Ultimate headphone amp?


What are some of the better headphone amps out there for use with HD650's? I have had the Earmax before which was very, very enjoyable. Either tube or "warmish" sounding solid state will do. I have read reviews but not listened to Sugden, SinglePower and RudiStor. I have tried Headmax before but did not like the slightly cold/sterile sound, I prefer the slightly "tubish" or "euphonic" with "richer harmonics" sound. What else should I consider?
flyski
Musical Fidelity X-Can V3 would be a good consideration. Very nice synergy w/ Sennheisers. Upgraded power supply is a definite plus.
Cary 300 sei integrated has an hp jack and cut-out switch for speaker outs so you can use it to drive your entire system if need be. The 6SN7s and 300bs give you lots of rollling options.
We just compared the Consonance Cyber 20B (basic version) to the very highly regarded Ray Samuels Raptor. The Ray Samuels is almost twice the price. We used the sensational $400 AKG's. The Consonance had better tonality, more musical while still being more open and more transparent. For a little more money, you can buy the model 20 with separate power supply. Consonance makes great built and great sounding products. Bargains for the price.
If you can find a Berning MicroZOTL grab it-excellent match with Senn 650's.
Joe
Cary 300SEI. The phone jack connects directly to the transformers!! No opamp involved here. I used this combination in the past.