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Grant Fidelity TubeDAC-11 Problem

Discussion in 'DACs' started by philviral, Nov 25, 2018.

  1. philviral

    philviral Active Member

    Messages:
    394
    Location:
    London, Ontario
    I need help diagnosing a problem that recently started happening with my Grant Fidelity TubeDAC-11. Whenever I use a digital input source, I experience a grainy/swirly distortion. I have tried using three different computers running Foobar2000. On all three machines I installed the Yulong ASIO drivers. I have tried listening to music with the Yulong ASIO driver selected as the output device, and with the primary sound driver. I get the same results with both devices. Adjusting the ASIO buffer size makes no difference.

    I also tried the Optical out from two of my computers, and experienced the same result. If I use the line input to the DAC, I get perfectly normal sound.

    I have recorded a sample of the song I've been using as a test to help illustrate the problem. The recordings aren't great but I think they illustrate the problem. Hopefully someone out there has run into something similar and can point me in the right direction!

    Problem sample:
    https://drive.google.com/open?id=18ZTVIVQ1zMd1ksOJ7N7UTfLnuWYQViLL

    Good sample:
    https://drive.google.com/open?id=1d8gnRrPMU2t_3d6eq0cgZhh59ysoBjBA
     

     

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  2. k1creeker

    k1creeker Member

    Messages:
    79
    I have the Tube dac-11, but haven't experienced the issue you mention.
    The line level in/out not producing the issue makes sense since you're not asking the DAC to do anything except pass the signal.

    Have you tried swapping the tube out for one you know works? ( assuming you're using the tube out).
    Swapped USB or Optical cables?
    Do you have a CD player you can connect to rule out an issue with the DAC or narrow the issue down to the computer?
     
  3. mroboto

    mroboto Super Member

    Messages:
    1,464
    Without an oscilloscope and knowledge to use it, it could be difficult to find the culprit.

    This could be a noisy AMS1117 regulator, or a bad cap that cannot properly filter the regulator noise, could be something else :dunno:
     
  4. philviral

    philviral Active Member

    Messages:
    394
    Location:
    London, Ontario
    Excellent suggestion to try another source. I've connected my home theater to the device using an optical cable and am experiencing the same issue. So I guess that rules out some kind of a driver issue and narrows it down to a problem with the DAC.

    I have not done anything with the tube because it sounds fine when I use the tube out with line in.
     
  5. philviral

    philviral Active Member

    Messages:
    394
    Location:
    London, Ontario
    I do have an oscilloscope and some basic knowledge of elactronics, I've dabbled in building a few things. Could you please elaborate on what I should look at?
     
  6. mroboto

    mroboto Super Member

    Messages:
    1,464
    Look if you have noise on DC components near the receiver and DAC chips.

    But a tube going bad could cause this kind of noise in a circuit, maybe the simplest thing to do is to swap the tube.
     
    Last edited: Dec 2, 2018

     

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  7. Wolfbane

    Wolfbane What's going on?

    Messages:
    318

    I own one of these DAC's and the tube swap to a known good tube is a good suggestion. Do you own or have access to a good tube tester?

    Wb
     

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