Regarding burn-in. When I bought my brand new K702s three years ago I just out of curiosity used my notebook as a source/amp. Phones had harsh trebles and totally missing bass. When I used them with my DAC and C2C amp it was much better but still not as good as I expected. Playing a pink noise thru them for one week 24/7 at decent volume level to relax their drivers improved their sound a lot.
Two weeks ago, just before ordering my new setup I used my notebook as a source/amp again and I was really surprised how good these phones sound now. It is not a magic, their drivers need to be relaxed first.
I was also searching for better/perfect sound. I was hoping my previous setup will last forever. It was not cheap, spent 1100USD just for DAC and HeadAmp + some cables + K702 + HiFace. I loved the sound but felt more and more often that something is missing. My favorite PCM1704UK chips are already obsolete and their price went up - 90USD/ea. That was why I decided to make another step in my quest for perfect sound and I bought Reference 10.32 while it is still produced - what a huge step up in sound quality. Makes me curious how Master 7 + Master 8 (Audio GD top combo) sound.
At the moment I am in love with its sound and except new phones (HD800) I don't see many possibilities what to buy next because at this level of sound quality you need to invest lots of money to get just slightly closer to the music or to perfect sound. The bad thing is the better gear you have the less music you can listen to as LoudnessWar and bad mastering ruined most of newer records. But it is another story.
Enjoy your K702, I am sure you will love them as much as I love mine ;-)
Edited by PiNa.cz - 1/23/13 at 2:29pm