<p>Description from FIIO:</p>
<p>FiiO E7 portable headphone amplifier with USB audio decoder (DAC). This   product is designed to replace PC onboard soundcard that do not have   enough output power for higher-end headphone. With USB audio decoding,   amplification and audio output, E7 can serve as both a professional   headphone amplifier as well as an external USB soundcard.</p>
<div><strong>Main Features?</strong></div>
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<div>?USB audio decoding and output for PC, functioning as a high   quality external USB soundcard*;</div>
<div>?Texas Instruments&rsquo; PCM2706 serves as USB receiver. For better   sound quality, a Wolfson WM8740 serves as digital-to-analog convertor   (DAC), pairing with a high performance operational amplifier from ADI   for the DAC circuit;</div>
<div>?Build-in headphone amplifier utilizing AD8692 and Texas   Instruments&rsquo; TPA6130A as pre- and power-amp for high performance, good   resolution, low distortion, and powerful output;</div>
<div>?Standard 3.5mm stereo line-in jack for portable amplification with   conventional audio source;</div>
<div>?Dual 3.5mm headphone output jack. Convenient design makes it easy   to share music between two listeners;</div>
<div>?World&rsquo;s first portable headphone amplifier with dual colors OLED   display;</div>
<div>?Easy to use digital volume control function with great precision   and channel balance;</div>
<div>?Build-in EQ for 3 levels of Bass Boost;</div>
<div>?Build-in rechargeable 1050 mAH Li-ion battery for 80 hours of   continuous operation**;</div>
<div>?Specialized dock for connecting E9*** to experience an even higher   performance;</div>
<div>?Quality anodized aluminum satin finish case design, small and   compact, ideal to be wrapped together with digital audio player;</div>
<div>?User selectable USB charging function to help prolong battery   lifespan and lower distortion from power supply circuit;</div>
<div>?User definable startup volume memory and maximum volume limiter to   protect user from hearing damage due to loud volume;</div>
<div>?Automatic keylock feature;</div>
<div>?User definable sleep timer function and total runtime display****.</div>
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<div>* This model supports driverless plug and play on   Windows XP, Windows 2000, Vista, Windows 7, and various Mac OS.</div>
<div>** Full battery charge via computer USB port after   200 minutes and capable of 80 hours of continuous operation, tested   under laboratory condition for evaluative purpose only.</div>
<div>*** E9 is a desktop amplifier with greater output,   better performance and an integrated E7 specified dock connector. With   the dock, E7 can easily establish a line-out connection with E9 and   transform both together into a high performance desktop amp with USB   decoding function, capable of PC connection and recharging functions,   etc.</div>
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<div>**** Total system runtime will accumulate from the   first use. It will be reset to zero after either reset button is   pressed, reloading default setting, or when the battery depleted</div>
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