Does anone here use mini BNC's...

Discussion in 'Home Theater Projects' started by Neil Joseph, Sep 1, 2003.

  1. Neil Joseph

    Neil Joseph Lead Actor

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    to use as a component connection to their display device or projector? I was contemplating replacing my 3xRG6 cables but I borrowed a high end BNC cable and A-B'd it this weekend. It basically has 5 cables in it (R,G,B,H,V) which are all terminated with the BNC connectors. I saw no difference at all between it ($300) and my RG6.

    This was for DVD viewing.
     
  2. Chu Gai

    Chu Gai Lead Actor

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    I take it you meant BNC Neil? I don't suspect you'd see any difference. The length of the actual connector is too small to have any signficant contribution to the impedance as compared to the wavelength of the signal being transmitted. There are 2, maybe 3 flavors, of those I've seen being made. A 50 ohm, 75 ohm, and what appears to be a more tightly controlled 75 ohm cable.
     
  3. Neil Joseph

    Neil Joseph Lead Actor

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    Yes, BNC. I could see no difference but I often wonder if I would had I been using a HDef source.
     
  4. Chu Gai

    Chu Gai Lead Actor

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    Well one way to play this Neil is to contact the manufacturer for their input. I will say though that the BNC is a much nicer connector than the RCA although there are several other 75 ohm connectors of greater repute than the BNC.
     
  5. Bob McElfresh

    Bob McElfresh Producer

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    BNC is considered a superior connector to RCA's. Nearly all professional broadcast equipment use them, as well as most scientific instruments that connect to coaxial cables.

    The 2 main advantages are:

    - Maintaining the center-to-shield distance to provide a consistant impedence for the signal.

    - The bayonet type connection wont pull loose like the friction-fit RCA plugs. This is VERY important for a broadcast studio where all kinds of tugs/weight/stress is applied to the cables while techs work on things.

    As Chu pointed out, there are some very good RCA plugs that give similar performance to BNC connectors (like the Canare RCA plugs), but they are expensive. (e.g. a BNC connector sells for about $0.49, a Canare RCA plug is about $2.25).

    In general: it's more important that the coax is rated for the frequencies you are using, then comes the BNC vs RCA issue. If you get a good RCA plug, it's not much different than a BNC in terms of signal-handling.

    But there are many RCA plugs that are 50 ohm (for audio) or some random number between 40-100 ohms that are NOT designed for 75 ohm impedence. In this case, cutting off the end and crimping on a BNC can improve things.

    If you already have a well-made cable, switching to some other cable with BNC connectors wont make much difference.
     

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