I used a Cary 2A3i and currently own an Aspen Audio 833 and an Audiovalve RKV. If your taste runs toward rock or funk or R&B, go with the Audiovalve. If more classical/jazz/acoustic, go Cary. For compact size and low heat output, Audiovalve. For ability to drive mod/high eff speakers and multiple inputs, go Cary. Aspen Audio is a nice alternative at a much more attractive price. I have not heard, but many folks swear by the Cary 300bsei as the ultimate tube amp for dynamic phones. The Carys will be about 2-3x the cost of the RKV, the Aspen 60%. Hard to go wrong with any of these amps.