First let me say that I have used the search function extensively and haven't found an answer to my dilemma. The only amp that I have is a Pico Slim, as I never thought I would want any high impedance full size cans. Well, that has changed. I currently have the money for HD600, but not a powerful amp to go with it. I was able to demo the HD558, which is substantially cheaper and has about 1/6 the imprudence. My question is if it's even worth it to shell out the money for the HD600 if the only amp I have isn't capable of unlocking its full potential. Basically, what's better: a properly-driven HD558 or an underpowered HD600?