Check out the deHavilland Verve tube preamp. It can be found for less than a grand. This tube pre has amazing, warm detail. I personally use the deHavilland Ultraverve preamplifier with my Bryston 14Bsst with very nice results for my ears.
Preamp for Bryston 3BST / Magnepan MG1.6QR
I am interested in people's experience with preamps in a Byston/Magnepan setup. I currently have a Bryston BP20 that results in a very thin and cold midrange. I am looking for something fuller and warmer. I have read good things about the Rogue preamps with Bryston amps, but I'm interested in how the Magnepans stir the mix. Thoughts anyone?