DIY Digital cable question


Need to make a short digital cable using Supra Trico coax cable.  There is a double braid on this cable.  The inner braid is the signal return.  The outer copper braid is for additional shielding.  When I asked the Supra rep how to connect the outer shield, he said to just let it float.  Everything I have read said it needs to be connected to ground on one end or the other. (Wish Almarg was still with us)

Thanks for the input.

corelli

RE:

I would connect outer shield to ground at the source (transport) side only

That is correct provided that the transport has a grounded three pin plug

If the transport has an isolated power supply then the grounded end of the cables should be plugged into the amp/Pre

  • assuming they have a three pin plug also
  • otherwise it makes no difference.

Regards

@williewonka - he's talking about a single-ended S/PDIF coax cable, so it will not have a 3-pin XLR plug.  However, this is not the same as a XLR analog interconnect.

@auxinput - RE:

@williewonka - he’s talking about a single-ended S/PDIF coax cable

The original posts stated...

There is a double braid on this cable. The inner braid is the signal return. The outer copper braid is for additional shielding.

In which case the outer braid can be used as a "floating screem/shield" - i.e. it should be connected at only one end

IF both components are "grounded" then that end of the cable should be connected to the source.

IF only one component is grounded then that end should be connected to the "grounded" component

IF neither components are grounded then connect that cable in either direction

BTW,

  • floating shields can be applied to both single ended and balanced cables - its how the wire is made and not related to the type of connection. 
  • and it provides benefit to both digital and analogue cables

@corelli - you can leave it "floating" at both ends and it will provide "some" benefit, but grounding at one end is better

Regards - Steve