I am assuming that was Sam Tellig that you quoted. First, he is making a totally "out-of-hand" statement, based on the measurements of a single ended tube amp design. This is obvious, as he refers to "adding negative feedback" as some kind of fix for distortion. It was known more than 25 years ago that negative feedback is NOT a fix for distortion in a real world environment, but only on the steady-tone measurement bench. No really good single ended tube designs that I am aware of, use any negative feedback in the circuit. Their "measured" distortion shows up as higher than SS on the bench, but not in the listening room. It is really sad that a person that writes for an audiophile publication is so ignorant and misinformed. Perhaps now you see why some of us have such little respect for the reviewers in the audio rags. Not all single ended tube designs are great, or even good. But the good ones are capable of doing the job as well or better than any amp out there. No audiophile in his right mind would spend $10k on a single ended tube amp that had so much distortion, that he couldn't listen to it, and no company would expect to sell such an amp. In fact, there are a good number of "hardcore" audiophiles that wouldn't use anything but a single ended tube amp, because they feel that only SET is capable of meeting their stringent sonic requirements. To sum up, a SET does not have higher "real world" distortion, and may actually have less than other amps, measurements notwithstanding.