Constructing BFD interconnects for sub...

Discussion in 'Archived Threads 2001-2004' started by Clay Autery, Aug 18, 2002.

  1. Clay Autery

    Clay Autery Stunt Coordinator

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    Well, I finally got around to pulling my BFD out of the box today... My questions revolve around building the right interconnects to insert it between my Denon AVR-4800 and the Sub amp...

    I'm assuming that I need two cables, both with RCAs on one end and XLRs (or 1/4" TRS) on the other....

    Can I still use the same Cnare cable I use otherwise for my standard unbalanced RCA sub cables? Do I just bridge the appropriate pins in the XLR plugs at the BFD?

    OR would it be better to use the type of cable utilized in balanced cables (what... shielded twin-ax... shielded single twisted pair?) and bridge the appropriate conductors at the RCA connector (solder RCAs)?

    It'd be cool to be able to build these cables and play around with (become familiar with) the BFD before I get my new sub built...

    Thanks,
     
  2. ThomasW

    ThomasW Cinematographer

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    I just bought RCA to 1/4" adapters then used standard interconnects
     
  3. Clay Autery

    Clay Autery Stunt Coordinator

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    That's an option, but I'm partial to making my own cables.... and don't much care for adapters...

    So it's either L-5CFB cable and bridge inside the XLR connector, or use some sort of shielded 2 conductor wire and bridge at the RCA connector... I'd LIKE to try both to see which works best, but I already have the Canare wire, tools, and RCA connectors, so I guess I will likely try the coax version first....

    Who makes XLR connectors on a quality par (or better) with Canare?
     
  4. Wayne A. Pflughaupt

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    Clay,

    The simplest route is to buy pre-made, off-the-shelf ¼” – RCA cables.

    If you intend to make your own there are a few options, but all of them will require soldering as there are no crimp-on ¼” or XLR connectors that I know of.

    For XLR cables, the center conductor (signal +) would connect to pin 2, and the shield (signal -) connects to pin 3. You can put a jumper in between pins 3 and 1, but it shouldn’t be necessary. Be sure and watch out for the opposite placement of pins 1 and 3 on the male vs. female connectors.

    For ¼” TRS plugs, the center conductor goes to tip and the shield goes to ring. Again, a jumper from ring to sleeve is optional.

    However, there’s really no reason to use TRS and XLR connectors. Standard mono ¼” plugs will work fine, and they are cheaper.

    Regards,
    Wayne A. Pflughaupt
     
  5. Clay Autery

    Clay Autery Stunt Coordinator

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    But buying pre-made cables would deprive me of the opportunity to make them.... [​IMG]
    Soldering is no problem at all... and the pinouts are in the BFD manual as well...
    Guess I'll go with the Canare cable/RCA and some XLRs... I like the locking feature of the XLR connectors...
    I would like to have some suggestions on a good shielded 2-conductor cable to use to make a comparison set of cables with solder on connectors at both ends...
    I deally, it'd be cool to find very-low capacitance, 2 conductor wire, individually shielded with foil/braid, and overall shielded with foil/braid. Then you could bring the centers off the BFD's XLR connector ike a balanced connector and combine the individual shields as the shield. Then, at the other end, you could combine the shiled and sig(-) at the RCA connector.... The overall braid could be used as a drain connected to the chassis ground on one end or the other... Wonder what it would do....
    [​IMG]
     
  6. Wayne A. Pflughaupt

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    Forgot to mention:
     
  7. Clay Autery

    Clay Autery Stunt Coordinator

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    Yup... knew Canare didn't make XLRs... weird since they make XLR patch panel components... [​IMG]
    I was seriously considering the Canare mic cable... guess I'll use that...
    And on the "theory"... Didn't figure it'd make any difference... Just brain-storming... [​IMG]
     
  8. Clay Autery

    Clay Autery Stunt Coordinator

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    Using Canare L-4E6S Star-Quad mic cable, Neutrik NC3FX and NC3MX XLR connectors, I made my first custom (balanced) XLR cable (for the run between the BFD and the Crown CE-1000 amp... still have to make the RCA to XLR cable for the receiver pre-out to BFD).
    Here's a pic:
    [​IMG]
    I have a question though... Both of the pin cores (male and female) have what looks like a possible fourth contact on them. I'm wondering if they are indeed some sort of contact or not. It LOOKS like (by the little "eyelet" in them) that this may be some sort of contact for use with a drain wire or something. If you connected a conductor to these "eyelets", you would effectively be connecting them to the connector housing and hence to the chassis connector housing... Here's a pic:
    [​IMG]
    What I am talking about is at the top of the pic.... What is that for? (other than apparently being part of the spring mechanism in the female connector) Is it a drain wire contact? When would you use it?
    Thanks,
     
  9. Clay Autery

    Clay Autery Stunt Coordinator

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    Can anyone help ID the 4th tab/contact with the "eyelette" that I referenced above?
    Please... [​IMG]
     

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