Interesting article on SET amps

[E-Stat]

In fairness to Elliott, his article isn't just a series of assertions. It's fairly long 28 pages wherein he argues from theory, simulation modelling, and constructed test examples.

Mostly theory and computer simulations evaluating numbers. Not listening to real products reproducing real music. Which is where I find that real designers have a decided edge. Let's look at another one of Elliott's "assertions":

"Contrary to audiophile myth, feedback doesn't cause higher order distortion, it them to be more easily measured."

Pass would just smile since he has proven otherwise. While I don't believe for a minute he's the only guy out there doing good stuff, I think he is the best communicator of the concepts. Read his document on distortion and in particular the story of a real world amplifier he built using variable amounts of NFB which empirically counters Elliott's speculations. As did my two minute test measuring the results of connecting two cables via a Y adapter.

Pass on the complex world of distortion

I'm not sure I follow you; are you talking about the capacitance in the cables? If so, there would be a difference of course.

He is asserting that his test can determine whether or not you can hear the difference between two different cables possessing different characteristics.

The test fails to work miserably, however, because the methodology ends up blending the metrics of the two cables such that you are not comparing one cable by itself to another by itself. You hear the combined results in input A and you hear the same combined results in input B. In reality, you're not comparing anything. You're hearing the same result in either input. It is not at all like connecting one set of cables - then disconnecting them and connecting the other set of cables. He doesn't even bother to validate his theory with the simple test I performed. No wonder he thinks all "well designed cables" sound the same. He's not comparing anything!

ABX testing using a box fails for the same reasons. In order to avoid horrible switching transients, you must necessary share the grounds. So you are blending cable characteristics or even feedback loops between separate amplifiers. It was Frank Van Alstine that first made me aware of the fallacy behind the use of ABX boxes.

Do you remember Skeptic/Soundmind? He had a similar "shunt test" whereby he contends you can determine whether or not a cable is absolutely perfect by switching it in or out of a tape monitor loop. He has no comprehension of the logical fallacies involved with his set of assumptions.

Too many guys with good intentions arrive at false conclusions due to the set of unproven assumptions they make with their test methodology. Which is why seasoned ears prefer simpler circuits like SETs to complex switching designs that measure far better.