Unsound, there are detailed measurements in the review by Stereophile and further explanation in the Soundstage review. The Stereophile measurements on the XA30.5 estimate a maximum 150 watts into 8 ohms, and 200 watts into 4 ohms after converting into AB. So, this little guy in 4 ohms provides the first 60 watts in class A, and the last 140 watts in class AB.
Peter, your description parallels what I hear. I believe many people underpower their speakers. The XA200.5 sounds incredible at high volumes. There is no strain whatsoever. It is relaxed, effortless, perfectly dilineated, and majestic. I think that recorded music has an intrinsic optimal volume, but now it sounds so good even when blatantly too loud. If I play Mahler 8 or Gotterdammerung for the neighborhood, the needles on the front will flinch slightly at 400 watts into 90db speakers at 4 ohms. The other thing that is remarkable is how good it sounds at very low volumes, even the bass. Whether at a whisper or a roar, the Pass maintains a firm grip on all the drivers.
Peter, your description parallels what I hear. I believe many people underpower their speakers. The XA200.5 sounds incredible at high volumes. There is no strain whatsoever. It is relaxed, effortless, perfectly dilineated, and majestic. I think that recorded music has an intrinsic optimal volume, but now it sounds so good even when blatantly too loud. If I play Mahler 8 or Gotterdammerung for the neighborhood, the needles on the front will flinch slightly at 400 watts into 90db speakers at 4 ohms. The other thing that is remarkable is how good it sounds at very low volumes, even the bass. Whether at a whisper or a roar, the Pass maintains a firm grip on all the drivers.