Tubed pre to go with Aragon 8008BB

My current equipment is Northstar 192 Transport and DAC, Aragon 28K Pre and 8008BB amp, Von Schweikert VR4SR's, and Gurellia wire throughout. I think that I am close to where I want to be but would like to try tubes to see if I would like the sound.
I think that probably my current pre is my weakest link and have heard that the pre is a good place to put tubes. I want something trouble free, used is fine, $3,000 is probably tops. I like mostly classical and rock. Any suggestions will be appreciated.
i don't think you could go wrong with a supratek chardonnay at $2100 plus shipping and whatever extra options you want (remote, home theater bypass, balanced outputs...).
Audio Horizons TP 2.0 would be the one to beat IMHO. Try one, with their Money Back Guarantee you have nothing to lose.

Send your transport and DAC to Steve Nugent and you'll keep the preamp. If you want a tube sounding preamp then go buy a MapleTree tube preamp, comes with a 10 day trial. Steve will make your digital sound right and you won't worry about the preamp.

Happy Listening.
Thank you for your responses. Interesting reading up on the Audio Horizons and Supratek products. Both are definiely well spoken of.
Bigkidz, I could not find MapleTree in the manufacturer list and unsure how to contact Steve Nugent.