Soekris dac1541 technical measurements

Discussion in 'Source Measurements' started by atomicbob, Aug 18, 2017.

  1. atomicbob

    atomicbob dScope Yoda

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    Please Note - 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 this post.


    Soekris dac 1541

    The data presented were acquired as follows:


    1. PrismSound dScope III, picoscope 5243B
    2. DAC unbalanced SE RCA and balanced BAL output XLR
    3. 100 Kohm load used for measurements
    4. 44.1 KHz sample rate, 24 bit depth most measurements unless otherwise noted
    5. USB input – Audioquest Forest
    6. SPDIF input - Tecnec 75 ohm SMPTE 259M/292M Digital Broadcast Cable
    7. Unbalance RCA cable - Worlds Best Cable Gotham GAC-2 or DH Labs Silver Sonic Air Matrix
    8. Balanced XLR cable - Canare L-4E6S starquad with Neutrik XLR connectors
    9. Vaunix Lab Brick USB hub
    10: Shielded 14AWG and 16AWG power cables

    The matrix of data for a specific measurement (typical but not always):

    Measurement name – Bal - spdif
    Measurement name – Bal - USB WDM
    Measurement name – Bal - USB ASIO
    Measurement name – SE - spdif
    Measurement name – SE - USB WDM
    Measurement name – SE - USB ASIO
    Measurement name – HP - USB WDM – 30R
    Measurement name – HP - USB WDM – 300R

    Where:

    Bal = Balanced XLR DAC output
    SE = Single Ended RCA DAC output
    HP = Headphone 4-pin Neutrik connector
    30R = 30 ohm load
    300R = 300 ohm load

    This DAC has the following filter modes available:

    Lin – Linear phase
    Mix – Mix between Linear and Minimum
    Min – Minimum phase
    Soft – Soft minimum phase, Butterworth

    Unless specifically noted, Lin filter mode was used. Most of the measurements are substantially similar between Lin, Min and Max. The Soft filter mode did have an effect on many measurements presented. One set of Single Ended (SE) measurements was performed on all filter types to demonstrate how substantially similar they are. Thus only Lin and where appropriate Soft filter measurements are posted to save space and time. Mix was used on HP measurements.


    To reiterate:

    DAC output measurements were typically performed with Lin filter.
    HP output measurements were typically performed with the Mix filter.
    Certain measurements exercised each of the filters (20 Hz square wave)
    Measurements were performed after 72 hrs of DAC power on time.

    Graph titles use the abbreviations noted above and are somewhat cryptic but should be identifiable.


    Notable highlights:

    Single Ended outputs measure better than balanced in some attributes such as jitter residual spectrum. Most unexpected. The measurements were repeated multiple times and diagnostics undertaken with results remaining consistent with first measurements. To put into context, if the jitter residual spectrum were measured as Distortion + Noise the following is observed in these graphs:

    Balanced output Jitter residual Distortion + Noise: 0.000251% Excellent
    Single Ended output Jitter residual Distortion + Noise: 0.000010% Phenominal
    Well done @soekris !

    Native USB implementation is quite good with jitter spectrum lower than spdif input. Eitr usage results in same jitter as from dScope spdif direct. This suggests the Soekris dac1541 will perform well on internal (native) USB and may not benefit from Eitr as a DDC.

    I enjoyed listening to this compact DAC-HP Amp between measurement sets.

    Setup picture:
    DSC_0505a.jpg

    Index

    Topic - Post Number
    00 Introduction - 1
    01 frequency response - 2, 3
    02 THD+N vs frequency - 4
    03 THD+N vs amplitude - 5
    04 IMD spectrum - 6, 7
    05 IMD vs amplitude - 8
    06 dynamic range - 9
    07 1 KHz -90 dBFS - 9
    08 gain linearity - 10
    09 dual tones - 11, 12, 13
    10 imaging - 14, 15
    11 crosstalk - 16
    12 jitter - 16
    13 sqr wave response - 17, 18
    14 27 bit resolution - 19, 20
     
    Last edited: Aug 31, 2017
  2. atomicbob

    atomicbob dScope Yoda

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    01a Frequency Response

    01 Bal FR All four filter modes - spdif
    Min = Blue
    Lin = Red
    Mix = Green
    Soft = Yellow
    01 Bal FR All - spdif.PNG

    02 Bal FR All four filter modes - WDM
    02 Bal FR All - WDM.PNG

    03 SE FR All four filter modes - spdif
    03 SE FR All - spdif.PNG

    04 SE FR All four filter modes - WDM
    04 SE FR All - WDM.PNG

    05 Bal FR Mix 30R
    05 Bal FR Mix 30R.PNG

    06 Bal FR Mix 300R
    06 Bal FR Mix 300R.PNG

    07 Bal FR Y axis zoomed All - spdif
    07 Bal FR Y axis zoomed All - spdif.PNG

    08 Bal FR Y axis zoomed All - WDM
    08 Bal FR Y axis zoomed All - WDM.PNG

    09 SE FR Y axis zoomed All - spdif
    09 SE FR Y axis zoomed All - spdif.PNG

    10 SE FR Y axis zoomed All - WDM
    10 SE FR Y axis zoomed All - WDM.PNG

     
    Last edited: Aug 29, 2017
  3. atomicbob

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    01b Frequency Response

    11 Bal FR Y axis highly zoomed All - spdif
    11 Bal FR Y axis highly zoomed All - spdif.PNG

    12 Bal FR Y axis highly zoomed All - WDM
    12 Bal FR Y axis highly zoomed All - WDM.PNG

    13 SE FR Y axis highly zoomed All - spdif
    13 SE FR Y axis highly zoomed All - spdif.PNG

    14 SE FR Y axis highly zoomed All - WDM
    14 SE FR Y axis highly zoomed All - WDM.PNG

    15 Bal FR Y axis highly zoomed Mix 30R
    15 Bal FR Y axis highly zoomed Mix 30R.PNG

    16 Bal FR Y axis highly zoomed Mix 300R
    16 Bal FR Y axis highly zoomed Mix 300R.PNG

     
    Last edited: Aug 18, 2017
  4. atomicbob

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    02 THD+N vs frequency


    01 Bal THD THD+N - spdif
    01 Bal THD THD+N - spdif.PNG

    02 Bal THD THD+N - WDM t2
    02 Bal THD THD+N - WDM t2.PNG

    03 Bal THD THD+N - ASIO
    03 Bal THD THD+N - ASIO.PNG

    04 SE THD THD+N - spdif
    04 SE THD THD+N - spdif.PNG

    05 SE THD THD+N - WDM
    05 SE THD THD+N - WDM.PNG

    06 SE THD THD+N - ASIO
    06 SE THD THD+N - ASIO.PNG

    07 Bal THD THD+N 0dBu 30R
    07 Bal THD THD+N 0dBu 30R.PNG

    08 Bal THD THD+N 0dBu 300R
    08 Bal THD THD+N 0dBu 300R.PNG


     
    Last edited: Aug 18, 2017
  5. atomicbob

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    03 THD+N vs amplitude

    01 Bal THD THD+N vs amplitude - spdif
    01 Bal THD THD+N vs amplitude - spdif.PNG

    02 Bal THD THD+N vs amplitude - WDM
    02 Bal THD THD+N vs amplitude - WDM.PNG

    03 SE THD THD+N vs amplitude - spdif
    03 SE THD THD+N vs amplitude - spdif.PNG

    04 SE THD THD+N vs amplitude - WDM
    04 SE THD THD+N vs amplitude - WDM.PNG

    05 Bal THD THD+N vs amplitude 30R
    05 Bal THD THD+N vs amplitude 30R.PNG

    06 Bal THD THD+N vs amplitude 300R
    06 Bal THD THD+N vs amplitude 300R.PNG


     
    Last edited: Aug 18, 2017
  6. atomicbob

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    04a IMD spectrum

    01 Bal IMD spectrum - spdif
    01 Bal IMD spectrum - spdif.PNG

    02 Bal IMD spectrum - WDM
    02 Bal IMD spectrum - WDM.PNG

    03 Bal IMD spectrum - ASIO
    03 Bal IMD spectrum - ASIO.PNG

    04 SE IMD spectrum - spdif
    04 SE IMD spectrum - spdif.PNG

    05 SE IMD spectrum - WDM
    05 SE IMD spectrum - WDM.PNG

    06 SE IMD spectrum - ASIO
    06 SE IMD spectrum - ASIO.PNG

    07 Bal IMD spectrum 30R
    07 Bal IMD spectrum 30R.PNG

    08 Bal IMD spectrum 300R
    08 Bal IMD spectrum 300R.PNG

     
    Last edited: Aug 18, 2017
  7. atomicbob

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    04b IMD spectrum

    10 Bal IMD spectrum Soft - WDM
    10 Bal IMD spectrum Soft - WDM.PNG

    11 Bal IMD spectrum Soft - ASIO
    11 Bal IMD spectrum Soft - ASIO.PNG

    12 SE IMD spectrum Soft - WDM
    12 SE IMD spectrum Soft - WDM.PNG

    13 SE IMD spectrum Soft - ASIO
    13 SE IMD spectrum Soft - ASIO.PNG

    14 SE IMD spectrum Soft -1 dBFS - WDM
    14 SE IMD spectrum Soft  -1 dBFS - WDM.PNG

    15 SE IMD spectrum Soft -2 dBFS - ASIO
    15 SE IMD spectrum Soft -2 dBFS - ASIO.PNG

    16 Bal IMD spectrum Soft 30R
    16 Bal IMD spectrum Soft 30R.PNG

    17 Bal IMD spectrum Soft 300R
    17 Bal IMD spectrum Soft 300R.PNG


     
    Last edited: Aug 18, 2017
  8. atomicbob

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    05 IMD vs amplitude

    01 Bal IMD - spdif
    01 Bal IMD - spdif.PNG

    02 Bal IMD - WDM
    02 Bal IMD - WDM.PNG

    03 Bal IMD - ASIO
    03 Bal IMD - ASIO.PNG

    04 SE IMD - spdif
    04 SE IMD - spdif.PNG

    05 SE IMD - WDM
    05 SE IMD - WDM.PNG

    06 SE IMD - ASIO
    06 SE IMD - ASIO.PNG

    07 Bal IMD 30R
    07 Bal IMD 30R.PNG

    08 Bal IMD 300R
    08 Bal IMD 300R.PNG


     
    Last edited: Aug 18, 2017
  9. atomicbob

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    06 dynamic range and 07 1 KHz -90 dBFS sine

    01 Bal dynamic range - spdif
    01 Bal dynamic range - spdif.PNG

    02 Bal dynamic range - WDM
    02 Bal dynamic range - WDM.PNG

    03 SE dynamic range - spdif
    03 SE dynamic range - spdif.PNG

    04 SE dynamic range - WDM
    04 SE dynamic range - WDM.PNG

    05 Bal dynamic range 30R
    05 Bal dynamic range 30R.PNG

    06 Bal dynamic range 300R
    06 Bal dynamic range 300R.PNG


    01 Bal 1 KHz -90 dBFS - spdif
    01 Bal 1 KHz -90 dBFS - spdif.PNG

    02 Bal 1 KHz -90 dBFS - WDM
    02 Bal 1 KHz -90 dBFS - WDM.PNG

    03 SE 1 KHz -90 dBFS - spdif
    03 SE 1 KHz -90 dBFS - spdif.PNG

    04 SE 1 KHz -90 dBFS - WDM
    04 SE 1 KHz -90 dBFS - WDM.PNG


     
    Last edited: Aug 18, 2017
  10. atomicbob

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    08 gain linearity

    01 Bal 1 KHz gain linearity - spdif
    01 Bal 1 KHz gain linearity - spdif.PNG

    02 Bal 1 KHz gain linearity - WDM
    02 Bal 1 KHz gain linearity - WDM.PNG

    03 SE 1 KHz gain linearity - spdif
    03 SE 1 KHz gain linearity - spdif.PNG

    04 SE 1 KHz gain linearity - WDM
    04 SE 1 KHz gain linearity - WDM.PNG

    05 Bal 1 KHz gain linearity 30R
    05 Bal 1 KHz gain linearity 30R.PNG

    06 Bal 1 KHz gain linearity 300R
    06 Bal 1 KHz gain linearity 300R.PNG

     
    Last edited: Aug 18, 2017
  11. atomicbob

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    09a dual tones

    50+7000Hz

    01 Bal 50+7000Hz dual tone - spdif
    01 Bal 50+7000Hz dual tone - spdif.png

    02 Bal 50+7000Hz dual tone - WDM
    02 Bal 50+7000Hz dual tone - WDM.png

    03 SE 50+7000Hz dual tone - spdif
    03 SE 50+7000Hz dual tone - spdif.png

    04 SE 50+7000Hz dual tone - WDM
    04 SE 50+7000Hz dual tone - WDM.png

    05 Bal 50+7000Hz dual tone 30R
    05 Bal 50+7000Hz dual tone 30R.png

    06 Bal 50+7000Hz dual tone 300R
    06 Bal 50+7000Hz dual tone 300R.png

    07 Bal 50+7000Hz dual tone Soft - spdif
    07 Bal 50+7000Hz dual tone Soft - spdif.png

    08 Bal 50+7000Hz dual tone Soft - WDM
    08 Bal 50+7000Hz dual tone Soft - WDM.png

     
    Last edited: Aug 18, 2017
  12. atomicbob

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    09b dual tones

    09 SE 50+7000Hz dual tone Soft - spdif
    09 SE 50+7000Hz dual tone Soft - spdif.png

    10 SE 50+7000Hz dual tone Soft - WDM
    10 SE 50+7000Hz dual tone Soft - WDM.png

    11 Bal 50+7000Hz dual tone Soft 30R
    11 Bal 50+7000Hz dual tone Soft 30R.png

    12 Bal 50+7000Hz dual tone Soft 300R
    12 Bal 50+7000Hz dual tone Soft 300R.png


    600+1700Hz

    01 Bal 600+1700Hz dual tone - spdif
    01 Bal 600+1700Hz dual tone - spdif.png

    02 Bal 600+1700Hz dual tone - WDM
    02 Bal 600+1700Hz dual tone - WDM.png

    03 SE 600+1700Hz dual tone - spdif
    03 SE 600+1700Hz dual tone - spdif.png

    04 SE 600+1700Hz dual tone - WDM
    04 SE 600+1700Hz dual tone - WDM.png

     
    Last edited: Aug 18, 2017
  13. atomicbob

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    09c dual tones

    05 Bal 600+1700Hz dual tone 30R
    05 Bal 600+1700Hz dual tone 30R.png

    06 Bal 600+1700Hz dual tone 300R
    06 Bal 600+1700Hz dual tone 300R.png

    07 Bal 600+1700Hz dual tone Soft - spdif
    07 Bal 600+1700Hz dual tone Soft - spdif.png

    08 Bal 600+1700Hz dual tone Soft - WDM
    08 Bal 600+1700Hz dual tone Soft - WDM.png

    09 SE 600+1700Hz dual tone Soft - spdif
    09 SE 600+1700Hz dual tone Soft - spdif.png

    10 SE 600+1700Hz dual tone Soft - WDM
    10 SE 600+1700Hz dual tone Soft - WDM.png

    11 Bal 600+1700Hz dual tone Soft 30R
    11 Bal 600+1700Hz dual tone Soft 30R.png

    12 Bal 600+1700Hz dual tone Soft 300R
    12 Bal 600+1700Hz dual tone Soft 300R.png


     
    Last edited: Aug 18, 2017
  14. atomicbob

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    10a imaging

    01 SE imaging Lin spdif
    01 SE imaging Lin spdif.PNG

    02 SE imaging Mix - spdif
    02 SE imaging Mix - spdif.PNG

    03 SE imaging Min - spdif
    03 SE imaging Min - spdif.PNG

    04 SE imaging Soft - spdif
    04 SE imaging Soft - spdif.PNG

    05 SE imaging Lin - WDM
    05 SE imaging Lin - WDM.PNG

    06 SE imaging Soft - WDM
    06 SE imaging Soft - WDM.PNG
     
    Last edited: Aug 18, 2017
  15. atomicbob

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    10b imaging

    11 Bal imaging - spdif
    11 Bal imaging - spdif.PNG

    12 Bal imaging - WDM
    12 Bal imaging - WDM.PNG

    13 Bal imaging 30R
    13 Bal imaging 30R.PNG

    14 Bal imaging 300R
    14 Bal imaging 300R.PNG

    15 Bal imaging Soft - spdif
    15 Bal imaging Soft - spdif.PNG

    16 Bal imaging Soft - WDM
    16 Bal imaging Soft - WDM.PNG

    17 Bal imaging Soft 30R
    17 Bal imaging Soft 30R.PNG

    18 Bal imaging Soft 300R
    18 Bal imaging Soft 300R.PNG


     
    Last edited: Aug 18, 2017
  16. atomicbob

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    11 crosstalk and 12 jitter

    11 crosstalk

    01 Bal crosstalk - spdif
    01 Bal crosstalk - spdif.PNG

    02 Bal crosstalk - WDM
    02 Bal crosstalk - WDM.PNG

    03 SE crosstalk - spdif
    03 SE crosstalk - spdif.PNG

    04 SE crosstalk - WDM
    04 SE crosstalk - WDM.PNG

    05 Bal crosstalk 30R
    05 Bal crosstalk 30R.PNG

    06 Bal crosstalk 300R
    06 Bal crosstalk 300R.PNG


    12 jitter

    01 Bal inferred jitter - spdif
    01 Bal inferred jitter - spdif.PNG

    02 Bal inferred jitter - WDM
    02 Bal inferred jitter - WDM.PNG

    03 SE inferred jitter - spdif
    03 SE inferred jitter - spdif.PNG

    04 SE inferred jitter - WDM
    04 SE inferred jitter - WDM.PNG





     
    Last edited: Aug 18, 2017
  17. atomicbob

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    13a square wave response

    01 Bal 20 Hz sqr 0 dBFS 12 Vpp 10mS div - spdif
    01 Bal 20 Hz sqr 0 dBFS 12 Vpp 10mS div - spdif.PNG

    02 Bal 20 Hz sqr 0 dBFS 12 Vpp 100uS div - spdif
    02 Bal 20 Hz sqr 0 dBFS 12 Vpp 100uS div - spdif.PNG

    03 Bal 20 Hz sqr -3 dBFS 8 Vpp 10mS div - spdif
    03 Bal 20 Hz sqr -3 dBFS 8 Vpp 10mS div - spdif.PNG

    04 Bal 20 Hz sqr -3 dBFS 8 Vpp 100uS div - spdif
    *corrected measurement*
    20170814-23 dac1541 Bal 20 Hz sqr -3 dBFS 8 Vpp 100uS div - spdif.PNG



    05 SE 20 Hz sqr 0 dBFS 6 Vpp 10mS div Lin - spdif
    05 SE 20 Hz sqr 0 dBFS 6 Vpp 10mS div Lin - spdif.PNG

    06 SE 20 Hz sqr 0 dBFS 6 Vpp 500uS div Lin - spdif
    06 SE 20 Hz sqr 0 dBFS 6 Vpp 500uS div Lin - spdif.PNG

    07 SE 20 Hz sqr 0 dBFS 6 Vpp 100uS div Lin - spdif
    07 SE 20 Hz sqr 0 dBFS 6 Vpp 100uS div Lin - spdif.PNG

    08 SE 20 Hz sqr -4 dBFS 4 Vpp 10mS div Lin - spdif
    08 SE 20 Hz sqr -4 dBFS 4 Vpp 10mS div Lin - spdif.PNG

    09 SE 20 Hz sqr -4 dBFS 4 Vpp 500uS div Lin - spdif
    09 SE 20 Hz sqr -4 dBFS 4 Vpp 500uS div Lin - spdif.PNG

    10 SE 20 Hz sqr -4 dBFS 4 Vpp 100uS div Lin - spdif
    10 SE 20 Hz sqr -4 dBFS 4 Vpp 100uS div Lin - spdif.PNG

     
    Last edited: Aug 29, 2017
  18. atomicbob

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    13b square wave response

    11 Bal HP 20 Hz sqr A=-22 0 dBu 10mS div 30R Mix WDM
    11 Bal HP 20 Hz sqr A=-22 0 dBu 10mS div 30R Mix WDM.PNG

    12 Bal HP 20 Hz sqr A=-22 0 dBu 100uS div 30R Mix WDM
    12 Bal HP 20 Hz sqr A=-22 0 dBu 100uS div 30R Mix WDM.PNG

    13 Bal HP 20 Hz sqr A=-22 0 dBu 10mS div 300R Mix WDM
    13 Bal HP 20 Hz sqr A=-22 0 dBu 10mS div 300R Mix WDM.PNG

    14 Bal HP 20 Hz sqr A=-22 0 dBu 100uS div 300R Mix WDM
    14 Bal HP 20 Hz sqr A=-22 0 dBu 100uS div 300R Mix WDM.PNG

     
    Last edited: Aug 18, 2017
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    14 Soekris dac1541 27 bit resolution architecture - Single Ended outputs

    The following oscillographic time domain and 8192 point FFT graphs are not averages unless otherwise indicated. Watch the Y axis carefully for time domain levels as it varies with level changes.


    dac1541 SE 1 KHz -90 dBFS - ASIO:
    20170816-20 dac1541 SE 1 KHz -90 dBFS - ASIO.PNG
    dac1541 SE 1 KHz -100 dBFS - ASIO:
    20170816-21 dac1541 SE 1 KHz -100 dBFS - ASIO.PNG

    dac1541 SE 1 KHz -110 dBFS - ASIO:
    20170816-22 dac1541 SE 1 KHz -110 dBFS - ASIO.PNG
    dac1541 SE 1 KHz -120 dBFS - ASIO:
    20170816-23 dac1541 SE 1 KHz -120 dBFS - ASIO.PNG
    dac1541 SE 1 KHz -130 dBFS - ASIO:
    20170816-24 dac1541 SE 1 KHz -130 dBFS - ASIO.PNG
    The oscillographic waveform is a mess and not shown for sake of clarity, but the FFT clearly indicates the presence of the 1 KHz sinusoid at -130 dBFS. Wow!

    dac1541 SE 1 KHz -140 dBFS - ASIO:
    20170816-25 dac1541 SE 1 KHz -140 dBFS - ASIO.PNG
    It was necessary to use a rolling average of 8 FFTs but again the 1 KHz sinusoid at -140 dBFS is clearly discernible. For a Single Ended output both the signal resolution and residual noise floor are worthy of notice. Double wow!


    For comparison the following Eitr + Gungnir MB Single Ended outputs are provided.
    ASIO4ALL would not play well with Eitr driver so it was necessary to use WDM.

    Eitr + Gungnir MB SE 1 KHz -90 dBFS - WDM:
    20170816-18 Gungnir MB SE 1 KHz -90 dBFS - WDM.PNG

    Eitr + Gungnir MB SE 1 KHz -100 dBFS - WDM:
    20170816-21 Gungnir MB SE 1 KHz -100 dBFS - WDM.PNG

    Eitr + Gungnir MB SE 1 KHz -110 dBFS - WDM:
    20170816-22 Gungnir MB SE 1 KHz -110 dBFS - WDM.PNG
    Again the time domain oscillographic waveform is a mess and not shown for sake of clarity. However the 1 KHz sinusoid at -110 dBFS is definitely present.

    Eitr + Gungnir MB SE 1 KHz -120 dBFS - WDM:
    20170816-23 Gungnir MB SE 1 KHz -120 dBFS - WDM.PNG
    Noise floor reached with 1 KHz -120 dBFS sinusoidal input. It should be remembered that this represents excellent performance for a MB DAC, which we are beginning to take for granted.
     
    Last edited: Aug 29, 2017
  20. atomicbob

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    14 Soekris dac1541 27 bit resolution architecture - Balanced outputs

    The following oscillographic time domain and 8192 point FFT graphs are not averages unless otherwise indicated. Watch the Y axis carefully for time domain levels as it varies with level changes.

    dac1541 Bal 1 KHz -90 dBFS - ASIO:
    20170816-20 dac1541 Bal 1 KHz -90 dBFS - ASIO.PNG
    dac1541 Bal 1 KHz -100 dBFS - ASIO:
    20170816-21 dac1541 Bal 1 KHz -100 dBFS - ASIO.PNG
    dac1541 Bal 1 KHz -110 dBFS - ASIO:
    20170816-22 dac1541 Bal 1 KHz -110 dBFS - ASIO.PNG

    dac1541 Bal 1 KHz -120 dBFS - ASIO:
    20170816-23 dac1541 Bal 1 KHz -120 dBFS - ASIO.PNG
    dac1541 Bal 1 KHz -130 dBFS - ASIO:
    20170816-24 dac1541 Bal 1 KHz -130 dBFS - ASIO.PNG A little hard to see but the 1 KHz -130 dBFS sinusoid signal is clearly present.


    dac1541 Bal 1 KHz -140 dBFS - ASIO:
    20170816-25 dac1541 Bal 1 KHz -140 dBFS - ASIO.PNG
    Harder to see at -140 dBFS and necessary to use a rolling average of 8 FFTs but the 1 KHz sinusoid is present, though there is a bit of mains and other noise also clearly present in the FFT.

    For comparison the following Eitr + Gungnir MB Balanced outputs are provided.
    ASIO4ALL would not play well with Eitr driver so it was necessary to use WDM.

    Eitr + Gungnir MB SE 1 KHz -90 dBFS - WDM:
    20170816-18 Gungnir MB Bal 1 KHz -90 dBFS - WDM.PNG

    Eitr + Gungnir MB SE 1 KHz -100 dBFS - WDM:
    20170816-21 Gungnir MB Bal 1 KHz -100 dBFS - WDM.PNG

    Eitr + Gungnir MB SE 1 KHz -110 dBFS - WDM:
    20170816-22 Gungnir MB Bal 1 KHz -110 dBFS - WDM.PNG
    Limit of 24 bits reached. Reminder, this is excellent performance.

    Eitr + Gungnir MB SE 1 KHz -120 dBFS - WDM:
    20170816-23 Gungnir MB Bal 1 KHz -120 dBFS - WDM.PNG
    Noise floor. -120 dBFS is equivalent of 0 signal for Eitr+Gungnir MB.

    Some closing thoughts.

    General beliefs hold that balanced outputs may provide slightly higher performance over single ended. This would appear to be true for Gungnir MB in this specific measurement attribute. However it also appears that the reverse is true for the dac1541. SE outputs have lower noise and slightly better resolution than balanced. Balance is useful when cable distances are long between audio equipment or a specific need for high Common Mode Rejection is required. Otherwise Single Ended is perfectly suitable, requires less components in the signal path and is typically easier / less costly to implement.

    dac1541 and Gungnir MB are both very capable DACs. While resolution measurements provide insights for a specific attribute, it should not be the sole input for decision of which DAC is more suitable for a particular user. Personal preferences, other audio equipment employed, additional measurement attributes (graphs, not just numbers) and preferably personal audition should be considered.

    My lab will be adding a dac1421 as I don't need the balanced feature. But if I did need the balanced features the slight amount of noise depicted in a few balanced output graphs in this series of posts would not cause me any concern.

    Lest anyone wonder, I will not be parting with my Gungnir MB. One of the benefits of running an acoustic lab is having a library of devices, DACs included.





     
    Last edited: Aug 29, 2017

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