The E7 USB DAC Headphone Amplifier from Fiio is a compact headphone amplifier that provides analog and digital input and output for high-quality listening. It offers USB audio decoding and output for PC, functioning as an external USB sound card. It has a USB receiver from Texas Instruments, a Wolfson digital-to-analog converter, and an ADI amplifier to offer exceptional audio quality with low distortion and strong output.
The amplifier has a standard 3.5mm line input for compatibility with a variety of music players, laptops, and other devices. It also has a pair of 3.5mm outputs so you can connect 2 pairs of headphones or earbuds simultaneously. The amp has a digital volume control for excellent precision and balance. There is also a built-in EQ that provides 3 levels of Bass Boost.
The E7 has an anodized aluminum satin finish case for looks, durability, and minimal weight. It also has a dual-color OLED display for clear readouts. The integrated rechargeable Li-ion battery provides up to 80 hours of continuous operation so you can listen for days without recharging.
The E7 has a number of user-selectable functions, including a selectable USB charging function to prolong battery life, as well as a definable startup volume memory and maximum volume limiter to help prevent hearing damage due to loud volume levels. There is an automatic keylock feature to prevent accidental changes, plus a sleep timer function that's ideal for use at night.
The Fiio E9 Desktop Headphone Amplifier with E7 Dock is designed to work with the Fiio E7 USB DAC Headphone Amplifier and USB soundcard. It features dual-channel power outputs for both 1/4" and 1/8" headphone plugs, as well as an additional RCA L/R audio output, USB interface and line input. The amplifier features a Texas Instruments main power amp integrated circuit with a low noise level, low distortion and a high conversion rate. The E9 is cleverly designed with an E7 dock for using the line out signal from the Fiio E7 docking port. This provides better sound quality and makes the amp able to drive high impedance or low sensitivity headphones - giving you the clarity and punch to make your music sound alive and vibrant. Plus, it lets you charge and sync the E7 with your computer as well. The E9 even has a Low/High gain section switch, LED power indicator and a built-in power converter to meet the demands of high dynamic signal processing.