Is it possible to use RCA cables for a digital coax connection?

Discussion in 'Archived Threads 2001-2004' started by Gary_Roberts, Dec 28, 2001.

  1. Gary_Roberts

    Gary_Roberts Auditioning

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    I just bought a dvd player, and there's I need a coax cable, but there's no stores open now. Is it possible for me to use an RCA cable, (or some other suggestion) to test this out?
     
  2. Marc Rochkind

    Marc Rochkind Second Unit

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    Sure, for testing it out.
     
  3. Gary_Roberts

    Gary_Roberts Auditioning

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    what's the difference between RCA and store bought digital coax?
     
  4. Marc Rochkind

    Marc Rochkind Second Unit

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    Well, "RCA" just refers to the type of connector on the end, which is also called a "phono plug."

    A digital coaxial cable is just one of the many kinds of cables that could have phono plugs on the end.

    If you're asking whether the type of cable matters.. that is, whether a cable intended for analog audio would do as well, I would the proper cable would work better.
     
  5. Gary_Roberts

    Gary_Roberts Auditioning

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    Thanks (you're fast)
     
  6. ArmenK

    ArmenK Stunt Coordinator

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    I believe an RCA/composite cable is exactly the same thing as a digital coax cable so I dont think you need to buy a new cable if you already have a decent RCA cable around.
     
  7. BruceD

    BruceD Screenwriter

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    The difference between a standard audio interconnect (IC) with RCA connectors on each end and a digital IC with RCA connectors on each end is the following:

    1) standard analog audio IC with RCARCA is a 50 Ohm cable

    2) digital IC with RCARCA is a 75 Ohm cable

    and so is a component video IC with RCARCA

    In fact if you buy an RCARCA cable labeled "AV cable 75 Ohms" you can use it for everything (audio IC, digital IC, component video IC).

    The critical issue here is that digital and video require a 75 Ohm cable, audio doesn't care between 50 Ohm or 75 Ohm.

    That's all there is to it.

    BruceD
     
  8. Richard Burzynski

    Richard Burzynski Second Unit

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    Gary:

    Definitely test it out.

    Rich B.
     
  9. dougW

    dougW Stunt Coordinator

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    Bruce, nice answer. I will add however, that 75 ohm cables are not optimized for audio only applications which are around 50 ohms, though they will carry audio. I personally don't feel a coax has enough physical volumn to be ideal for analog audio. For example, a 22-26 AWG coax strand, isn't near the physical makeup of a 16 AWG stranded audio wire.

    Lex
     
  10. Jagan Seshadri

    Jagan Seshadri Supporting Actor

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    Those impedance values only start making sense with signals in the MHz range and higher, such as video signals. Audio frequency electrical wavelengths are so long compared to interconnect lengths that impedance mismatch reflections are negligible.

    So, use 75-ohm coaxial cable for video, but don't worry about that for audio, although 75-ohm interconnects for audio won't hurt.

    -JNS
     
  11. Mark Rich

    Mark Rich Second Unit

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    Doug ,

    Am I to understand that your argument is that bigger is better??? Let me guess you make 16awg cables ? Power cord maybe but not audio cables.That flies in the face of what most cable manufacturers and the audiophile crowd believes. Would love to read what the knowledgeable people over at cable asylum would have to say about that statement.
     
  12. Brian_C

    Brian_C Stunt Coordinator

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    Not trying to get into a big argument here, but Interconnect cables do NOT require large wire gauge, unless you are running them very long distances. The current of an Interconnect cable doesn't benefit from the much larger wire size.

    Either way, RG6 uses 18 gauge center conductor anyway.
     
  13. BruceD

    BruceD Screenwriter

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    Doug,

    Can't argue the 75 Ohm RG-6 coax issue, as I haven't tested any.

    But, just because a cable - like the RS AV gold series - has an RCA on each end and is 75 Ohm doesn't mean it necessarily uses the same gauge conductor as an RG-6 cable.

    Hope your cable business is doing well.

    BruceD
     

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