There is a trick you can try to use it in an optimum way. That will only work, if it works at all, when you use the USB input with your PC (laptop/desktop) and the analog inputs may become your preamp output.
That is the way my Xduoo works and it is a very nice surprise to me as it sounds fantastic with my power amp. If that does not work, then the next best option is to use the headphone jack. You obviously will then need a mini jack to RCA cable. Is your Denon an integrated or power amp?