I think you're missing the fundamental point of the article, which is that no-one can tell the difference between various amp manufacturers, high-res vs standard audio, expensive vs cheap cables etc.
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Regarding cables and the like, this is true , such items are pure fraud. No doubt about it.
Regarding amps , high res vs standard , this is not true at all.
If you read the AES papers properly and look at the data breakdowns where available you will see that there are always individuals that get either 100% or a statistically significant result.
What these papers claim from the overall results is that " on average" and as a a group , the people under test couldnt tell the difference!
That is a hugely important difference here , in no case does any paper say that no one can tell the difference and it is very wrong to take from them that they do say that!
Also regarding amps and dacs, the statement that any properly designed dacs or properly designed amplifiers would have no audible difference between them would probably be true if there was a standard or even general consensus that designers should work too, but there isnt and never has been in the audio industry.
Properly designed amps or dacs are therefore mythical entities! They dont exist, and I couldn,t imagine that anyone with an electronics background could ever make the claim that they could be the same when we are talking about an industry with essentially no standards and no rules to adhere to.
Add to that the modern practice of custom chipsets or circuitry being deliberately introduced into the signal chain for that "manufacturer" sound and you can easily see why most dacs and amps from most manufacturers do actually sound different.