Balanced vs Unbalanced

Discussion in 'AV Receivers' started by StanB, Jul 27, 2005.

  1. StanB

    StanB Agent

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    I see a distinction between "Balanced XLR" interconnects and "Unbalanced RCA" interconnects. Would someone place explain the difference. Is one always better than the other?
     
  2. John Garcia

    John Garcia Executive Producer

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    XLR is a completely different connection type from RCA. The main difference being that the XLR has a separate connection for ground (balanced, all conductors are equal), vs many RCA cables that use the shield as ground (unbalanced). There are balanced RCA cables too, that use a separate conductor for ground. The difference is better noise rejection with a balanced cable.
     
  3. StanB

    StanB Agent

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    The reason I was asking was that my Rotel 1090 amp has rca unbalanced and xlr balanced inputs. I have a rotel 1068 processor and currently have rca unbalanced cables. I didn't know if switching is worth the expense.
     
  4. Kevin C Brown

    Kevin C Brown Producer

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    I've never seen that. ?? (Have seen shielded RCA cables though.)

    Plus, the reason why a balanced cable works, is that one line is ground, and one line is the signal, and one line is the signal but out of phase. At some point before the signal is outputted to the speakers, the out of phase signal is subtracted from the in phase signal. The two signals add together (that's why the common 6 dB boost for balanced connections/inputs), but the noise is subtracted out. a - (-a) = 2a.

    Balanced RCA cables don't make any sense, because neither the sending or receiving component puts that 3rd line out of phase.

    Do you mean, shoot, the TRS (?) cables for pro gear? A cable with kind of like a headphone jack at the end?

    Stan- How far away is your amp from the pre/pro? A lot of people feel that balanced cables don't get you much unless that distance is large. > 10 ft or something. Plus, Rotel gear is not *fully* balanced anyway, so it *is* possible that its balanced connections could add noise, due to the additional circuitry required.
     
  5. John Garcia

    John Garcia Executive Producer

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    Basically, the "balanced" RCAs keep the sheild and negative separate, so it is not quite a true balanced design, that's just what they call it:


    What they basically did is use an XLR cable with an RCA connector. I use these ICs in both of my systems and they work quite well.
     
  6. Chu Gai

    Chu Gai Lead Actor

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    Well, unless you've got your amp on one end of your room and the processor way over on the other, and as a result you're somehow picking up noise, the answer is no. In fact, even if somehow running extraordinarily long lengths of RCA did result in a pickup of noise or hum from extraneous sources, there are ways around it.
     
  7. John Garcia

    John Garcia Executive Producer

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    For RCA over long lengths, especially in wall, you can use RG6 coax terminated with RCAs.
     
  8. Wayne A. Pflughaupt

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    As they should. Theoretically, sending the negative down a separate conductor will help make the cable better resistant to interference, so long as the two center conductors are internally twisted (most are). It’s the turning-over of the signal that accomplishes the resistance to interference (note that some overpriced “tweaky” interconnects use only the twisted conductors, sans shield).

    Nonsensical hype aside, it’s a sound way to build audio interconnects, even if you’d be hard-put to tell any difference between them and more conventional cables. My custom cables (Canare and Mogami stock) are made the same way. [​IMG]

    Regards,
    Wayne A. Pflughaupt
     
  9. Kevin C Brown

    Kevin C Brown Producer

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    Bingo! I had sort of forgotten, but this is the kind of interconnects I use. Free plug: www.bluejeanscable.com [​IMG]
     

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