Coax to BNC connection for digital

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

Thanks again Al for your help! That said, I am embarrassed in that I was mistaken about the additional input being BNC when in fact it is AES. My only excuse for my confusion is that I haven't received the DAC yet, a poor platform indeed. 

So I now must explore the subject of going from a coax RCA
 output to an AES input. 

I still can't believe that in my mind I replaced the AES outlet available on the DAC with a BNC one. AT 70 I feel I am in good physical shape, however my mind may not be keeping up.  

After some exploration I believe I am best off looking for a streamer/server with AES output and use appropriate 110 ohm XLR cable. This will be a 'down the road' investment. 

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

Well thanks again Al!  I really appreciate the time you have offered me on this.  I dare chance some more. 

The DAC am purchasing has the AES/EBU input that I likely will want to use. Currently I have both a DVD player and a CD transport with optical and coax SPDIF outputs. I also have two 1.5 meter 75ohm RCA cables available for use. I would prefer to use these cables between both the DVD player and the CD transport and the new DAC to avoid use of the optical connection.  Obviously this is no problem for one of the two disc players however the other will have to be connected to the AES input on the DAC. 

It is the impedance issue that has me confused. I know that a XLR microphone cable lacks the proper impedance for digital use. AES when balanced is 110ohms as I understand it. I believe with my new DAC I would be using a cable in unbalanced mode at 75ohms. I guess I need to verify this with Audio Mirror. 

If one has an 75ohm RCA cable can one fit a male RCA to male XLR adapter for my needs?  How does the impedance of the adaptor affect this? Or, based on the first sentence of the wikipedia report, can one use a BNC/AES adapter at the DAC input if one has a 75 ohm RCA to BNC cable?