Coax to BNC connection for digital

Sounds like a plan!  All the best to you and yours for the new year.

Best regards,
-- Al

Hi Mesch,

My reference to the fact that some equipment (mainly some pro equipment) provides a 75 ohm AES/EBU interface on a BNC connector was a lighthearted response to what appeared to be your not very serious reference to the possibility that your "mind may not be keeping up," for not having correctly recalled the kind of interface that is provided on the DAC. :-)

To connect a 75 ohm S/PDIF output to a 110 ohm balanced AES/EBU input you would need a device such as the following, as well as a 110 ohm balanced cable to connect the output of this device to the 110 ohm AES/EBU input:

https://www.bhphotovideo.com/c/product/395533-REG/Hosa_Technology_CDL_313_CDL_313_Data_Link.html

Using simple adapters to connect an unbalanced 75 ohm S/PDIF output to a balanced 110 ohm AES/EBU input **might** work in terms of functionality (i.e., it may play music), depending on the specific equipment, but it would be very unlikely to be sonically optimal.

Best regards,
-- Al

Actually some equipment provides an AES/EBU interface on a BNC connector, with a 75 ohm impedance!

From this Wikipedia writeup:

AES/EBU can also be run using unbalanced BNC connectors with a 75-ohm coaxial cable. The unbalanced version has a maximum transmission distance of 1000 meters as opposed to the 100 meters maximum for the balanced version. The AES-3id standard defines a 75-ohm BNC electrical variant of AES3. This uses the same cabling, patching and infrastructure as analogue or digital video, and is thus common in the broadcast industry.

Best regards,
-- Al

That should work well, Mesch, assuming the BNC input is 75 ohms (as is likely) and not 50 ohms.  Also, it would be preferable to use an adapter specified as 75 ohms, such as the one I linked to earlier.

Best regards,
-- Al

Given the DAC has BNC, should I purchase a server with BNC output I would  then just purchase a BNC cable which I suppose would need be rated for 50ohms.

Hi Mesch,

The output impedance of the server, the input impedance of the DAC, and the impedance of the cable should all be the same, or there may be adverse sonic consequences that are equipment and cable-dependent, and that are essentially unpredictable.  BNC outputs, inputs, and cables used in digital audio applications are often 75 ohms, but are 50 ohms in some cases.  It would definitely not be good practice to connect a 50 ohm output to a 75 ohm input, or vice versa, although in some circumstances doing so **might** happen to provide reasonably good results. 

Best regards,
-- Al

Hi Mesch,

To add to Auxinput’s response, just make sure that the input impedance of the BNC input and the impedances of the cable, the BNC connector(s) on the cable, and any adapters that are used are all 75 ohms, and not 50 ohms.

Also, if you already have a suitable 75 ohm RCA-to-RCA cable at hand, you might consider trying it in conjunction with an inexpensive 75 ohm BNC male to RCA female adapter, such as this one:

https://www.bhphotovideo.com/c/product/1024160-REG/remote_audio_app38_rca_phono_female_jack.html

Happy holidays! Best regards,
-- Al