Need Help Choosing a Tube Preamp for a Classe Amp

I have Thiel CS3.7 speakers and a Delta 2200 Classe amp. I'd like some suggestions for what tube preamps to audition to match with this amp/speaker combo. The Thiels are wonderful but unforgiving of things like tube rush and I have little interest in tube rolling or high maintenance. The Classe Delta is a fairly neutral SS amp. I'd rather not spend more than $3000 used...or is that unreasonably low? I've listened to the VTL 5.5 and was impressed.