Rockna Wavelight DAC Measurements

Discussion in 'Source Measurements' started by purr1n, Nov 4, 2020.

  1. purr1n

    purr1n Finding his inner redneck

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    Synopsis: Measurements of steady state signals indicate of a certain type of R2R design. Low level signals are impressive. The steady state measurement results at higher output levels are not earth shattering, but they confirm nothing is wrong, and are more than good enough to not have any bearing on subjective sound quality.

    Rockna Wavelight DAC
    1kHz sine 0dbFS
    upload_2020-11-4_14-3-55.png

    Rockna Wavelight DAC
    1kHz sine
    -10dbFS
    upload_2020-11-4_14-5-22.png

    -30dbFS
    upload_2020-11-4_14-6-1.png

    -60dbFS
    upload_2020-11-4_14-6-36.png

    -90dbFS
    upload_2020-11-4_14-7-35.png
     
    Last edited: Nov 4, 2020
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  2. purr1n

    purr1n Finding his inner redneck

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    Rockna Wavelight DAC
    1kHz sine
    THDN vs dbFS
    upload_2020-11-4_14-19-17.png
     
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  3. purr1n

    purr1n Finding his inner redneck

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    Rockna Wavelight DAC
    600+1.7kHz dual sine
    upload_2020-11-4_14-23-25.png
     
    Last edited: Nov 4, 2020
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  4. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    I'd say that the harmonic structure is even more agreeable than the one on Wavedream.
     
  5. Clemmaster

    Clemmaster Friend

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    Will you measure the pre-amp, too?
     
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  6. purr1n

    purr1n Finding his inner redneck

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    Rockna Wavelight DAC
    19+20kHz dual sine
    upload_2020-11-4_15-5-24.png
     
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  7. purr1n

    purr1n Finding his inner redneck

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    JTEST 44.1kHz 24-bit
    (the grass is supposed to be there in the JTEST signal)
    upload_2020-11-4_15-8-53.png
     
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  8. purr1n

    purr1n Finding his inner redneck

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    Linear phase filter vs NOS
    upload_2020-11-4_15-19-29.png
     
  9. purr1n

    purr1n Finding his inner redneck

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    Linear phase white noise 44.1kHz
    upload_2020-11-4_15-22-22.png

    NOS white noise 44.1kHz
    upload_2020-11-4_15-20-10.png
     
    Last edited: Nov 5, 2020
  10. purr1n

    purr1n Finding his inner redneck

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    Trying to get it to work...
     
  11. purr1n

    purr1n Finding his inner redneck

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    Not sure if any of this really tells us anything. All the distortion and grass is over 80db to 100db down. The pattern does seem more agreeable since Wavedream has more evident odd order. One very interesting behavior with the Wavelight is how the harmonics disappear at lower signal levels. AC mains filtering is better on Wavelight too, but again all this stuff is 100db down. No one gonna hear this and if there are sonic differences, it won't be found in these simplistic steady state signals.
     
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  12. penguins

    penguins Friend, formerly known as fp627

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    Just curious - Is there speculation as to why there is still a spike at 1khz for the 19+20khz dual input? Seems a little odd for a random harmonic to occur that far down at exactly 1k although I agree that practically speaking -100dB down is nothing to worry about (at least for my ears).

    Also NOS measurement confirms one of the reasons why I liked this NOS mode more than some other NOS I've heard in the short listen I had - it's not as dramatic / significant of a drop off in terms of "quantity". Granted subjective stuff not shown, etc.
     
  13. soekris

    soekris MOT - Soekris Engineering

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    Those measurements are typical of a Sign Magnitude R-2R DAC.... I see about the same on my DACs.
     
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  14. Baten

    Baten Friend

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    Not to derail, but looking forward how the new dac2541 will perform ;)
     
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  15. purr1n

    purr1n Finding his inner redneck

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    Yes. It would appear that Rockna went to sign magnitude with the Wavelight. The Wavedream did not appear to be a sign magnitude R2R.

    Intermodulation distortion. 20kHz - 19kHz = 1kHz. The 1kHz then combines with the 19kHz and 20kHz to produce sidebands at 18kHz and 21kHz. More of a curiosity. The IMD is too low for humans to make anything of it.

    I'll do a wideband multitone measurement in a bit.
     
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  16. purr1n

    purr1n Finding his inner redneck

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    On the IMD, one of these days, I will put together a multitone test with characteristics of real music, like this:

    Drat Punk, Doin; It Right
    Frequency and Amplitude Analysis
    YEL = peak, RED = geometric mean
    [​IMG]

    From this, we can see that the suite of measurement typically conducted are not reflective of actual music. Too much focus on 0dbFS sine waves, which NEVER occur. A 0dbFS sine wave measurement is really an academic curiosity. It might tell us a few things, maybe. Note that a 0dbFS sine wave in encoded digital codewords has NO MORE room for any additional signals, at least not without distortion. This is why the peaks in real music at any one particular frequency never hit 0dbFS.

    Finally, a floor 100db below full-scale may be appropriate. Microphones with microphone preamps on a good day in ideal circumstances will hit 85db SNR. The 16-bit limit is 96db. It would be worth it sometime in the future to analyze content, decimate the bits, to see how many bits are actually music and how many are actually noise. Extra bits is nice for digital production, mixing, etc. but not necessary for home reproduction. Let's be conservative and add two bits to the 16 for 18 bits. 96db + 2 x 6db = 108db. So let's set the floor to -108db, knowing that there will probably not be any music content in the last few least significant bits.

    The only thing I would modify below is adjust the signal levels at each frequency to match profiles of music (EDM, classical, rock, jazz, hip hop etc.)

    Rockna Wavelight
    Multitone Test
    upload_2020-11-5_8-58-28.png

    Does this mean the Wavelight doesn't have a sound signature and is "fully transparent"? Nope. It only means these tests comprised of steady-state signals are next to worthless in telling us anything (other that something is amiss). We already know that we can easily tell the difference among the so-called "state-of-the-art" 0.000x% amplifiers between A90, Magnius, Heresy, THX, etc. Anyone who tells you they don't sound different is lying to you. They either have not conducted level-matched blind tests themselves, have conducted tests in such a way to ensure they failed, or are deaf.

    Note that even the great audio scientist Amir couldn't even even hear the extremely crappy SINAD (high levels of odd order harmonics too) of the plate amp from the JBL LSR305, a product he gave the highest recommendation to! The fact is, audio objectivists bitch about "high" distortion, euphonic or otherwise, but they really can't hear any of this stuff.
     
    Last edited: Nov 5, 2020
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  17. Clemmaster

    Clemmaster Friend

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    The App works much better on Android than iOS, FWIW.
     

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