SurgicalYes you can. The D50 has RCA-output. You can simply use an RCA-to-3.5mm cable to connect to the Aux-input on the back of your XD-05. Doing so will bypass the internal DAC of the XD-05 and you will be using the XD-05 only for amplification.
The XD-05 is nice sounding dac/amp on its own but unless you've upgraded it with the Burson v5i opamp I would consider finding a different amp to pair with the D50 in this drop. The v5i upgrade is about $60.
https://www.bursonaudio.com/xduoo-xd-05-with-burson-v5i-opamp/
KC-130Oh wow, I actually have an xDuoo XD-05 (with Burson v5i installed) myself and never thought about doing this XD-05+ D50
combo. How do you connect an optical from a computer to this D50?
JoeyG13If you have an iMac you can use the 3.5mm audio out. That port doubles as an optical output. If you have a PC you'll need to consult the bones... or just use USB output.
KC-130Yeah I have a custom-built PC Tower. I'm probably going to go with USB, then. Any suggestion on type of RCA to 3.5mm cable between the D50 and the XD-05? I'm also listening on the Fostex TX-H00