The SPDIF DAC has been around since 2005
and there are few reviews on 6moons, most recent one here: http://www.6moons.com/audioreviews/a…e5/system.html
The USB DAC was introduced a bit later and it’s basically same circuit with
exception of input interface which converts USB signal directly to I2S.
![](https://audiosector.com/wp-content/uploads/2019/01/usb-dac-1-1.jpg)
![](https://audiosector.com/wp-content/uploads/2019/01/usb-dac-2-1.jpg)
The DAC circuit board fits inside 2 x 3 inch aluminum tubing.
![](https://audiosector.com/wp-content/uploads/2019/01/usb-dac-3-1.jpg)
![](https://audiosector.com/wp-content/uploads/2019/01/usb-dac-4-1.jpg)
I liked the DAC in the open though and over the years few different versions of such assembly circulated.
![](https://audiosector.com/wp-content/uploads/2019/01/usb-dac-5-1.jpg)
![](https://audiosector.com/wp-content/uploads/2019/01/usb-dac-6-1.jpg)
![](https://audiosector.com/wp-content/uploads/2019/01/usb-dac-7.jpg)
![](https://audiosector.com/wp-content/uploads/2019/01/usb-dac-8.jpg)