If you've been happy with the passive preamp perhaps an active preamp that is transparent, but provides some warmth in the form of tubes would be nice to check out. The Modwright 9.0 SE comes to mind. These are showing up under $2k used here and may not be much more than $2k new. A very nice preamp.
If you want something a bit more musical and warm, a used Joule Electra LA-100 MkIII will do the trick, or perhaps a Cary/AES preamp. The AES preamps are a great value for the money and well under your budget.
If you want something a bit more musical and warm, a used Joule Electra LA-100 MkIII will do the trick, or perhaps a Cary/AES preamp. The AES preamps are a great value for the money and well under your budget.