About the XDA, the volume was implemented so that for the first several steps off 0 it would increase rapidly, then for the rest of the range much more gradually. For some using it as a pre amp this was too rapid(some others with lower gain amps and or less sensitive speakers, no problem), myself included, so Emotiva offered to adjust it for anyone who prefers it. I understand this is an open ended offer, and it involves some kind of a firmware change.
Anyway, I've since had it back from Emotiva and the volume works about like my Onkyo 876, you have to turn it up about 25 db off 0 to start to hear audio. The remote adjusts the volume without issue. It's my first DAC and I'm really happy with the performance and the option to go without a pre amp.
But back on topic, I wasn't recommending an Emotiva option for Stream per say, just that auditioning different brands would be a good approach. I'd add that Parasound has some good options in his price range and some of their amps have a bias towards class A though they are class AB amps.