Originally Posted by camaker
If that is the case, what type of music should I use to evaluate sound quality differences between the two set ups? I have a wide variety, the listed genre is just my most commonly listened to.
This is where things can get very confusing for a relative newbie. I now have back to back posts telling me that a)Lossless files and higher quality recordings are the way to go and b)With my music the sampling quality doesn't matter. Any tie breaking votes or alternate views out there?
The main point of having a DAC/AMP is to be able to drive headphones with high impedance at high volume which the iphone/ipod can't do, not dramatically change the way things sound.
The main advantage you have now is that you are able to drive your headphones at a decent volume and hear all the nuances in the music without concentrating like buddhist monk.
If you were expecting a huge in-your-face difference then you can only be disappointed. In my experience the only component that really makes a huge difference in sound quality is the headphones themselves, the dac/amp is only there to help them achieve their potential.
As for the style of music to test the audio quality, try something with vocals, real recorded instruments and high dynamic range. Search "loudness war" on google to learn how to identify music that has dynamic range and which one is plain noise. (badly mastered music will sound crap no matter what you do)