As mentioned, depends on your playback source. I have a few DACs that I have played around with the Atom while using the HD800. I also occasionally connect my handphone a LG G6 Quad to the Atom with a RCA adaptor. They all sound adequately pleasing to my ears. I tried connecting my friend's handphone, an older Samsung S5. It didn't sound adequate. I didn't try the line-in option on the Atom, so perhaps it might work well/better with that. Suggestion would be to try with whatever source you have to plug into the Atom first before launching into a DAC. And forgot to add, the Atom drives the HD800 very well indeed.