I bought the Quiet Comfort 25's from Bose, last year and used them for about two months before selling them. No DAC, DAP, or any special kind of amp. I plugged them in the headphone jack of my cellphone and listened to music.    The first thing I noticed, outside of Best Buy, walking back home with the headphones on my head, really pissed me off. I don't know if I had a damaged product, or if I didn't wear the headphones properly, but whenever I walked a step, the music would  cut off for a second.  That was a huge problem.   Secondly...