From Aurender's website: 

The Aurender X725 is an all-in-one DAC, preamplifier and power amplifier designed to simplify the task of  configuring and setting up a High-Resolution audio system. As the DAC, preamplifier and power amplifier are  conveniently built in, all you need to do is to connect the speakers to the Aurender X725. Simply have a USB  cable, power cord, Ethernet cable and a pair of speaker cables ready and you are all set! 

An audio system designed around the Aurender X725 and X100 music player will use fewer cables and fewer audio components than a traditional analog based audio system, and can be set up much more quickly and easily. The Aurender X725 is ideal for music lovers who don't have the patience or space for all the "Audiophile clutter" but want to maintain the sound quality.

Main Features

• Elegant machined aluminum chassis

• Designed for quiet operation

• USB interface for high quality audio

• Auxiliary optical SPDIF input (useful for connecting additional audio sources, including CD players.)

• Supports all major high resolution audio formats

• Plays up to 24/192kHz, DSD64/128 in native mode

• Power rating : 100W per channel at 8 ohms, THD+N 0.01%

• IR remote controller

The digital audio signal received to the USB audio input of X725 from the X100 or N100 is converted to an analog signal by the internal DAC.  The preamplifier section controls volume and source selection, and the power amplifier amplifies the audio signal to power the speakers. And, the fun iPad or Android app controls all!