Can I connect multiple sources to an external DAC

Two examples of DACs with multiple inputs (I've owned both.) At the relatively inexpensive end, a Topping E-30 has coax, optical and USB inputs which are switchable from a front button. The Schiit Bifrost at $800 also has these inputs which are switchable from a front panel button. Other Schiit and Topping Dacs can also do this, but check the details before you buy. 

Thank you. The Bifrost is a contender for sure.

The Denafrips Ares II has 1 USB, 2 coax, and 2 optical

inputs with selection on the front panel. This was a major consideration for me when I bought it. I don't know why more DACs don't offer multiple coax or optical inputs. Most people are running at least a streamer and a cd player.

I have a Bluesound Node that's connected to a Topping D90SE DAC through USB. The Bluesound recognises the DAC, which can be selected. 

I have two CD players connected to the DAC, one with Optical and the other with Coax. 

The desired input can be selected with the Topping's remote.
 

Equipment connected to my Gustard X26 PRO dac:

- Node via USB

- Digital FM tuner via coax

- Jay's cdt2-mk3 CD transport via I2s and also via XLR for overly bright albums. 

So yes, that's what good dacs are for, multiple connectivity.