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HDTV has no "Analog Audio Output"

Discussion in 'Electronic Design' started by Biggy, Feb 5, 2006.

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  1. Biggy

    Biggy Guest

    Hi Guys

    My friend has a 42" LG Plasma HDTV (DU 42PX12X) it has only one audio put
    via digital "optical" output. I am trying to help him connect it to his
    amplified speaker system. The HDTV has one extra monitor RCA audio output
    but only works when you are watching standard TV and processor disconnects
    it on HDTV channels.

    Checked with LG Electronics who advised as follows:

    (1) When receiving digital TV signal then no analogue audio signal available
    from Monitor-Out, RCA connections
    (2) When receiving analogue TV signal then yes analogue audio signal
    available from Monitor-Out, but need to turn off internal speakers
    (3) Digital audio output available at Digital Audio Output (Optical)

    I would have thought that it would be fairly simple matter to capture the
    analogue audio signal at the internal speakers, irrespective of whether the
    TV signal is digital or analogue.

    I was thinking of trying to open the set and tapping off the speakers left
    and right with a simple voltage divider. I could ever make it a variable
    attenuator. Only problem is I don't have a schematic I want to make sure the
    audio output is not floating as I will have to ground one leg of the
    divider. I guess I could measure the resistance to ground on both sides of
    the speaker out to see if one side is grounded? Sure wish I new the correct
    procedure to access the speakers there is lots of screws all round the TV.
    This is first time I have had to work on a plasma TV.


    He all ready has an nice amplifier and speakers and doesn't really care for
    Dolby Digital or surround sound and stereo would be fine.

    He wants to operate his system via the TV (one) remote. If he purchases a
    home entertain system he will have one for TV and one for volume and one for
    DVD player.

    I also know that you could purchase a universal remote, but it can be very
    costly ($300) and is headache to program.

    Any comments

  2. Wrong newsgroup. The TV techs are at
    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
  3. Jim Thompson

    Jim Thompson Guest


    My oldest son has a similar problem with a Sony set. We're trying to
    figure out the least complex way to get the "optical" audio into a TV
    modulator for distribution throughout the house.

    ...Jim Thompson
  4. correct

    If it's not grounded on one side, just use one of the speaker terminals
    and put your voltagedivider between that and ground.
    Yes, lots of screws. Place it face down on a table, and start screwing ;)
    Beware if screws have different length, don't mix them up. First unscrew
    those that are in deep holes, the others may have nuts on the inside, not
    meant to be loosened. Try to stay friends with your friend.
  5. Pooh Bear

    Pooh Bear Guest

    He bought the wrong TV.

  6. Jim Thompson

    Jim Thompson Guest

    Nope. All NEW sets seem to be that way.

    Appears to be a part of the DMCA crap.

    They don't want you to be able to input one format and output another.

    Heavens! You might COPY something ;-)

    ...Jim Thompson
  7. Pooh Bear

    Pooh Bear Guest

    I have a way of dealing with that.

    I don't buy crippled crap.

    This 'copy protection' has indeed got out of hand though. The programme
    makers ( and makers of other media ) are treating their customers as

  8. Pooh Bear

    Pooh Bear Guest

    I wonder if there's a market for a stand-alone decoder box for optical ?

    I certainly don't want the bother of multi-channel surround. Most UK (
    read European and rest of the world except USA ) homes are too small to
    have any sensible multi-channel setup anyway . Stereo is just fine by me.
    In fact most of the time I listen using my TV's internal speakers. Hooking
    it up to the hi-fi is imply too intrusive for everday stuff ( but
    admittedly nice for effect if you're really seriously watching a feature
    film ).

  9. Jim Thompson

    Jim Thompson Guest

    Unfortunately it's not just media or "programme".

    My son's equipment will only "line-out" in the same format as

    Maybe there's a business there ?:)

    ...Jim Thompson
  10. Jim Thompson

    Jim Thompson Guest

    There's nothing quite like surround sound for a movie like "Red
    October" ;-)

    ...Jim Thompson
  11. Well, that would be "stealing" their IP, wouldn't it? :)
  12. Apparently, but you can't find a HDTV->NTSC converter because the standards are still in Lala land. Theres a problem with
    broadcasters being able to choose wether or not you can view the signal with some encryption. Thus potentially breaking any
    converter made today.

    I hope they iron this out by the due date ;D

  13. Robert

    Robert Guest


    Until they make it illegal like the A/D bill Win was talking about?

  14. Yup and they exist.

  15. It's probably *already* illegal in the USA; circumvention of an
    anti-piracy device.
  16. Joseph2k

    Joseph2k Guest

    What is so hard about puting it through the SPDIF chip from any current home
    entertainment "receiver" and using the output of that?
    Oh hell, is everything but the RF and PA on one chip?
  17. Pooh Bear

    Pooh Bear Guest

    The presumption being that you have to have a 'home entertainment receiver' in
    the first place !

  18. My Samsung SIR-T165 set top box for the DLP monitor has a switch on the
    back to select the output format. One of the selections is 480i which I
    used with a Mitsubishi NTSC set for a few days until I got the DLP in
    December of '03. It doesn't have an RF modulator but that is all it
    would need -- though it was WAY too expensive for the masses. Point is
    it can be done.
  19. Easiest way is to put a small coil of wire in front of the internal
    speaker, hook it to a "mic" input. Move the coil around til you get
    the best sound and minimum buzz, and you're all set.

    For the coil, get an old wall-wart, knock the laminations out of the
    transformer, and use the line prongs as the signal source. Voila,
    instant sound capture device. Also works to capture audio from
  20. Pooh Bear

    Pooh Bear Guest


    I'm sure the wife reckons that's a great improvement on the aesthetics
    of a multi-thousand dollar set. Even if it works decently which I
    suspect is doubtful.

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