At the risk of sounding like a Sound Scientist ....
With the different sensitivities of the headphones, the amps, the amp inputs, the +6db switch, all conspiring to ensure that each listen was at a different volume, was there any time you guys were confident you were comparing anything with anything at exactly the the same volume? By using a db meter for example.
For me, volume mismatch is the arch enemy of comparison tests, particularly in an A/B rapid(ish) switch situation. So if the +6db option is as the name implies (6db extra gain) then of course it's going to sound more dynamic etc. It's 6db louder!
I'm not saying that informal comparisons don't have their place (I do it all the time). Just that in this case, the scope for misinterpretation seems particularly high.
Edited by TheAttorney - 7/25/12 at 12:35pm