Rockna Wavelight technical measurements

Discussion in 'Source Measurements' started by atomicbob, Jun 11, 2021.

  1. atomicbob

    atomicbob dScope Yoda

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    Rockna Wavelight technical measurements

    Standard Prologue
    If you are unfamiliar with audio measurements please use a search engine with the query:
    "audio measurements" or "audio measurement handbook"
    Look for publications by Richard C. Cabot and also by Bob Metzler, both from Audio Precision. There are other useful publications as well. These will provide basic knowledge.
    Interpretation of the following measurements is beyond the scope of technical measurements posts.

    The data presented were collected as follows:

    1. PrismSound dScope III, picoscope 5243B, Cal Test CT2593-2 balanced probe
    2. Tecnec 75R AES cable
    3. Balanced XLR cables Belden 1800F with Neutrik 110R AES connectors
    4. Single Ended cables Mogami 2964 1 meter with Amphenol RCA connectors
    5. 100 Kohm load used for measurements
    6. dScope analyzer sample rate 48 KHz unless otherwise noted
    7. DAC 44.1 KHz sample rate, 24 bit depth unless otherwise noted
    8. Audioquest Forest and Schiit Pyst USB cables
    9. Vaunix Lab Brick USB hub
    10. Shielded 14AWG and 16AWG power cables
    11. Lin filter mode unless otherwise noted

    Measurements are made in accordance with AES17:2015

    Rockna Wavelight
    Measurements for record commenced after warmup of at least 168 hours.
    Measurements were performed over a period of two months.
    Many measurements were performed twice, one month apart for consistency verification.

    Index
    Post 1 - measurement setup description, highlights
    Post 2 - AES input - Bal XLR outputs
    Post 3 - AES input - SE RCA outputs
    Post 4 - USB ASIO input - Bal XLR outputs
    Post 5 - USB ASIO input - SE RCA outputs
    Post 6 - Filter response 20 Hz square wave
    Post 6 - Filter response Imaging
    Post 7 - Filter response 20 Hz square wave
    Post 7 - Jitter attenuation
    Post 8 - reserved for additional data and corrections


    Notable highlights:

    NOS filter reponse to 20 Hz square wave has an unusually fast slew rate but also has a very short, peculiar ring which is uncharacteristic for a NOS filter. Estimated transient bandwidth is exceptionally high at 485 KHz with 44 KHz source to AES input.

    Low residual noise spectrum below -123 dBFS.
    Low distortion spectrum with 4+HD+N below -103 dBFS
    Power supply noise spectrum below -145 dBFS in balanced output
    Balanced output Dynamic Range of 125 dB
    Balanced output Cross-talk is close to dual mono with > 100 dB isolation
    Balanced output Gain Linearity is nearly perfect to -115 dBFS, less than ± 2 dB to -125 dBFS
    Exceptionally low jitter with AES input
    Jitter reduction system produced attenuation of 62 ~ 71 dB with 80 nS p-p jitter injected in source stream
    Single Ended performance is somewhat less than Balanced output, as is typical
    Single Ended performance is still excellent compared to other DAC SE outputs

    Excellent design by the Rockna team


    Oddities:
    ASIO driver was problematic for both measurements and listening evaluation.
    ASIO4All + Wavelight windows native driver was used instead.

    I could never get the Wavelight to perform a 44 KHz 16 bit -90 dBFS waveform evaluation using any combination of USB native or ASIO. It always produced a 24 bit smoothed result. The same test ran as expected on the AES measurements with results also as expected.

    While switching between filters and source inputs multiple times with audio playing the DAC output latched to positive supply on several occasions. It was necessary to cycle power to reset. Power cycle needed to be longer than 10 seconds. This happened over a period of two days. In normal use with infrequent changes this issue did not arise.


    Measurement setup picture example:
    DSC_0617_small.jpg

    Listening pictures:
    DSC_0618_small.jpg

    Wavelight has received 200+ listening hours. The Wavelight is an excellent DAC.
    Extensive listening comparisons were made between Rockna Wavelight and Holo Audio KTE Spring2 including ABX testing:
    Rockna Wavelight - Holo Audio Spring2 KTE listening evaluation

    Click on any image in this report to enlarge the image and see fine details
     
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    Last edited: Jun 11, 2021
  2. atomicbob

    atomicbob dScope Yoda

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    AES input Bal output measurements

    Wavelight Dynamic Range AES input Bal output
    20210429 Wavelight dynamic range FFT AES Bal.png

    Dynamic range, in simplified terms
    1. find maximum output voltage at 0 dBFS
    2. find residual noise with a -60 dBFS 1 KHz stimulus, removed from analysis by window notch
    3. Dynamic Range is the difference between maximum output and residual noise
    Specifics are in AES17 section 9.3 (measurebators do your homework please)
    Example here:
    https://www.maximintegrated.com/en/design/blog/spec-dynamic-range.html

    Why we have a -60 dBFS stimulus
    Some clever codec designers include an output gate that shuts off when there is no signal present. This has the dual benefit of lowering output idle noise while also gaming the measurements. AES became wise requiring a -60 dBFS stimulus so any such gates are open during measurement and true Dynamic Range performance measured.


    Wavelight A04 THD+N THD nth-HD FFT AES input Bal output
    20210429 Wavelight A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal 0dBFS - AES.png

    Wavelight 50 + 7000 Hz AES input Bal output - Left Channel
    FFT_2_L1T13_1_A.png

    Wavelight Gain Linearity AES input Bal output - Left Channel
    20210429 Wavelight amplitude linearity FFT AES Bal.png

    Wavelight THD+N vs Frequency AES input Bal output - Left Channel
    G2_L1T5_1_A.png

    Wavelight Residual Noise Bal AES input Bal output - Left Channel
    20210429 Wavelight residual noise FFT AES Bal - 160 dB range.png

    Complete AES input Bal output analysis report pdf attached
     

    Attached Files:

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  3. atomicbob

    atomicbob dScope Yoda

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    AES input SE output measurements

    Wavelight Dynamic Range AES input Bal output
    20210526 Wavelight dynamic range FFT AES SE.png

    Wavelight A04 THD+N THD nth-HD FFT AES input SE output
    20210526 Wavelight A04 THD+N THD nth-HD 4+HD+N 60Hz FFT SE 0dBFS - AES.png

    Wavelight 50 + 7000 Hz AES input SE output - Left Channel
    FFT_2_L1T13_1_A.png

    Wavelight Gain Linearity AES input SE output - Left Channel
    20210526 Wavelight amplitude linearity FFT AES SE.png

    Wavelight THD+N vs Frequency AES input SE output - Left Channel
    G2_L1T5_1_A.png

    Wavelight Residual Noise AES input SE output - Left Channel
    20210526 Wavelight residual noise FFT AES SE - 160 dB range.png

    Complete AES input SE output analysis report pdf attached
     

    Attached Files:

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  4. atomicbob

    atomicbob dScope Yoda

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    USB ASIO input Bal output measurements

    Wavelight Dynamic Range USB input Bal output
    20210526 Wavelight dynamic range FFT USB Bal.png

    Wavelight A04 THD+N THD nth-HD FFT USB input Bal output
    20210526 Wavelight A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal 0dBFS - USB.png

    Wavelight 50 + 7000 Hz USB input Bal output - Left Channel
    FFT_2_L1T13_1_A.png

    Wavelight Gain Linearity USB input Bal output - Left Channel
    20210526 Wavelight amplitude linearity FFT USB Bal.png

    Wavelight THD+N vs Frequency USB input Bal output - Left Channel
    G2_L1T5_1_A.png

    Wavelight Residual Noise Bal USB input Bal output - Left Channel
    20210526 Wavelight residual noise FFT USB Bal - 160 dB range.png

    Complete USB input Bal output analysis report pdf attached
     

    Attached Files:

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  5. atomicbob

    atomicbob dScope Yoda

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    USB ASIO input SE output measurements

    Wavelight Dynamic Range USB input Bal output
    20210526 Wavelight dynamic range FFT USB SE.png

    Wavelight A04 THD+N THD nth-HD FFT USB input SE output
    20210526 Wavelight A04 THD+N THD nth-HD 4+HD+N 60Hz FFT SE 0dBFS - USB.png

    Wavelight 50 + 7000 Hz USB input SE output - Left Channel
    FFT_2_L1T13_1_A.png

    Wavelight Gain Linearity USB input SE output - Left Channel
    20210526 Wavelight amplitude linearity FFT USB SE t2.png

    Wavelight THD+N vs Frequency USB input SE output - Left Channel
    G2_L1T5_1_A.png

    Wavelight Residual Noise USB input SE output - Left Channel
    20210526 Wavelight residual noise FFT USB SE - 160 dB range.png

    Complete USB input SE output analysis report pdf attached
     

    Attached Files:

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  6. atomicbob

    atomicbob dScope Yoda

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    Filter Response 20 Hz square wave

    Measurement conditions
    1. -3 dBFS 20Hz square wave
    2. 44.1 KHz sample rate
    3. USB ASIO input
    4. Bal output to oscilloscope using CT2593-2 balanced probe

    Filter response measured the same across source inputs and Bal SEoutputs

    Characteristic square wave response

    Wavelight 2.5mS/div Lin
    20210429-1 SigGen Wavelight 20 Hz square -3dBFS 2_5mS div 5MHz filter AES Bal BW calc Lin.png

    Wavelight 2.5mS/div Min
    20210429-2 SigGen Wavelight 20 Hz square -3dBFS 2_5mS div 5MHz filter AES Bal BW calc Min.png

    Wavelight 2.5mS/div Hybrid
    20210429-3 SigGen Wavelight 20 Hz square -3dBFS 2_5mS div 5MHz filter AES Bal BW calc HYB.png

    Wavelight 2.5mS/div NOS
    20210429-4 SigGen Wavelight 20 Hz square -3dBFS 2_5mS div 5MHz filter AES Bal BW calc NOS.png
    Note the unusual spike (very short ring) on each transition


    Detailed examination

    Why square wave observations are typically made at -3 dBFS
    Wavelight 5uS/div Lin at 0 dBFS
    20210429-1 SigGen Wavelight 20 Hz square 0dBFS 5uS div 5MHz filter AES Bal BW calc Lin.png
    Note clipping of the filter ring - vertical range ± 20V

    Wavelight 5uS/div Lin at -3 dBFS
    20210429-2 SigGen Wavelight 20 Hz square -3dBFS 5uS div 5MHz filter AES Bal BW calc Lin.png
    Filter ring no longer clipped - vertical range expanded to ± 10V

    Wavelight 5uS/div Lin BW calculation
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 18.4 uS = 19.0 KHz

    Wavelight 10uS/div Min at -3 dBFS
    20210429-3 SigGen Wavelight 20 Hz square -3dBFS 10uS div 5MHz filter AES Bal BW calc Min.png
    Wavelight 10uS/div Min BW calculation
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 35.44 uS = 9.88 KHz

    Wavelight 10uS/div Hybrid at -3 dBFS
    20210429-4 SigGen Wavelight 20 Hz square -3dBFS 10uS div 5MHz filter AES Bal BW calc HYB.png
    Wavelight 10uS/div Hybrid BW calculation
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 18.47 uS = 18.95 KHz

    Wavelight 500nS/div NOS at 0 dBFS
    20210429-5 SigGen Wavelight 20 Hz square 0dBFS 500nS div 5MHz filter AES Bal BW calc NOS.png
    Wavelight 500nS/div NOS BW calculation
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 721.4 nS = 485 KHz

    The oscilloscope traces above reveal steps in the transitions that would imply we are observing the output of a Sample and Hold without any additional low pass filtering.
     
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  7. atomicbob

    atomicbob dScope Yoda

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    Filter Response Imaging

    Wavelight Imaging AES input Bal output Lin filter
    20210429 Wavelight imaging FFT AES Bal - Lin.png

    Wavelight Imaging AES input Bal output Min filter
    20210429 Wavelight imaging FFT AES Bal - Min.png

    Wavelight Imaging AES input Bal output Hybrid filter
    20210429 Wavelight imaging FFT AES Bal - Hyb.png

    Wavelight Imaging AES input Bal output NOS filter
    20210429 Wavelight imaging FFT AES Bal - NOS.png

    Wavelight Imaging AES input Bal output filter comparison
    20210429 Wavelight imaging FFT AES Bal - ALL.png

    Wavelight Lin, Min and Hybrid filter imaging are unusually consistent between modes than most DACs


    Jitter Attenuation

    Wavelight has a jitter reduction system which produced 71 dB of jitter attenuation
    20210527 Wavelight jitter attenuation AES 44K Bal 17dBu.png
     
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  8. atomicbob

    atomicbob dScope Yoda

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    reserved for additional data and corrections
     

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