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USB cable makes a difference shock!

Discussion in 'trade discussion' started by Purité Audio, Feb 6, 2019.

  1. Purité Audio

    Purité Audio Trade: Purite Audio

  2. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    So differences are measurable and do exist. SHOCKING!!!!
     
  3. Purité Audio

    Purité Audio Trade: Purite Audio

    But inaudible.
    Keith
     
    joe9407 likes this.
  4. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    Maybe out of the human hearing range, but what if the deleterious effect is affecting other kit at attached ends?
     
  5. Purité Audio

    Purité Audio Trade: Purite Audio

    It won’t.
    Keith
     
  6. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    Explain how you know that...
     
  7. Purité Audio

    Purité Audio Trade: Purite Audio

    Because the differences are -140dB minimum .
    Keith
     
  8. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    That's nothing to do with what i asked.
     
  9. Purité Audio

    Purité Audio Trade: Purite Audio

    You understand what -140dB means right?
    Keith
     
  10. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    Yes absolutely, don't answer my question with a question.... i'll say it again incase you didn't see it: what if the deleterious effect is affecting other kit at attached ends?
     
  11. narabdela

    narabdela who?


    I think I sense some straws being clutched. Out of range of my hearing though.
     
  12. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    No, no at all, my question has nothing to do with dB rating....

    The test result shows the D-A conversion shows measurable differences @-140db+
    My question is what are the differences causing in the D-D environment? this isn't remotely the same question.
     
  13. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

  14. Marky-Mark

    Marky-Mark pfm Member

    The only kit I can imagine in danger would be someone's credit card.
     
    Emlin, nicetone and lazycat like this.
  15. awkwardbydesign

    awkwardbydesign Officially Awesome

    Whenever I notice Marky-Mark has posted, I just have see what reasoned analysis he has provided this time.
    I just can't help myself. :D
     
  16. AndrewM

    AndrewM pfm Member

    This test shows that the difference in the cables is measurable but below the human hearing threshold. Can you show any test results to show that the difference is audibly affecting other attached kit? If not, yours is a rhetorical question only in the context of this test.
     
  17. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    Thats exactly what I'm asking!!
     
  18. Millennium

    Millennium Active Member

    It's something like Radio 3 and 4 though, so, you know, psu is iffy (lol)
     
  19. thebiglebowski

    thebiglebowski pfm Member

    It has everything to do with dB

    If we assume that the output voltage of a DAC is 2V then the noise at -140dB is (at most)

    0.000000000000002 Volts

    or

    0.2 pV (that is pico which comes after milli, micro and nano)

    Do you think that would be audible (hint - anything below -60 dB is inaudible to the average person) or could possibly have any effect elsewhere?


    If you want to use a digital argument (which really doesn't apply in that test but we'll play along for shits and giggles)

    USB 1.0 uses a signal differential of roughly 3v to represent a 1/0 therefore using a 3v reference -140dB would equal.....

    0.000000000000003 Volts

    or

    0.3 pV

    Even at the highest bandwidth and specific signalling USB 2.0 looks for a differential voltage of 400mV that is 0.4 Volts

    Do you think that either 0.000000003 or 0.0000000004 mV could cause any spurious effects?
     
    Emlin and nicetone like this.
  20. Cereal Killer

    Cereal Killer fourhundredandthirtytwo

    Thanks for the detailed maths on db ratio. I was aking what is happening in the digital to digital domain not in the analog result.
     

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