Audiophilepure

http://goo.gl/hPwvQu Read Here

” First I would like to talk about power and amping, these do require a good headphone amplifier, they are not suitable for using with a standard portable source. Even thought they only have 48Ohm impedance, the sensitivity is only 93dB/mW, I had to put the gain on my iFi iCan up to +10 for these, and it drives them with ease like that. Also note these use Planar magnetic drivers, not your usual dynamic drivers, by design they do prefer more powerful amplifiers.”