The E17 USB DAC Headphone Amplifier from Fiio is a compact amplifier that improves the sound quality of practically any portable audio source. The amplifier has a standard mini USB interface that can connect to a computer to accept digital audio and also to charge the amplifier's battery. Standard 3.5mm line and S/PDIF inputs let you connect analog and digital sound sources, such as MP3 players, smartphones, tablets, and more. The 3.5mm stereo headphone jack accepts the vast majority of headphones and earphones.
The amplifier offers gain, balance, and tone controls so you can adjust your music to suit your tastes. The 18-pin docking interface lets you connect the amp to an L7 line out cable and E9 desktop amp (available separately) for further versatility. A bright OLED display shows vital operating information. The built-in Li-ion battery offers up to 15 hours of operating time, and recharges in just 3.5 hours.