Is there a commercially available audio cable with a built-in blocking cap?

Discussion in 'Professional Video Production' started by Ty Ford, Aug 18, 2005.

  1. Ty Ford

    Ty Ford Guest


    I've seen a lot of folks makeup cables to feed mono sources (mics) into mini
    TRS stereo inputs on camcorders. Hosa makes one, but it doesn't include the
    blocking cap that blocks the bias voltage some cameras put out.

    Anyone seen a premade cable with a XLR-F pin 2 that feeds both tip and ring
    of a 1/8" TRS that also has a blocking cap?


    Ty Ford

    -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
    stuff are at
    Ty Ford, Aug 18, 2005
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  2. Oleg Kaizerman, Aug 18, 2005
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  3. Ty Ford

    marcoleavitt Guest

    marcoleavitt, Aug 18, 2005
  4. Markertek appears to sell one: Part# XLF-H8-10 $49.95
    "TecNec Pro XLR Mic To 3.5mm Mini Cables for DV Cameras"

    "TecNec's exclusive mic cable design with on-board electronics
    allows prosumer camcorders to interface with professional
    microphones. Blocking capacitors built into the cable eliminate
    the 6-volt DC found on camcorder mic input jacks, eliminating
    hum. Built with Neutrik XLR connectors and TecNec Mic-BC
    shielded audio cable. 10 foot length."

    They appear to be charging ~$40 extra to install a DC-blocking
    capacitor in an otherwise conventional cable. But it must be
    a REALLY GOOD capacitor! :)

    OTOH, my web page appears to be pretty popular for DIY...
    Richard Crowley, Aug 18, 2005
  5. marcoleavitt wrote ...
    That is just an A-95 transformer connected to a short
    cable via the old-fashioned "coaxial-mic" connector.

    You can buy a XLR to 3.5mm mini-phone cable in lots of
    places. But most of them won't have the DC isolation from
    the transformer (or from a series capacitor in the XLR barrel).

    I'm not sure that particular transformer is really appropriate
    for a Lo-Z to consumer camcorder application, anyway.
    The unbalanced (output) side of that transformer is Hi-Z
    (like 40-50Kohms) which is a poor match with the Lo-Z
    input impedance of the average camcorder (likely 5K or
    Richard Crowley, Aug 18, 2005
  6. Martin Harrington, Aug 19, 2005
  7. Ty Ford

    Ty Ford Guest

    That's also been my experience.

    Ty Ford

    -- Ty Ford's equipment reviews, audio samples, rates and other audiocentric
    stuff are at
    Ty Ford, Aug 19, 2005
  8. Ty Ford

    marcoleavitt Guest

    I only point it out because it does indeed block DC voltage.
    marcoleavitt, Aug 19, 2005
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