Morpheus technical measurements

Discussion in 'Source Measurements' started by atomicbob, Aug 2, 2020.

  1. atomicbob

    atomicbob dScope Yoda

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    Morpheus 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 spdif 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
    9. Audioquest Forest and Schiit Pyst USB cables
    9. Vaunix Lab Brick USB hub
    10. Shielded 14AWG and 16AWG power cables

    Measurements are made in accordance with AES17:2015

    Why I measure multiple digital inputs on DACs.
    AES/EBU and spdif inputs are important for use in my acoustic lab. The lab is wired for Dante AOIP delivery in multiple locations. DACs are easily AB and ABX compared with synchronized identical source data streams from Dante to AES or spdif bridges. Running USB AB and ABX comparisons involves a lot more effort to maintain synchronization. I am not concerned with short AB or ABX but find it distracting to change setups during listening exercises. Flipping a switch between synchronized level matched DACs minimizes distrations allowing better auditory focus.

    Often a given DAC has been optimized for best measured results on the ASIO USB input and the other digital inputs fall a bit short. Better DAC design supports nearly the same performance on the various digital inputs.

    Morpheus
    Measurements for record commenced after warmup of 168 hours.
    Measurements for each digital input were performed over a period of several days.

    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 - spdif input - Bal XLR outputs
    Post 7 - spdif input - SE RCA outputs
    Post 8 - square wave response
    Post 9 - distortion series part A
    Post 10 - distortion series part B
    Post 11 - reserved for additional data and corrections


    Notable highlights:
    Dynamic Range between 125 and 128 dB on all outputs
    Residual noise < -127 dBFS on Bal outputs
    Residual noise < -123 dBFS on SE outputs
    Balance output cross-talk is dual mono with > 140 dB isolation

    Notable anomalies:
    Morpheus ASIO USB driver frequently crashed dScope measurement application requiring manual measurements with mitigations including ASIO4ALL and Morpheus driver via WASAPI. JRiver also had issues with the ASIO driver. WASAPI again proved more successful.

    Distortion vs amplitude exhibits a large spectral change when transitioning between -54.5 dBFS and - 55 dBFS. See the distortion series part A & B.

    Listening notes:
    Adjusting Morpheus to -1 dBFS produced balanced output match of -0.077 dB with respect to KTE Spring2
    JRiver output to Dante digital delivery to AES input at 88.2 KHz used for listening evaluation.My comments are in the subtle to nuanced category of discriminant description, as opposed to either obvious (major) or noticeable (moderate). So please keep in mind when reading my comments below.
    Depending on the dynamic range of material KTE Spring2 provided greater clarity and focus over Morpheus.
    Blackground was perceived to be deeper on Spring2 with Morphues being slightly murky.
    Involvement was more engaging for Spring2 than Morpheus.
    More casual background listening reduces these subtle differences to nearly zero.

    Listening evaluation picture:
    DSC_0542_small.jpg

    Measurement setup picture example:
    DSC_0523_small.jpg
     
    Last edited: Aug 2, 2020
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  2. atomicbob

    atomicbob dScope Yoda

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    AES input Bal output measurements

    Morpheus Dynamic Range AES input Bal output
    20200717 morpheus dynamic range FFT AES Bal.png

    Excellent performance
    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.

    Morpheus -120dBFS sine AES input Bal output
    FFT_0_L1T18_1.png

    Morpheus A04 THD+N THD nth-HD FFT AES input Bal output
    20200717 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal 0dBFS - AES.png

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

    Morpheus Amplitude Linearity AES input Bal output - Left Channel
    G2_L1T3_1_A.png

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

    Morpheus Residual Noise Bal AES input Bal output - Left Channel
    FFT_2_L1T16_1_A.png

    Complete AES input Bal output analysis report pdf attached
     

    Attached Files:

    Last edited: Aug 2, 2020
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  3. atomicbob

    atomicbob dScope Yoda

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    AES input SE output measurements

    Morpheus Dynamic Range AES input SE output
    20200717 morpheus dynamic range FFT AES SE t2.png

    Morpheus A04 THD+N THD nth-HD FFT AES input SE output
    20200717 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT SE 0dBFS - AES.png

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

    Morpheus Amplitude Linearity AES input SE output - Left Channel
    G2_L1T3_1_A.png

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

    Morpheus Residual Noise AES input SE output - Left Channel
    FFT_2_L1T16_1_A.png

    Complete AES input SE output analysis report pdf attached
     

    Attached Files:

    Last edited: Aug 2, 2020
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  4. atomicbob

    atomicbob dScope Yoda

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    USB USB input Bal output measurements

    Morpheus Dynamic Range USB input Bal output
    20200717 morpheus dynamic range FFT USB Bal.png

    Morpheus -120dBFS sine USB input Bal output
    FFT_0_L1T18_1.png

    Morpheus A04 THD+N THD nth-HD FFT USB input Bal output
    20200717 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal 0dBFS - USB.png

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

    Morpheus Amplitude Linearity USB input Bal output - Left Channel
    G2_L1T3_1_A.png

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

    Morpheus Residual Noise Bal USB input Bal output - Left Channel
    FFT_2_L1T16_1_A.png

    Complete USB input Bal output analysis report pdf attached
     

    Attached Files:

    Last edited: Aug 2, 2020
  5. atomicbob

    atomicbob dScope Yoda

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    USB USB input SE output measurements

    Morpheus Dynamic Range USB input SE output
    20200717 morpheus dynamic range FFT USB SE.png

    Morpheus A04 THD+N THD nth-HD FFT USB input SE output
    20200717 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT SE 0dBFS - USB.png

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

    Morpheus Amplitude Linearity USB input SE output - Left Channel
    G2_L1T3_1_A.png

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

    Morpheus Residual Noise USB input SE output - Left Channel
    FFT_2_L1T16_1_A.png

    Complete USB input SE output analysis report pdf attached
     

    Attached Files:

    Last edited: Aug 2, 2020
  6. atomicbob

    atomicbob dScope Yoda

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    spdif input Bal output measurements

    Morpheus Dynamic Range spdif input Bal output
    20200723 morpheus dynamic range FFT spdif Bal.png

    Morpheus -120dBFS sine spdif input Bal output
    FFT_0_L1T18_1.png

    Morpheus A04 THD+N THD nth-HD FFT spdif input Bal output
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal 0dBFS - spdif - dBFS scale.png

    Morpheus 50 + 7000 Hz spdif input Bal output - Left Channel
    FFT_2_L1T13_1_A.png

    Morpheus Amplitude Linearity spdif input Bal output - Left Channel
    G2_L1T3_1_A.png

    Morpheus THD+N vs Frequency spdif input Bal output - Left Channel
    G2_L1T5_1_A.png

    Morpheus Residual Noise Bal spdif input Bal output - Left Channel
    FFT_2_L1T16_1_A.png

    Complete spdif input Bal output analysis report pdf attached
     

    Attached Files:

    Last edited: Aug 2, 2020
  7. atomicbob

    atomicbob dScope Yoda

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    spdif input SE output measurements

    Morpheus Dynamic Range spdif input SE output
    20200723 morpheus dynamic range FFT spdif SE.png

    Morpheus A04 THD+N THD nth-HD FFT spdif input SE output
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT SE 0dBFS - spdif - dBFS scale.png

    Morpheus 50 + 7000 Hz spdif input SE output - Left Channel
    FFT_2_L1T13_1_A.png

    Morpheus Amplitude Linearity spdif input SE output - Left Channel
    G2_L1T3_1_A.png

    Morpheus THD+N vs Frequency spdif input SE output - Left Channel
    G2_L1T5_1_A.png

    Morpheus Residual Noise spdif input SE output - Left Channel
    FFT_2_L1T16_1_A.png

    Complete spdif input SE output analysis report pdf attached
     

    Attached Files:

    Last edited: Aug 2, 2020
  8. atomicbob

    atomicbob dScope Yoda

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    square wave response

    Morpheus Square Wave 2000mV 1uS/div AES input Bal output - Left Channel
    Inset displays overall square wave response at 10mS/div
    20200717 SigGen morpheus 20 Hz square 2000mVpp 1uS div 5MHz filter AES Bal BW calc t2.png
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 5.266uS = 66.46 KHz


    Morpheus Square Wave 2000mV 1uS/div AES input SE output - Left Channel
    Inset displays overall square wave response at 10mS/div
    20200717 SigGen morpheus 20 Hz square 2000mVpp 1uS div 5MHz filter AES SE BW calc.png
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 5.381uS = 65.04 KHz


    Morpheus Square Wave 2000mV 1uS/div USB input Bal output - Left Channel
    Inset displays overall square wave response at 10mS/div
    20200717 SigGen morpheus 20 Hz square 2000mVpp 1uS div 5MHz filter USB Bal BW calc.png
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 5.203uS = 66.27 KHz


    Morpheus Square Wave 2000mV 1uS/div USB input SE output - Left Channel
    Inset displays overall square wave response at 10mS/div
    20200717 SigGen morpheus 20 Hz square 2000mVpp 1uS div 5MHz filter USB SE BW calc.png
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 5.344uS = 65.49 KHz
     
    Last edited: Aug 2, 2020
  9. atomicbob

    atomicbob dScope Yoda

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    distortion series part A

    Morpheus A04 THD+N THD nth-HD FFT AES input Bal output measurements 0 to -100 dBFS
    Watch how the spectrum changes with stimulus amplitude

    0 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal 0dBFS - AES.png

    -10 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -10dBFS - AES.png

    -20 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -20dBFS - AES.png

    -30 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -30dBFS - AES.png

    -40 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -40dBFS - AES.png

    -50 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -50dBFS - AES.png

    -60 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -60dBFS - AES.png

    Note how distortion spectrum (and numbers) drop at -60 dBFS

    -70 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -70dBFS - AES.png

    -80 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -80dBFS - AES.png

    -90 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -90dBFS - AES.png
     
    Last edited: Aug 2, 2020
  10. atomicbob

    atomicbob dScope Yoda

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    distortion series part B

    -100 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -100dBFS - AES.png


    The distortion spectrum transition occurs between -54 dBFS and -54.5 dBFS:

    -54 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -54dBFS - AES.png

    -54.5 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -54_5dBFS - AES.png

    -55 dBFS
    20200723 morpheus A04 THD+N THD nth-HD 4+HD+N 60Hz FFT Bal -55dBFS - AES.png

    Morpheus THD+N vs Amplitude AES input Bal output
    G2_L1T6_1.png
     
    Last edited: Aug 2, 2020
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  11. atomicbob

    atomicbob dScope Yoda

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    reserved for additional data and corrections.
     
  12. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    Thanks for powering through this one. Sounds like a huge pain in the ass with their ASIO driver.
     
  13. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Very interesting. The lower level signal results look good, but anything above that ~55dB-ish point looks somewhat "dirty", if nothing else due to the skirting around the signal and harmonics.

    Also interesting that it seems coupled with a slight rise on the linearity plot.

    Makes me wonder what this might mean for music and/or if any of things contributes to the somewhat relaxed, slightly grey and hazy sort of sound.

    Wonder what causes this, but that might start dipping too much into intellectual property on the technical front.
     
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  14. purr1n

    purr1n Finding his inner redneck

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    Remember this?
    [​IMG]
    https://www.superbestaudiofriends.o...heus-dac-measurements.9275/page-2#post-299933

    So glad @atomicbob confirmed my results. I thought I could have been doing something wrong.

    Nonsense. IP means we just can't use it and sell it if it's patented. I don't think there is a law that says we cannot take measurements and infer implementation.
     
    Last edited: Aug 3, 2020
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  15. purr1n

    purr1n Finding his inner redneck

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    @atomicbob: Can you run an FFT for a single sine at an even multiple of the sampling rate at or near 0dbFS, say 1000Hz, and then run 1001Hz?
     
  16. atomicbob

    atomicbob dScope Yoda

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    The Morpheus is with @Hands now.
     
  17. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Oh, sorry, all I meant is that while we can guess and infer all we want on what technical and design elements cause this (and may get close to the answer), I'm sure asking Cees about it would not get us much insight. Either that or were someone bored enough to reverse engineer the thing to try to figure it out, that wouldn't go over so well if that info got dumped publicly.

    I'm guessing it's probably related to the ways Cees previously mentioned splitting up and recombining 24-bit signals and/or the incorporation of the pre-amp. I never shared my Adagio measurements publicly due to uncertainty on their accuracy, but I saw some pretty funky and variable results depending on how you used the pre-amp and at what levels.
     
  18. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    @purr1n Thanks for linking to your previous measurements. I forgot that you too had issues with "grass" and "dirty" results in certain test cases. Since that seemed due to a mismatch with signal frequencies, ADC sampling rate, blah blah, may or may not be an issue outside of that sort of test environment.

    I'll try what you suggested and see if I can replicate. Let me know if you think of other things to check.
     
  19. atomicbob

    atomicbob dScope Yoda

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    Avermetrics:
    2020-5-8_17-13-39_Avermetrics_THD+N_vs_amplitude.png

    dScope:
    G2_L1T6_1_dScope_AES_Bal_THD+N_vs_amplitude.png

    Overlay:
    dScope_Avermetrics_THD+N_vs_amplitude_overlay.png
    Very high correlation.

    Imagine that. Two independent measurements using two different analyzers on the same component and achieving nearly identical results. Keep that in mind when viewing measurement data from the various sites around the internet.
     
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  20. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Like the Adagio and Jade, the technical specifications for the Morpheus say that the pre-amp functionality comes from changing the voltage reference to the DAC modules themselves and is not handled in the digital domain.

    I'm not going to argue which approach makes more sense, but I can say that my (unpublished) Adagio measurements showed some amount of variability to distortion, both in amount and characteristic, depending on how you set its volume.

    So, I wanted to check for similar behavior on the Morpheus. I found a couple interesting elements:

    1. 0db through -54dB signals always exhibit what I'll call "static" harmonic content that changes very little, to not at all, regardless of the DACs attenuation level.

    For example, with a 1KHz signal at any level between 0dB and -54dB, you'll see what look like harmonic spikes at about every interval. Let's say the 2nd harmonic on a 1KHz, -1dB signal sits at around -100dB.

    Change the volume and watch your FFT in real time. You'll notice the 2KHz harmonic never really changes. It always sits right around -100dB, and I do not mean relative to the fundamental.

    There are many other harmonics that exhibit this behavior, but not all. Some do change depending on your attenuation setting.

    Between the 0dB and -20dB attenuation settings, you'll see all sorts of changes to some harmonics. At -20dB and lower, you should see harmonics across the board essentially don't change in an absolute sense. At that point, only the fundamental will continue to change (i.e. drop).


    2. The 3rd and 5th harmonics, and a couple of others to a minor extent, change relative to the fundamental based on the attenuation setting.

    Here's an example. With a 1KHz, -1dB sine, I checked the 3rd and 5th harmonics and graphed their relative different to the fundamental from 0dB to -13dB on the DACs attenuation scale.


    Sonnet Morpheus PreAmp vs Distortion.png


    Again, this is only in the context of a 1KHz sine at -1dB. With a 1K, -54dB signal, odd harmonics were dominant. Lowering the volume on the DAC didn't so much to change those as it did just "raise" all the other harmonics (really, the whole floor). And that's not to say all frequency or signal types will respond this way, so don't go assuming you can just slap your Morpheus on -8dB and call it good.

    Even if you figured you'd maximize performance of a hot 1KHz signal, you should note that the 0dB or -1dB DAC volume settings seem closest to a 2V RMS SE output (single ended). Going lower means you won't be at that standard, which may or may not be fine for each individual's use case.


    3. Playing a sine between -54dB and 0dB and then adjusting the DAC's attenuation value to something that outputs the signal below -55dB does NOT change the harmonic characteristics in the same way playing a -55dB or lower signal does, as seen in other measurements.


    Some of this behavior I'd almost guarantee ties back directly to the nature of adjusting the DAC reference voltage to impact output levels. The rest I would imagine boils down to the digital processing techniques, likely the way the digital signal bits are "split in half" and recombined in the analog realm.

    I will have to check my Pavane, an old school Level 1 (aka original) model, to see if it exhibits same 55dB-ish transitional distortion change trait.
     
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