I bought the headphone amplifier actually for my new Beyerdynamic DT990, but was compared to the sound card of my notebook (Acer Aspire V5 model of the middle class) do not hear much of a difference from my smartphone, the device is not recognized, so I have the FiiO returned. Whoever thinks to have particularly sensitive ears (although I cut the hearing test every time outstanding from, but seis drum) attempt may dare again, I think these days have reasonably modern computers and mobile devices sufficient power and detail for higher-priced headphones. Since this does not change in the assets of the amplifier, but makes it unnecessary for me, I vergeebe a neutral rating of 3 stars.
