Getting recommendations on headfi has been great. But there is a lot more i have yet to learn. Please teach me to fish for myself! Is there a way to know how much power I need to drive the ER4S as well as it can be driven? Is there a point where it maxes out? I'm not talking which amps synergize well with the ER4S but what kind of numbers would I be looking for as far as power output. And here, I'm going to show how much I don't know. Is it how many watts I need? or voltage swing? (Its impedance is 100ohms if that helps...) Thanks for any help!