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PROBLEM: CD Player Digital Output

Discussion in 'Electronic Repair' started by EADGBE, Jul 10, 2008.

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    EADGBE Guest

    I have a Yamaha CX-1000 preamp and I just acquired a used Yamaha CD
    player that has a digital output (CDX-710).

    The CX-1000 preamp has digital inputs on it. Even though this CD
    player sounds fine through the analog outputs, I wanted to hear what
    the digital output sounded like.

    I used a Monster Cable Datalink SP/DIF cable I had lying around to
    connect the two.

    PROBLEM: I get perfect audio through the left channel, but nothing at
    all in the right channel. Needless to say, the CD player sounds great
    in BOTH left & right channels when I use its analog outputs.

    What could the problem be? I am unfamiliar with making digital
    connections. Could I be using the wrong kind of cable? If there is a
    breakdown somewhere, what would be the most likely problem?

    I was always under the impression that digital, by definition, either
    works or it doesn't. But I have a situation where "half" of it works
    and the other "half" doesn't.

    The problem doesn't really bother me, since I am satisfied with using
    analog connections. But I am a bit puzzled about why I can't get both
    channels working when I try to use a digital connection.

    Thanks in advance for any assistance......
  2. Adrian C

    Adrian C Guest

    Fault in the preamp, I'd wager. Do you have anything else with a digital
    output you could try?
  3. Arfa Daily

    Arfa Daily Guest

    Agreed that you need to try something else as an input. Problem could be at
    either end in that both channels may not be making it into one data stream
    at the CD (unlikely) or (more likely) that the Yammy is either failing to
    decode the missing channel, or failing to switch it. Do you have only a
    coaxial digital connection ? Is there an optical one that you could try ?
    Either coaxial or optical, you are correct in your assumption that it should
    all "just work" as soon as you make that one connection.


    EADGBE Guest

    This particular CD only has the coaxial output -- there is no optical
    output, although there are optical inputs on the preamp.

    I have an Audio Alchemy CD player that also has a coaxial output, but
    that player is not working at the moment.

    One other though occurred to me: I should try the CD player into some
    of the other digital inputs, just to see if maybe the CD input alone
    is at fault (not likely, I know).
  5. So which is it holmes? The Sending Device of the Receiving Device?
  6. Mike S

    Mike S Guest

    That narrows down the possibilities! At least he knows it's not the cable

  7. Could someone please explain how it could be possible to lose one channel of
    the digital stream out of the CD player, considering that the CD's audio
    output is perfectly OK.


  8. I would say close to Zero. I'll bet nobody here can cite a case where this
    has actually happened.

  9. Arfa Daily

    Arfa Daily Guest

    It is very unlikely, I agree, but then in these days of extremely complex
    internal architecture of most LSIs, there isn't much in the way of 'stock
    faults' any more, and strange ones happen every few weeks in my experience.
    That being the case, none of us could cite a case of a peculiar fault, until
    it actually happened :)

    Unlikely or not, there is the remote possibility that this could be the one
    for that fault ... I don't know if the PCM data stream coming off the disc
    is decoded and processed first, or whether it is directly transcoded into
    SPdif (or indeed, whether SPdif is just PCM under another name - I've never
    bothered to check because it's very rare to get *any* fault in this area).
    If there is any decoding going on, then just maybe, a channel *could* be
    lost. But yes, in practical terms, almost certainly a problem in the amp.

  10. Eeyore

    Eeyore Guest

    Obviously you should have used a Monster STEREO cable instead of the cheap
    model you bought.

  11. Eeyore

    Eeyore Guest

    Don't tell the audiophools that ! Their entire religion will be destroyed.

  12. Eeyore

    Eeyore Guest

    Failure to sync to the second block of audio data ? Bad clocks ?

  13. Eeyore

    Eeyore Guest

    Try using a cheap one.

  14. Eeyore

    Eeyore Guest

    You mean I2S.

    It is. Both are linear PCM. Simply mildly different data stream formatting.

  15. Mike S

    Mike S Guest

    Yes. In the digital output the left and right channels are combined into
    one digital stream, then sent over the coax cable to the receiver/preamp
    where they arer separated into the two analog channels.
    The problem here is in one of those stages. Either one of the channels is
    being lost before it is encoded into that digital stream to be sent out of
    the CD player, or a perfect digital stream is being sent to the preamp and
    sometime after it is decoded into the two seperate channels, one channel is
    lost due to a faulty component or a bad solder joint, loose connection, etc.
  16. EADGBE

    EADGBE Guest

    I have received a couple of comments here that my cable choice could
    be the problem.

    Is it actually possible that a cheaper cable could solve the problem?

    And here is a question that will really show my level of ignorance
    when it comes to digital audio formats: Is it possible that I am using
    the wrong kind of digital cable? The digital output of the CD player
    and the digital input on the preamp are both RCA type jacks. I simply
    thought that using a digital coaxial cable with RCA plugs on both ends
    would be appropriate. Am I wrong? Is there another type of cable I
    should use that will fit?
  17. Adrian C

    Adrian C Guest

    Nope. Absolutely not.

    Have you got some other digital audio source to check this problem yet.
    DVD player?
  18. Arfa Daily

    Arfa Daily Guest

    Why ! - that's what makes life interesting, of course ... :)

  19. The sending device might be coding the datastream as a mono feed, or the
    receiving device is failing to decode the datastream as a stereo feed. It
    might be something as simple as a configuration problem (one of the devices
    is set to 'mono'). To diagnose a fault, use a protocol analyzer, or a
    process of elimination by substituting components until you get something
    that works.
  20. Phew, after all that speculation we finally got some technical insight.

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