Digital coax from CD player to DAC, RCA or BNC-RCA?

I did a bunch of testing and made several attempts to test different RCA plugs in a digital cable.  In all instances, the sound was always the best using BNC connectors on the end of the cable and then attaching a BNC-to-RCA adapter.  I tried DH Labs RCA-750, WBT Nexgen and even  Furutech CF-102 (Furutech was the worst).  Using just RCA connectors on the cable resulted in high frequency loss in the audio when compared to BNC cables with BNC-to-RCA adapters.

The highest resolution BNC-to-RCA adapter is the Black Cat adapter, but the RCA plug doesn't have a lot of grip so heavy cables will tend to cause the RCA plug to lean down.  Otherwise, get the cheap gold-plated BNC-to-RCA adapters from monoprice and different distributors.

The Canare BNC-to-RCA adapters are not good and cause the sound to be messy in the high frequencies.

Thanks for all the input.

@dabel I did purchase a Nordost Silver Shadow BNC digital coax with the RCA adapters from a member here, NIB. Thank you for pointing me in that direction.

I will gladly report my findings once everything is up and running.

I also don’t care for adapters

As a general rule I don’t either — less is more.  But I too was told by someone who designs expensive DACs that it’s preferable to run a balanced digital cable with RCA adapters than one that’s RCA terminated.  I don’t know why and have nothing to back this up, and I’d also think it depends on the quality of the adapters as well so they don’t do more harm than good.  Interested in what others think on this. 

@buff sometimes has the No’s Silver Shadow an excellent cable.
I also don’t care for adapters, the input lock / relay on my Aesthetix DAC often rejects connection made w adapter.
careful shopping might yield an Audioquest Eagle eye cable w factory bnc - my reference cable…

This is an excellent digital cable — it has the desirable traits of being detailed and neutral yet also very natural sounding.  My advice would be to start with this $55 cable and enjoy until you find something better, but I ended up just keeping this and spending the extra $$$ elsewhere.  Best of luck. 

https://smile.amazon.com/dp/B01N4UMC4N/ref=twister_B01MUH69P1?_encoding=UTF8&psc=1

For me BNC connectors are the best. I'm not a big fan of adapters, but if you cannot replace the RCA's with BNC's on both the cable and equipment, then Sliver Shadow would probably be a good option. I have found that the connectors are usually the weakest link.