Tube pre to use with Bryston 4BST

Hello Good People -

I am using a BP-25 with my 4BST to power a set of ML SL3's. I love my Brystons but on certain classical & jazz recordings the sound is a little too much 'in my face' to suit my taste.
So - A tube preamp may be in the cards. Any suggestions as to what might take the 'edge' off the 4BST?
BAT has been recommended along with Blue Circle... One caveat, however. I have everything tied together with balanced (XLR) interconnects (including my primary source, a Krell KAV-300) and I do not want to have to invest in RCA cables for the sake of a pre that doesn't have balanced inputs/outputs.
I haven't an unlimited budget - maybe 2500-3000 bucks new or used.


Thanks in advance for any suggestions.

Gpsguy.