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
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.
You should look at the Ray Samuels Emmeline II Raptor. I did not like the Sennheiser 650 at all until I got that amp. You can tailor the sound a bit by tube rolling and Ray is very easy to deal with. The Single Power has bit more tube lushness than the Raptor. You can read reviews of these products at
http://headfi.com/
Hifi+ reviewer-decidedly not an enthusiast of headphone listening, really loved the Stax offerings he reviewed in a very recent issue...System series two w/ energizer, I believe. Very expensive, and maybe a bit terrifying. Sounds like you have to get strapped in, with a complimentrary bit to keep you from biting your tongue. How real is that!