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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
jasonbourne52's avatar
jasonbourne52
2,863 posts
 

Minimum length for a coax digital cable is 1.5 meters. Less than that and problems can arise from reflections within the cable.

kijanki's avatar
kijanki
4,432 posts
 

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

corelli OP
1,015 posts
 

Thanks for the responses.  Confirms what I thought, but I was not aware of the minimum length suggestion.  Good info. 

williewonka
3,082 posts
 

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

auxinput
2,920 posts
 

@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.

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