I have listened to my new RSA SR-71B for a couple of weeks now. I'm very satisified! Worth the price... and no need for "tube rolling" which I'd grown frustrated with on desktop tube units; it sound great out of the box.
I'd like to do more of a review soon, but I haven't been analytical about it, just enjoying it. I also plan to get a balanced cable soon, so I can test it in unblanced in, balanced out mode.
I find it authoritative, bold, strong, powerful, detailed, flat, satisfying. Great "jump factor" when there are dynamics. Treble is extended and present as needed but not too forward (a pet peeve of mine). No added emphasis to sibilance, which is important to me.
It is a great match to the HD650. My Senns are a bit modified: removed the foam and added Cardas Clear Light cable, so it already is more detailed and has better upper midrange and treble than stock. (I don't use it with my PFE 232, because they do better with the Arrow which has a midrange forwardness on gain setting "1" that helps compensate for the Phonak's v-shaped response curve.)
I read here that there was an update to this amp recently? If so, mine came after this update. It is wonderful. I will use it for stationary use primarily and mobile at times. The size is 2-3 times bigger than the Arrow 4G that I have, which is good but doesn't have the purity of treble, solidity, and graceful and flat treble of the RSA.
http://www.raysamuelsaudio.com/products/sr-71b
