Review on 🔌 Douk Audio USB Converter XMOS XU208 Digital Interface Optical Coaxial DOP SPDIF Adapter DSD64 PCM192Khz by Rick Ross

The sound quality of this box is really excellent. I'm using it to transfer 24/192 PCM audio from a Windows tablet to a Benchmark DAC1 using a glass optical cable. This particular DAC is very sensitive to the quality of the input signal. I used the SMAKN CM6631 audio interface, but it seemed to me that too much computer action was heard over it - in particular, the beginning of each song was brighter and forward than the rest, because the player used the computer a lot during this time. So I decided to try this box and this problem disappeared. Now the sound is just as good. I thought the picture was a bit smaller so I tried some changes that will make the Smakn box sound better - a shorter USB cable and external power supply. I initially set up the douk box using the USB OTG cable that came with the computer and the long USB cable that came with the douk. The OTG cable features an external power input to avoid draining the tablet battery to power USB devices. This improved the sound, but only slightly. Shutting down the computer (with an OTG cable, both PSUs are actually connected) and using a short cable did the job. Unfortunately, the Douk designers didn't externally power their box. The Smakn box has a separate power input port and a switch to select external power or USB power, making this very easy. For this box I had to connect my own USB port. I made a USB cable about an inch and a half long with a micro USB connector on each end and a power cord coming out of the side. The computer side is connected for OTG (pin 4 connected to pin 5) and no power (pin 1 not connected). On the side of the douk box, power (pin 1+) and ground (pin 5 minus) are connected to an external power wire. The rest connect well. Using this "cable" and an external linear power supply makes the sound really great for me. The images are now a normal size and the depth and clarity is as good as I've ever heard. I really wish the designers would make this easier by building a power connector into the device. If you try this I really recommend using a linear power supply. Most power supplies today switch and generate a lot of electrical noise. Line sources use a transformer instead and generate less noise. I'm using C-TON PW2-5 (5V 300mA linear $16 Digi-Key). Sounds very good. If your DAC has better jitter tolerance than mine, it might not matter, but it's worth a try. USB port of the computer and use a standard adapter (any type of connector) to replace the cable. USB cables introduce signal jitter and also pick up electrical noise, so less is more and nothing beats (just a short adapter).