I have found an improvement in SQ between my two digital music sources

Discussion in 'Digital Sources' started by Bill Ferris, Jun 5, 2018.

  1. olson_jr

    olson_jr AK Subscriber Subscriber

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  2. botrytis

    botrytis Trying not to be a Small Speaker Hoarder Subscriber

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    The point being is you want more power than is needed, just like with PS in Amplifiers, etc. The less the PS is stressed, the less noise. 350 watt is great if you are running a laptop CPU and not much else but when you have a CPU that can draw 125 to 200 watts by itself and a video card that also pulls 250 watts, that little 350 watt PS is being pushed to it's max. That is the reason I won't use Dell or any other prebuilt desktop for a music server. I don't know why people think computers are any different. I guess computers must follow different laws of physics.

    I am using a mini-PC with a 15 watt CPU and an SSD for a Daphile system. The PS in that one is a 300 watt unit and that is more than enough.
     
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  3. E-Stat

    E-Stat AK Subscriber Subscriber

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    Inherent noise.
     
  4. cpt_paranoia

    cpt_paranoia Well-Known Member

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    The level of noise isn't obvious. It depends on many factors; PSU, cabling, driver, filtering, etc.
     
  5. botrytis

    botrytis Trying not to be a Small Speaker Hoarder Subscriber

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    :thumbsup::thumbsup::thumbsup:

    EXACTLY - the more stress on the PS of a computer the more noise you get. Better PS's also have better grounding less noise, etc. Why would music data be any different that regular data? Noise corrupts both and one is not more inherently more susceptible than the other. You build a decent PC, the noise floor is low to begin with.
     
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  6. E-Stat

    E-Stat AK Subscriber Subscriber

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    Unless you're using a linear, that's simply note true. Switch mode power supplies are inherently noisy.

    My desktop isn't stressed at all. Here's the math:

    The i7-860 draws 85 watts at idle and averages 150. Nvidia GT740 video card draws 64. Samsung EVO 850 SSD draws 30 mW. Seagate Barracuda drive draws 5.

    Your components must be real power hogs!
     

     

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  7. E-Stat

    E-Stat AK Subscriber Subscriber

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    The topic to which my responses in posts 10,13 and 17 refers is the USB interface.
     
  8. cpt_paranoia

    cpt_paranoia Well-Known Member

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    The difference between 'regular data' and 'music data' is that noise on the music data connection can couple into the analogue domain. Noise on a word file doesn't couple into the word document. In both cases, we assume perfect digital data transmission, so data bit corruption is not an issue (there are mechanisms to detect and correct errors, too). If you have residual bit errors, then you have bigger things to worry about...

    The trick with digital to analogue data streams is to stop noise on the digital signal coupling into the analogue domain. That noise can be carried by electrical means, or timing means.
     
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  9. botrytis

    botrytis Trying not to be a Small Speaker Hoarder Subscriber

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    Most decent NAME BRAND MB's have filtering on the USB power input. MB's in the DELL, etc. do not. You are missing the point also. There is inherent noise in the S/PDIF system that has never been addressed as the chips used are of an older design and SYNCHRONOUS in nature. So, even if the DAC chip has reclocking and filtering built in, the S/PDIF input bypasses that. That means if the bits go wonky in transmission, you have junk and noise. There are plenty of articles on that out there.

    The USB input on the DAC needs to be MORE than just a DAC input chip but the same can be said for any input.
     
  10. cpt_paranoia

    cpt_paranoia Well-Known Member

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    And the USB interface involves PSU, cabling, driver and filtering.
     
  11. botrytis

    botrytis Trying not to be a Small Speaker Hoarder Subscriber

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    It can - especially in scientific instrumentation where the dats is based on measured voltages and noise adds to that which can cause issues with those measurements.. What you are saying is that MUSIC DATA is special. It is not. Treat all digital data the same way, that is what I am saying.
     

     

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  12. E-Stat

    E-Stat AK Subscriber Subscriber

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    Each can serve to ameliorate the inherently noisy interface, yes.
     
  13. botrytis

    botrytis Trying not to be a Small Speaker Hoarder Subscriber

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    It can - especially in scientific instrumentation where the dats is based on measured voltages and noise adds to that which can cause issues with those measurements.. What you are saying is that MUSIC DATA is special. It is not. Treat all digital data the same way, that is what I am saying.
     
  14. EngineerNate

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    The real question is how is any of the noise present making it through the USB connection, which is all digital (So noise is irrelevant unless it's so bad that it's breaking up the recognition of the data) all the way to the analog chain. Regardless of the noise present internally to the PC, it has to get into the analog side of the DAC somewhere for it to cause an audible problem. So either:

    1. Noise on the digital side is affecting the actual digital-to-analog process. In which case it seems there is insufficient filtering on the input side of the DAC chip or something is seriously askew in the signal to noise ratio there. Especially with an asynchronous USB protocol that's reclocking the data at the DAC, this seems unlikely.

    2. Noise from the PSU is simply making it into the analog preamp circuitry inside the DAC. Which indicates improper filtering on the PSU side of the DAC. Is the DAC running off of it's own power supply when using SPDIF and off of USB power when using USB as the input? This could account for some of the difference. I wonder if a USB data-only cable could be created to isolate the PC's power from the DAC.

    Either way, it's a failing in the DAC design. Noise in the USB power/signal should be accounted for during the design process of the DAC.
     
  15. E-Stat

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    I don't have any interest driving a DAC directly from a computer's USB port. I want the computer (and its SMPS) as far away from the renderer as possible.
     
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  16. EngineerNate

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    What protocol provides an improvement in performance over an asynchronous USB connection? SPDIF/Optical has issues with both jitter and ability to transmit better formats (DSD is quite limited over SPDIF for example).
     

     

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  17. E-Stat

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    If your comment is addressed to me, return to post # 10 and follow the link.
     
  18. EngineerNate

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    It was a general comment, but thanks.

    That's still USB and if the DAC is running in asynchronous mode and doing it's own internal clock regen... unless something is going very wrong I have my doubts that said product makes an audible difference, or at least, one more audible than something like the Schiit Wyrd, which I also find to be a dubiously useful product.

    If USB is clean enough for the professionals to record the source material with... well.
     
  19. E-Stat

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    Who said otherwise? I merely observe that the best audio players provide signal regeneration for optimum performance.

    Feel free to speculate as you will.
     
  20. EngineerNate

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    It's less speculation and more skepticism. Comes with the profession. In a way internal reclocking at the DAC is a form of signal regeneration so we're in agreement there. I'm mostly skeptical that regenerating it twice is useful. That device is pretty much doing what the DAC is doing already, if, as I said, it's running in asynchronous mode. Reclocking is an inherent part of that process.

    I wonder if any USB 2.0 or USB 3.0 capable opto-isolators are available. That'd basically knock out any noise from getting through on the signal part of the USB and could be done for $10-15 bucks.
     

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