Best Options For A Tubed Preamp - $2500 Or Less, Preferably Used To Maximize Value

As the title says, I'm interested in your thoughts on what are the ebst options for a tube based preamp, $2500 or under. I generally buy used to maximize what I can get. Definitely prefer a warmer sound signature, but not to the degree where details and impact are lost. 

What are the best values out there, in this price range, in your opinion? Any expertise, perspectives and experience greatly appreciated. Thanks.