Why aren’t BNC jacks common?


Digital connection between a source component and DAC calls for typically other a 75 ohm impedance or 110 ohm impedance cable. Sourcing a 110 ohm cable is easy- it’s very common. But a 75 ohm cable? Not so much primarily because just about every RCA terminated cable is not a 75 ohm cable, however, true 75 ohm cable is a snap with BNC terminations. BNC is not expensive and arguably it’s a more secure connection than is RCA. I therefore do not understand why components with BNC jacks are very rare. Perhaps you can argue the ommission of a BNC connection is justified on mass market gear but on high end gear?  Can someone provide an explanation that makes at least some sense? My DAC supports BNC (Bricasti) but my CD transport (Simaudio) does not. Thanks!! 

zavato

BNC should be the standard.  Given the buckets of BS dumped on us by cable manufacturers about the importance of various materials and other features, this one seems like it should be a 2-foot putt.

BNC is widely used in industry for electronics cables for its secure connection. It is a better connector than RCA. 

The lack of familiarity in audio systems has hampered more wide acceptance.

There are adaptors for both BNC ->  RCA and RCA -> BNC. They are cheap and effective. I use them every time I want to look at line level audio signals on an oscilloscope or use any HP test gear.

@mitch2 it is a 2 foot punt, making it all the more inexplicable. I do t know how a high end company can in good faith offer a 75 ohm point of connection and not use BNC. 

I have owned multiple high'ish end DACs and very few of them had BNC connectors.  The adaptors may "work" to conduct a signal but in the audio world where I constantly read about how "everything matters" it perplexes me how something like this that is so simple to get right doesn't adhere to some sort of standard. FWIW, AI says,

BNC/RCA adaptors on a 75-ohm digital cable technically introduce an impedance mismatch, as BNC/RCA connectors are not designed for true 75-ohm impedance. While the cable itself remains 75-ohm, RCA connectors are generally around 50 ohms or non-impedance-controlled.  Therefore, the connector transition can create small signal reflections. However, at typical S/PDIF frequencies and short cable lengths, this mismatch is often negligible.

I have gone back to using USB connectors into both of the DACs in my main system, because IMO they sound better.

 

This has baffled me as well, BNC is such a superior connection. I don’t use SPDIF in my system anymore, but I always had either BNC or AES as a requirement when I did.