MAC to DAC connectivity

Thanks. It is an interesting solution, and kind of elegant....but I think I would be duplicating DAC functionality between the Audioengine and my Orchid....so it becomes less attractive from a cost and stranded capability for me (i think).

Well, it is true that you would be paying for a dac that in effect you would not be using, i.e. the one in the Audioengine receiver, on the assumption that your Orchid turns out to be superior to the AE dac. 
On the other hand, you would be able to do quick AB comparisons between your Orchid and the AE dac, simply by switching from one input to the other on your integrated amp--- I am doing it right now with my Denafrips Ares and the AE dac.... Kind of interesting.
But, seriously, I am straying from a focus on your concern as registered in the OP, namely, getting a good solution to the problem of establishing an effective Mac to dac connection over a distance of approximately 20 feet. The best solutions would involve going "wireless" over the distance, which is why I even brought up the Augioengine D2 idea.
Good luck and happy listening, Sir. 

@stuartbmw3 .. looks good. Please let us know how you like the DAC and cable arrangement. Best.

I have both USB and Ethernet interfaces to my DAC, using S/PDIF coax. I can do WIFI as well using an Ethernet-WIFI adapter.

By far, the best SQ is achieved using Ethernet, but the devil is always in the details. If you use a converter for Ethernet to S/PDIF or USB to S/PDIF, the input and output cables must be great quality or the SQ will suffer. These distances are really a non-starter for USB IME.

I would suggest the following:

1) connect an AQVOX switch to your router using a long generic CAT5 or 6 Ethernet cable.
2) Use a high-quality 0.5m Ethernet cable like the Wireworld Platinum from AQVOX to an isolator,
3) Use a EMO EN-70e isolator:

https://www.emosystems.com/?s=en-70e

4) Run a second 1.5m high-quality Ethernet cable (Wireworld Platinum) from the isolator to a low-jitter Ethernet Renderer like the Interchange:

https://www.audiocircle.com/index.php?topic=156409.0

Then run a high-quality 1.5m BNC-BNC S/PDIF cable from the Interchange to your DAC.

This will deliver optimum SQ using the shortest cables and the best converters.

Steve N.
Empirical Audio

Does anyone know if there is a way to get optical output from the MAC to the D2's optical input? I have been using the usb input and the optical out from the D2 into my Krell. Sound is pretty decent but wondered if the optical from the MAC is possible.