I have to say that much of what's being here doesn't make sense. People are willing to attack Brian because he likes to adjust his tolerances to a very high degree, which people argue is immeaserable although apparently Brian is of the opposite opinion. Yet those very same people espouse different amplifiers and use of power cords, interconnects, etc., none of which produces any measureable deviation whatsoever. The very same people laughing at Brian for his apparently ridiculous beliefs about tolerances for filters have the same unsupportable beliefs regarding break in of cords, the "helpful" use of power cords, amplifiers have similar THD and intermodulation distortion readings sounding different, interconnects with no measureable differences, etc.
Don't know who you're talking about here... I don't waste my time with power cords for instance... But some of the things you mention can make an audible difference and are in fact measureable. Even power cords if you have a badly designed psu.
You can't have it both ways -- either you believe that mathematics and measurements solve these problems, or you don't. I can't see how 2 percent tolerance on filters doesn't matter but amps that measure exactly the same sound different.
2 percent? Someone whose name I apparently shouldn't be mentioning, was talking about trimming the value in steps of 0.01 percent... Reread
this post and please comment if something is wrong with my conclusion that the audiblity of tolerances discussed there is dog poo and probably just marketing.
