When I try to work out modifications to amps & DAC's I do much better when I'm able to relax during listening sessions. Doing A/B comparisons even sighted for me puts me in the wrong mindset to determine differences & whether they are beneficial or not. It typically takes me at least 2 or 3 songs to get in that relaxed state where I can start to pick up on subtleties that make the difference in what I want to do to improve the sound. However once I'm done making all the needed changes the difference is obvious even to the uninitiated yet measures within acceptable variance to what you would expect from a stock unit with exception of slightly improved frequency response at the very bottom of the frequency response plot. I'm talking only a few hundredths of a decibel flatter @ 20hz. Not an audible difference from a frequency response perspective. Distortion is still well below -100db, well below audibility. Everything just sounds much clearer especially background instruments & voices when done.