First off, love the site.  I have already wasted hours reading through everything.
Second, my apologies if this has been broached before elsewhere.

Have you guys considered doing some amplifier measurements?

I have always had issues discerning the difference between 2 well implemented amplifiers, most likely due to the low levels at which I tend to listen.  Despite that, claims seem to abound about how much Amp A improves Headphone X over Amp B.

I was thinking that if this indeed true, shouldn't it be able to be measured?  Is the problem that the difference might be audible to a listener but below the threshold of the standard error when measuring the headphone's response?

Anyways I would assume that with the same source and headphones, one could do a set of measurements with 2 different amplifiers and then compare the resultant frequency response, thd, etc.  Maybe also do it at different volume levels.

What do you guys think?  Am I missing something obvious?