I'll try to keep this short and to the point. I'm looking into purchasing a headphone amp (Lambert Play it by Ear) and slowly upgrading the rest of my gear over the next year. I currently have two sets of headphones I use: Shure SE425's for office, and Bose QC15's for when I travel. Output comes from Macbook Pro Retina, Iphone, and PC w/ soundcard at work. Is my money wasted on the amp or will I notice a difference with the amp? Should I be investing in better headphones prior to this? I notice a significant improvement from my work PC to that of my iPhone already for instance (less roll off of lows). I appreciate your opinions on the matter, and thanks!