Can I connect multiple sources to an external DAC

Depends on the DAC.  Some have multiple inputs with a front panel switch to choose the source.  Most commonly you'd see a coax input, an optical input and a USB input with a switch to choose between them.  If your CD and Node are capable of different type outputs this would solve your problem.  There are fewer DACs that have two coax or two opticals inputs. If your sources only have one output and both are of the same type you'll need one of these DACs which will limit your options.  You'll need to figure out your needs and then research the market for what's available.

Depends on your DAC. 

Thank you. In shopping around, I could see the multiple inputs but didn't see a way to switch. Good to know that it exists. Both sources have optical and coax.

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.

My Pure Audio Lotus DAC5 has 7 inputs. 2 coax, 2 optical, 1 USB, 1 11S/DSD, and 1 AES/EBU. Selection is by remote. That would seem to cover just about everything anyone would need. Oh and also it's a great DAC. It did more for my set up than Denafrips Pontus, MHTD Orchid or the Topping D90SE.

I have a simple solution to your problem and it will cost you $26. I was always running into the same problem as I have multiple Sony mega storage CD units I use as transport.

Just a couple weeks ago I decided I am NOT buying anymore DAC units. In addition, I am not going to spend a ton of money on a DAC that has a couple extra optical ports. It would seem to me there should be a whole row of them on ANY half decent unit. 

But anyway... Here you go. Hit Amazon, look up a LINKFOR digital toslink optical 4x1 switch. Btw.. LINKFOR is the brand new, that is not a typo..

So easy it is stupid! There are 4 optical inputs and (amazingly) 1 output. Just plug up anything you need to run to your external DAC , use the remote to turn this little unit on, select which port you need and wow- problem solved.   I was able to free up a couple of DACS that I wasted money on for some other projects. I am running 3 CD decks and a streamer thru this thing and it works perfectly!!! Gee, all for $26 bucks and I love it. http://LiNKFOR Digital Toslink Optical 4x1 Switch with 3ft Optical

All Denafrips DACs accept multiple inputs.

The Ares accepts USB, optical, co-ax, and I2S. The Pontus II and Venus II add BNC co-ax and AES/EBU. The Terminators add RJ45 I2S

hope that helps

To over-clarify…you’ll no longer use your preamp to select digital sources. The only source will be your DAC (and your phono preamp if you’re spinning records).  All digital sources will be selected via the DAC.

My Bryston BDA-3 DAC has ten inputs, selectable buttons on the front panel or the remote.  Has balanced and RCA outputs. Stereophile Class A (not that that means a thing!).  Not sure how much you're looking to spend...the BDA is $4k.

Regards,

barts

Sure. I have a Node N130 and 2 different Transports running into my Pontus ll.  And there’s room for more.

Thank you all. Time for some more research and hopefully some auditioning.

Let's start by defining what your problem is first (and then you can correct me if I m wrong!) 

You have 2 digital sources and you want to improve the sound quality of both by adding an external DAC. otherwise there would be no need for adding an external DAC right?

if you buy a DAC that accepts 2 inputs (mine accepts Optical and Coax, but it does not matter ) the problem is solved that is because you are not going to be listening to 2 sources simultaneously. Just turn off the source that you are not going to listen to each listening session. Your DAC will lock to the incoming signal and will convert that one feeding the analogue signal to the preamp.

If you have more than 2 digital sources then a switching box such as the LINKFOR suggested above is the solution. 

Exactly, sound improvement and normalization if I can call it that. I'd like both sources to have the same quality. From all the comments, it seems like there are many options for external DACs that can switch between sources. 

Correct -- both the Topping and Schiit examples I gave have a button on the front panel to switch between inputs.  There are some DACs that "autoswitch" based on which input is providing a signal. In your case, that could be confusing to the DAC if both sources were playing at the same time.

  I think it's all been covered, but it doesn't matter that the DAC gas only one output to the preamp.  You can connect multiple digital sources to a DAC, but only play one of them at a time