This is again a very subjective and personal view so again always take my opinion with a grain of salt. I personally have listened to my speakers with Krell KAV separates Integrated and AMP @ 250w per channel and compared them against my Rotel RSP-1065 5 x 100 receiver.
To my ear what I found in MY regular stereo music listening levels 50-80db it was hard to decern the difference. My mind thought the Krell had a little more detail. That was it. The soundstage seemed equally as big and deep. In the lower listening levels I could discern that the Krell had more detail. Why? I do not know. Maybe the Rotel 1065 (which isn't a slouch) did not process low level sounds as well. When I turned the Rotel up to the higher levels it did seem the receiver was definitely working hard. My volume level was cranked up to like 68+ something. I never recorded the actual db on the spl. The Krell at those levels presented the sound with greater efficiency and I do not think the amp was anywhere as hot as the ROtel. This is the reason why I have also been looking at the IRD monoblocks. Again I am not looking into theses monoblocks for the sake of getting a better sound. I am looking into them due to the fact that in DTS or DD mode I have my volume up to 70+ and I think I am working the 1065. By having separate power to each speakers it would let the receiver work less. Since the canadian dollar is high, purchasing the IRD monoblock seem like a great deal. Also I can easily see that my current speakers are not as efficient as the Axioms and the Monitor Audio speakers (I used to have the Silver S6)
Saturn
