Grant Fidelity TubeDAC-11 Problem

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

  1. philviral

    philviral Active Member

    Messages:
    395
    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:
    1,573
    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:
    395
    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:
    395
    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:
    1,573
    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
     
  8. philviral

    philviral Active Member

    Messages:
    395
    Location:
    London, Ontario
    I do not have access to a tube tester of any kind. I did swap the tube though - made no change.
     
  9. mroboto

    mroboto Super Member

    Messages:
    1,573
    I too now have a problem with my TubeDAC-11, faint and distorted sound on left channel, the right side is ok, swap the tube didn't fix the issue.

    There is relays in it, and relays are often prone to become only partially conductive, noisy, I don't know the exact functions of the relays, I must investigate and maybe replace them.

    For now, I use my USB DAC http://audiokarma.org/forums/index....02a-asynchronous-32bit-384khz-usb-dac.835889/
     
  10. rwartner

    rwartner Super Member

    Messages:
    1,195
    Location:
    Scottsdale, AZ
    I have a Maverick tube DAC which is similar. I tend to set and forget. Discovered cleaning the volume control once in a while is a good thing.
     
  11. mroboto

    mroboto Super Member

    Messages:
    1,573
    My problem was the tube pins that was not straight and bad contact, I bought a tube pin straightener from Riverstone Audio and that seems to fix the issue.

    @philviral Have you found what hapens tou yours ?
     

     

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  12. LexDM3

    LexDM3 AK Subscriber Subscriber

    Messages:
    1,730
    Location:
    Arlington, MA
    I have two TD11’s and have noticed that the right channel tends to get quieter or sometimes a bit distorted at times. It turns out to be the volume control. Rotating it a few times seems to be a good temporary fix. I should open both of them up and DeOxit that pot.
     
  13. lbcgav

    lbcgav AK Subscriber Subscriber

    Messages:
    893
    Location:
    Arcadia, CA
    I noticed some scratchiness in the volume pot of my TD11. No distortion, though. Several turns always fixed it, though.
     
  14. mroboto

    mroboto Super Member

    Messages:
    1,573
    I sometimes use a generic Cleaner & Lubricant for light cleaning, Caig Deoxit D5 or D100 for strong cleaning and Caig Faderlube F100 for lube.
     

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