So what's the problem with e6? Not enough power?

I thought about getting a fiiO so I can use them with my phone when travelling, but they only sell the E06 fujiyama so would that be enough? I also thought about getting samson s-amp to home. Edit. Forgot that you have e6, so I'll change my question, how's the e6 been so far? Don't expect much...

So what kind of amp would be enough? Dt-770's are 250 ohm and 100 mW and all the amps are usually displayed X mW to 32 ohm. thanks