For used I would see if you can find an Ayre K5xeMP. It is an outstanding unit for the money and will work very well with the Bryston. You should be able to find these used in the ~$2K range.
For new, check out the Musical Fidelity M6S Preamp. At $2K, it is an amazing value and punches way above its weight in terms quality because it is made in Taiwan. I am an MF dealier. PM Me if you are interested.
