I'm no EE, but dynamic headphones (i.e. 99.5% of them) have a generally high impedance (relative to earphones) and require a higher voltage to operate. Add to t

I'm no EE, but dynamic headphones (i.e. 99.5% of them) have a generally high impedance (relative to earphones) and require a higher voltage to operate. Add to that the fact that they are a mostly inductive load, and you get the recipe for a hard to drive device, that requires a high voltage paired with an strong inductive kickback