Hi

The only device that connects (I assume you mean by cable) to the Arc is a TV via HDMI.

You cannot connect a 3rd party device such as the Onkyo DAP dp-s1 to a Sonos Arc. I’m not familiar with the player but if it is AirPlay 2 capable you could possibly stream to the Arc as long as the codec is acceptable. 

Thanks AjTrek1

Maybe I study the Onkyo DAP Dp-s1 manual again, if can’t connect ( even though by other method) to the Arc, I can copy the song to iPhone and play it to the Arc via Airplay . 
 

Thanks for your answer again