Have you considered going the minimalistic route (aka a passive preamp)?
Here’s a review of one that meets your budget: The Truth Review
Upgrading preamp. Best for under $1K
I am planning on upgrading my preamp and was wondering what would be the best preamp for under $1K. Currently have the Rotel RC-995 with a B&K ST2140 amp and Vandersteen 2ci speakers. I like to stay with SS unless their is tube pre in that price range.