Tube preamp for Pass Labs amp


I am considering changing around my system and I am interested in knowing what (tube) preamps would be a good match to Pass Amps. Any suggestions? Less than $3000 would be nice new or used.
aronsss
Aesthetix Calypso with NOS tubes. There's one listed for $2,500. I had one for approx. 3 years and regret selling it.
I agree with Pdreher. I use the Calypso with NOS tubes also, with my Pass Lab XA 30.5, works very well. I'm sure there are many preamps what would also work very well.
I have loved the hybrid tube kW linestage from Musical Fidelity with the Pass and FirstWatt gear I have paired it with. Check out the great Michael Fremer review in Stereophile. There are other nice reviews of this around the web too.