sure that your switch will get you where you want to go. Have you listened to other pre-amps and did it make the mids sound better? Speakers, cabling, and the listening room (including speaker placement) can have a huge effect on the midrange. Since I don't now what you have it's hard to comment.
I have another thread open on nearly the same subject. I am looking to upgrade my CJ PV12 tube pre-amp that I run with my 4B-ST. I initially was looking at a SS pre-amp, but now I just read the review of the CJ Premier 17LS in Stereophile. I plan on auditioning it. If you are looking for good tube sound, give CJ a listen.
Ozfly: A friend of mine has the 7Bs and started with the BP - 25 and after several different go rounds ended up with the Lamm L1. Its been in his system for about a year - thats a record I think. The Lamm is tubed and he says (and I hear it) that it warms things up. The only issue is those pesky tubes. Good Luck
I previously owned a BP-25 mated with my 4B-ST and while it was dead quiet and brutally revealing it was too sterile for my tastes. A Rogue 66 tube preamp warmed everything up nicely. I had spoken at length with Bryston before my first foray into tubes and their opinion was that tubes do in fact color the sound but I made the leap anyways... In my system the analogy (using televisions) would be that the BP-25 was a HDTV black & white set - you could see everything in complete sharpness but the subject matter was sterile - the Rogue while less detailed offered color and was in the end more enjoyable.
Thanks Abstract7, I am also exploring power regenerators and would certainly like to try before I buy. Since relocating from Boston, it's not real convenient to bring stuff home, so I appreciate all the feedback from fellow Audiogoners. By the way, my system is listed in the Virtual Systems (Large Room ...). I hope my use of "congested" is correct -- it just doesn't sound like everything is coming through clearly when a lot is going on. Rgd, I love your analogy. Argent, if you would be kind enough to let us know what you think when you audition the CJ Premier, that would be great. Thanks all. Any more feedback would be appreciated.