You will need some kind of DAC. Although not common there are a few tube pre-amps w on-board DAC, including Monarchy M24, Jolida (several) and Peachtree Nova. There are undoubtedly others, or you could go w a separate tube pre-amp and DAC.
I have used a Mac Mini into a Bryston BDA-1 DAC with a Jolida tube pre and now a Aric Audio tube pre. I believe using a tube pre will benefit your system. Improvements in soundstage width and depth, immage specificity, and timbre.