DAC Configuration

This DAC was purchased from Taobao
Thanks and appreciation to Timber for this recommendation and his discerning ears.

What is a DAC?

A DAC is a Digital-to-Analog Converter. A DAC [Digital-to-Analog Converter] is an electronic processor inside digital media players that converts digital audio information (comprised of series of 0s and 1s) into an analog audio signal that can be sent to headphones, or better yet, a headphone amp.

This unbranded DAC has the following configuration.

220V supply
Duo WM8741 decoder chip
TOSlink (aka Optical cable input)
Coaxial input
USB installed XMOS chip module
RCA output

On/Off switch

The AK4113 is a 24-bit stereo digital audio receiver that supports sampling rates up to 216kHz. The channel status bits decoder supports both consumer and professional modes. The AK4113 automatically detects non-PCM bit streams such as Dolby Digital, MPEG etc. When combined with the multi channel codec (AK4626 or AK4628), the two chips provide a system solution for Dolby Digital applications. Control of AK4113 is achieved though a µP or pin strapping (parallel mode). It is packaged in a space-saving 30-pin VSOP.
Some of the photos on their web are not updated.

The XMOS module is located on bottom right (small PCB)

Mainboard Rear View

LED selector indicator lamps

AKM AK4113VF 

Asahi Kasei Microdevices (AKM) AK4113VF Clock 

You will find the updated ones here.

Investigative findings

XMOS Chip

Close up of the XMOS module

This XMOS module has another PCB backing to hide the connectors.

What is XMOS?

XMOS is a fabless semiconductor company that develops intelligent multicore microcontrollers that execute multiple real-time tasks, DSP, and control flow concurrently, with entirely predictable behavior.

The company is funded by Amadeus Capital Partners, DFJ Esprit, and Foundation Capital, and strategic investors Robert Bosch Venture Capital GmbH, Huawei Technologies, and Xilinx Inc.

The XMOS module allows digitised music to stream via usb without the need of drivers on the Macbook Pro running OS X 10.11.2 El Capitan. Moreover, music players like VOX can recognise and play through the DAC.

XMOS 8U6C5

8U6C5 / SK1511SU1 / P1YG68.00

The stamping provides information that the DAC chip is commercial grade.


iOS and XMOS
I am interested to know if my iphone 6 with iOS 9 can be accessed by the USB XMOS via the Apple Lightning to USB Camera Adapter.

Lightning to USB Camera Adapter

The role of the iphone is to pull the digital music file from the NAS and relay the digital music into the DAC. The iphone is to replace role of the Macbook Pro.

Schematics
NAS >> Router >> Iphone >> DAC >> Amplifier >> Headphone

NAS: Qnap TS-269L
Iphone runs the Qfile app that transmits the FLAC files to the DAC via USB.

Amplifier is connected via RCA cables.