Best quality connection from Network Streamer (BluSound Node II) to Preamp (MC C2700)

You have to love when you ask a simple question here how quickly it turns into an out of control freight train. You ask what is the better option for audio out and by a short end of replies you are being told to spend 5k on a new streamer. Try all your options and go by what your ears tell you. Don’t just listen for five minutes. Try to listen to each for one to two hours and see if you experience any listening fatigue. To me that is very important. What good is a very resolving detailed sound that you can only listen to for short time and feels like razor blades in your ears. Enjoy the music!

I’ll agree as well regarding a stand alone DAC. For now I’d say the digital coax should be your best result. I had the Bluesound and that was my choice of connection.  
I have a Gustard DAC now.  I see a lot of posts about the Denafrips Pontus 12th. Has anyone compared to to the Gustard 26 pro.  I may be looking for a new DAC. 

I have a C2700 with the DAC2 module. Started off streaming with a Mac Mini (Roon core) and recently upgraded to a Lumin U2 Mini. Really big difference in sound quality. I tried Coaxial and USB cables between the Lumin and the C2700. The USB cable sounded much better to me. I also don’t know how much of the Lumin streamer improvement might be because of the network connection. 

That DAC2 module is decent. I have a Schiit Modi+ dac that I use for my Mac Mini. I was curious if it would sound better and the DAC2 module sounds better. 
 

I do plan on upgrading my DAC down the road. The DAC2 is convenient, but now that I have the Lumin, I really need a Dac to take advantage of the better streamer. 

I agree with @riie .  Upgrade your streamer to something like Bricasti M5.

So you spent 10k on a preamp and 500 on a streamer. Before worrying about the quality of the connection I would for sure upgrade the streamer.

As previously pointed out, the Node 2 does not have USB output. If you output via coaxial or TOSLINK you will bypass the Node's internal DAC.  You will want to use fixed (not variable) output setting.

You can connect the coaxial and analog RCA outputs simultaneously and switch between the two and decide which you prefer.  The Node will output both simultaneously.

I have a Node 2i with a Denafrips Ares II DAC.  The DAC in the Node isn't bad, but I have no experience with your preamp.  But based on its price, I would hope it would have a better DAC than a $600 streamer/DAC combo.

Had similar setup for awhile. 2700 and newer Node with USB out. My ears found the USB connection to be the best sounding to me. The McIntosh DA2 DAC definitely sounded better than the Node’s DAC. I later borrowed an older Naim DAC-V1 from a friend, and the improvement over both the Node and the DA2 DACs was very easy to hear.

It is correct that the Node II does not have an USB out. So chosing coax over toslink would be an easy pick for me.

I have the DA2 in my integrated and find it to be a good place to start. Which interface to use is a tough one. I would eliminate Toslink. That leaves coax and USB. Buy from a source with a great return policy and buy equally priced coax and USB and let them fight it out. Lots of threads on bang for the buck cables.

I have been pleased with the coaxial RCA output into my dac.  

I agree with jjss49 and carlsbad2. I have a Node 2 and used the internal DAC, then moved to a Schiit Bifrost DAC, then to a Bifrost 2 DAC, then to a Denafrips Pontus 12th DAC and it was an uptick in sound performance with each step. I also upgraded the power supply in the Node.

Neither DAC is great and you will likely soon buy a standalone DAC.  Experiment until then. 

Jerry

short answer, you have both units, so you should try all the possible combos and listen, decide which you like best -- also, iirc the node 2i does not support usb 2.0 digital out to an outboard dac, only spdif out

my guess, having had a node 2i (but not your mac unit) is that the best sounding way will be rca coax digital out from node into the digital input of the mac

the onboard dac in the node 2i is unremarkable, to put it nicely... that was the major improvement they made when they released the node 130 (that and giving users a usb out to drive another dac)