I recommend Schiit Eitr. Converts usb to coaxial and optical and improved sound quality, in my opinion. Schiit currently has closeout units on their product page at a good price.
Thank you. I have seen it, but was somewhat demotivated by its measurements on Audiosciencereview (I am not associated with the website, just landed there from Google search).
Will look for more info.
UPD. Oops, it doesn't support optical output, only coaxial.