If you believe in the DBT's that say that MP3's sound the same as CD, or that a 1970's solid state amp is state of the art because DBT's can't show any difference, you are not an objectivist. You are a fool.
Your biases are showing.
MP3? All mp3 is the same? 98 then I guess all would agree with you. Higher rates not so much (or so they say). In any case you have not even defined the 'test'.
What I find more interesting is how this slipped past everybody without comment.
Blind testing does not overcome biases. There are some which can not be overcome by blind testing - e.g. that all amps sound the same. If you subject 1,000 people with this belief to a blind test, your result will be: all amps sound the same.
Why then would you test that group? After all it is not they making the claim of 'differences in sound' between amps. If you felt the need to test that group, how about sticking a honking great resistor and or cap on the output of one of the amps, something that would definitely change the sound. Would they still claim to hear no difference? (this would fall under the category of 'selecting the group', those that show an ability to hear differences.) I doubt people would deny a difference like that simply to maintain their position.
Successively reduce those components (to zero eventually), and BOTH groups would have to state the point at which no difference could be detected. (or find that even with those parts removed a difference was still heard)
Anyways, the point is to test the claimants surely?