DIY SPDIF Coax

[Barry]

Many BNC connectors use the same dielectric regardless of impedance. Thus the 75R connectors use a smaller diameter inner conductor compared with the 50R versions. So if one tried to mate a 50R BNC plug with a 75R BNC socket, the socket would be damaged.

That is why the BBC insisted on using only 50R BNCs, regardless of application. https://theartofsound.net/forum/show...dio-Connectors

However some 75R BNC designs dispense with the dielectric in the region where the connectors mate, and can thus use the same diameter for the inner conductor as that of the 50R connectors (the dielectric will have a relative permittivity of ~ 2.25, so the impedance ratio is reduced by 1.5). With these designs the two impedance versions can be physically mated without damage.



But all RCA connectors are IMO lousy and would be better replaced with BNC, which are of a similar size and are a much more precise and rugged connector.

[Edward]

This thread got me looking at the cable between my Digi+ S/PDIF out which is connected to the DAC. The cable is a Belden 1694A with RCA Canare plugs.

The cable is marked 'Video Brilliance (R)'.

Is this cable rubbish and I need to go elsewhere?

[Barry]

It looks fine to me Edward.

The Belden 1694A cable is the same as RG-6/U: https://catalog.belden.com/techdatam/1694A.pdf, and the plugs are the same as those on the lead mentioned by Grant: https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1, the latter of which are crimped onto the cable and is IMO the better way of attachment.

The Belden cable has slightly less loss compared with the Mogami cable.

[Edward]

It looks fine to me Edward.

The Belden 1694A cable is the same as RG-6/U: https://catalog.belden.com/techdatam/1694A.pdf, and the plugs are the same as those on the lead mentioned by Grant: https://www.amazon.co.uk/gp/product/...?ie=UTF8&psc=1, the latter of which are crimped onto the cable and is IMO the better way of attachment.

The Belden cable has slightly less loss compared with the Mogami cable.

Ah thanks Barry for going through all of that for me. Appreciated. So I will not look further knowing all is fine. You saved me some time and money. Cheers.