Pass Labs XA60.5 Monoblock Power Amplifiers

Ryan Coleman has posted a review of the Pass Labs XA60.5 Monoblock Power Amplifiers ($11,000/pair) at Positive Feedback Online. His conclusions:

ets sum up. These amps are not perfect. No amps are. But their flaws are so trivial in the grand scheme of things, and their strengths so considerable in all the ways that relate to how music sounds, that it is only prudent to consider these amps a stunning success. The XA.5s have an organic tone that is seldom found in solid-state amps, and one that I've never found in a class AB amp. Tube lovers will never find the kind of bass control that the XA.5s deliver in their favorite valves. If one can accommodate the price, the space and the heat output, selecting amongst the 30 watt stereo amp or the monoblocks rated at 60, 100, 160 and 200 watts may very well be the last amps many audiophiles will buy. And allow me to make this blanket recommendation: if you're thinking of buying the XA.5s, and you think a particular model is the right size for your room/speaker/preferences, get the next larger model.

The primary weaknesses I found in these amps were a function of needing more power given how low the distortion levels were. As the music was so pure, so unadorned with annoying digital artifacts, I routinely found myself cranking the volume to the point where the amps ran out of juice, as evidenced by the bias meters jumping around. Had I a larger model of the amps, this would not have been an issue (however, I doubt its in the DNA of the XA.5s to deliver sledgehammer bass or explosive dynamics, regardless of the model size—if that's your primary listening predilection, I suspect you need to check out the Pass X-series). While I observed a small level of haze (again, mosfets do have characteristic qualities), I never felt deprived of any musical information, and I suspect any absolute loss of clarity will likely never be noticed by the majority of audiophiles—and I'm confident in saying it will have no adverse impact on the musical message the amps are trying to deliver. Sonically, even in a perfect world, there is little lost, little given up, and little more one could hope for than what the XA.5 series from Pass Labs deliver.

You can read the full review here.