RV surround sound = HDTV into Sony CD player?

By L6Griffin
Feb 7, 2011
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  1. I would like to run the audio from HDTV (Vizio M261P) into my Sony (CDX-GT520) CD player. The Sony has an AUX input to connect portable audio devices, no other info given, and per-amp (BUS?) inputs. I tried plugging the audio out, and the computer audio out into the Vizio into the Sony AUX all I got was a loud hum. I'm not sure what the pre-amp inputs will handle.

    I've posted several times before and gotten great answers.

  2. jobeard

    jobeard TS Ambassador Posts: 9,156   +598

    this means you have bad cables and/or one device or the other is not grounded with the A/C power cord.
  3. L6Griffin

    L6Griffin TS Member Topic Starter Posts: 16

    I'll check the cables, but grounding could very well be the problem. The Sony is on the motor battery, and the Vizio is on the coach battery, running off a DC to AC converter. I may have to get a DC(12v) to DC(19.5v) converter, and a 12v to 5v.

    I haven't finished the wiring yet. Eventually there will be the Sony, Vizio, laptop, and USB hub, off the coach batteries.

  4. jobeard

    jobeard TS Ambassador Posts: 9,156   +598

    oh boy - - got a real project there.

    I've done shortwave mobile radio in another life - - here's some tips.

    Create a ground to the frame of the vehicle for all audio/video devices.
    You may also get noise from the alternator and/or converter. Take the power outputs and
    place a 0.001 ufd capacitor (25v for the alternator; 200v for the converter) to the nearest ground - - test the ground with a VOM, ohm meter
    from where you intend to make the attachment to an obvious frame component. The reading should be ZERO ohms - - that says your mounting point is good and not floating.

    Place the capacitor inside some shrink-wrap tubing, add a forked spade pattle to one end to fit the power line as close to the source as possible and the other end goes to your selected frame point. Once connected, take a heat source and shrink the outer casing in which you have the capacitor.
  5. L6Griffin

    L6Griffin TS Member Topic Starter Posts: 16

    The project is actually on hold. The weather has been great so I was prompted to reseal the roof. I bought the RV about 2 months ago.

    I found some DC to DC converters that look like they will do the job on ekbay from China.

    Adding the capacitors seems to be simple enough, except, the alternator and converter are not near to each other. If I add the caps at the alt source to the chassis, and the converter source to the coach frame. Then make sure (VOM) that the chassis and frame share a common ground, even if ground straps are necessary. I should be able to to ground the audio/video to the same point either chassis or frame.

    Thanks again,
  6. jobeard

    jobeard TS Ambassador Posts: 9,156   +598

    btw: the caps need to be 0.1 ufd, NOT 0.001 :( The lower value is for high frequencies, and you need a low frequency filter - - sorry for the confusion.

    yes, I expected the converter and alternator to be well separated - - the 'common' ground is
    the electrical effect of attaching to any frame member :)

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