NITSCH x Schiit Magni Piety Technical Measurements

Discussion in 'Headphone Amplifier Measurements' started by atomicbob, Oct 3, 2022.

  1. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    NITSCH x Schiit Magni Piety 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, Keysight 34465A, Cal Test CT2593-2 balanced probe
    2. Balanced XLR cables Belden 1800F with Neutrik 110R AES connectors (if used)
    3. Single Ended cables Audioblast HQ-1 3 ft with Rean RCA connectors
    4. 32 and 300 ohm loads used for measurements
    5. dScope analyzer sample rate 48 KHz unless otherwise noted
    6. 0dBu level used for testing unless otherwise noted
    7. Amplifier input to output gain set for 0 dB unless otherwise noted
    8. Audioquest Forest and Schiit Pyst USB cables used with measurement equipment
    9. Vaunix Lab Brick USB hub
    10. Shielded 14AWG and 16AWG power cables
    11. ESD, EMI/RFI controlled lab bench and workspace

    Measurements are made in accordance with AES17:2015

    Sensitivity data for two headphones to keep in mind while viewing these measurements:
    HD 650 impedance 300R, sensitivity 98 dB/mW
    HE-500 impedance 38R, sensitivity 89 dB/mW

    SPL levels for above headphones for reference:
    0 dBu 300R 2.00 mW - 101 dBSPL @ 98dB/mW
    0 dBu 30R 20.00 mW - 102 dBSPL @ 89dB/mW

    All testing performed at 0 dBu unless otherwise noted.
    This level is consistent with listening to headphones (referenced above) at 90 dBSPL average with peaks to 100 dBSPL, if the music has 10 dB Peak to Avg ratio. That is LOUD for long listening sessions.

    Magni Piety
    Measurements commenced after 1 hour of warmup.
    Measurements were performed over a period of several days.

    Index
    Post 1 – Measurement setup description, highlights
    Post 2 – 300 ohm load, High gain setting
    Post 3 – 300 ohm load, Low gain setting
    Post 4 – 32 ohm load, High gain setting
    Post 5 – 32 ohm load, Low gain setting
    Post 6 – miscellaneous observations
    Post 7 – reserved for corrections and / or additional data

    Measurement setup picture:
    01 DSC_0934_small.jpg
    Standard setup with schiit load for 300R and 32R loads

    Listening evaluation picture:
    02 DSC_0941_small.jpg
    Magni Piety inputs switched between Yggdrasil LIM and Holo Spring 2 KTE SE outputs.
    ECP DSHA3-F switched balanced inputs between Yggdrasil LIM and Holo Spring 2 KTE balanced outputs.
    This provided considerable flexibility during listening sessions. There are plenty of impressions threads on the forum where more detailed and nuanced thoughts about the various components are discussed. For my preferences, either I like how it renders music or I don’t. Piety often felt as if it was a skillful combination of the powerful bass reminiscent of EC 300B, magic mid-range of SW51+ and high end transient response usually associated with Cavalli amps. I will be acquiring several for my lab.

    Notable highlights:
    Due to some interesting attributes of this amp I will provide additional commentary and interpretation from which I would normally refrain.

    Let's get this out of the way first.
    Generator level set to 0 dBu, Amp set for 0 dB gain with 300R load, High gain selected:

    THD+N: 0.00168% Left channel (SINAD 95.5 dB)
    THD+N: 0.00169% Right channel (SINAD 95.4 dB)


    These are respectable levels but do not rival the lowest achieved by very high Negative FeedBack (NFB) designs. Those who worship THD+N / SINAD should stop at this point and dismiss this amp. The remainder will be a waste of time. However if you consider there is more to an amp than SINAD / THD+N please continue. This special sounding amp offers another opportunity to demonstrate how chasing low distortion numbers out of context is the very definition of foolishness.

    03 20220927 Magni Piety A04 distortion 0dBu 300R Hi gain - annotated.png
    The greatest components contributing to Piety’s THD+N are AC mains noise. However these residual noise components are considerably below the threshold of perception for many common headphones. For Sennheiser and other headphones with similar sensitivities that threshold is -75 dBu.

    04 20220927 Magni Piety A00 Dist 60+120Hz vs frequency 300R Hi gain - annotated.png
    Trace ID:
    Yel: THD+N
    Blu: 60 Hz AC mains noise
    Red: 120 Hz AC mains noise
    Grn: THD (Total Harmonic Distortion excluding noise)
    Below approximately +6 dBu 60 Hz mains noise dominates the THD+N measurement. Above +6 dBu THD becomes the dominant contributor to THD+N.

    05 magni piety AC mains noise vs headphone sensitivities.png
    From the chart above note that most headphones won’t produce sufficient SPL to allow audible detection of Piety AC mains noise. Only the insanely sensitive Shure SE215 and Westone UM2 (and IEMs with similar sensitivities) might approach threshold of perception in very quiet ambient conditions.

    06 20220927 Magni Piety A00 Dist 2 3 4+ vs frequency 300R Hi gain +20 dBu annotated.png
    Trace ID:
    Yel: THD+N
    Grn: 2nd harmonic distortion (D2)
    Blu: 3rd harmonic distortion (D3)
    Red: 4+HD+N (crap factor including noise)
    As previously shown AC mains noise dominates THD+N measurement below approximately +6 dBu. Above +9 dBu D2 dominates THD+N until approximately +17 dBu where D3 becomes dominant.

    Between this sweep measurement and the previous one above it may be observed how THD+N obscures a clear picture of the distortion profile for a given component. Think of THD+N as a lossy data compression technique. The danger with such data reduction is some distortions are of more concern than others. Distortion at some frequencies are more audible than others thanks to the non-linear behavior of the Human Auditory System as demonstrated with ISO Contours of Equal Loudness (Fletcher-Munson curves.)

    magni piety gain linearity 300R Hi Gain L ch
    07 magni piety gain linearity 300R Hi Gain L ch.png
    Consider what happens when a pair of headphones produces 100 dB SPL at 0 dBu output from Piety. This implies 0 dB SPL when Piety output is -100 dBu. Over that range Piety has excellent gain linearity.

    magni piety 20 Hz square wave response 2Vpp 1uS div no filter 300R Hi gain
    08 20220928 SG magni piety 20 Hz sqr 2Vpp 1uS div no filter 300R Hi gain BW calc annotated.png
    Piety has a DC coupled output which is demonstrated by the perfect square wave response shown in the overview inset. The vertical line in the inset denotes what part of the overview has been zoomed for the main display. Zoom factor of 10,000 is necessary to observe 1.243 uS rise time 10% to 90% response when presented a fast step input from the signal generator. Using the following formula

    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 1.243 uS = 281.6 KHz

    This implies Magni Piety has a bandwidth from DC to > 280 KHz. PFA!

    magni piety 20 Hz sine 30Vpp 20mS div 1MHz filter 300R Lo gain
    09 20220928 SG magni piety 20 Hz sine 30Vpp 20mS div 1MHz filter 300R Lo gain - soft clip 1.png
    With a 300R load and gain set to Low, Magni Piety can produce over 30 Vpp!!
    Trace ID:
    Blu: input to Piety
    Red: output from Piety
    As output approaches maximum capability observe how the signal begins to soft clip like a tube amplifier.

    magni piety 20 Hz sine 30Vpp 20mS div 1MHz filter 300R Lo gain
    10 20220928 SG magni piety 20 Hz sine 30Vpp 20mS div 1MHz filter 300R Lo gain - soft clip 2.png
    Increasing input level further the output is clearly soft clipping, just like a tube amp. Pretty amazing for a solid state amplifier without transformers.

    Magni Piety Output Impedance
    Hi Gain: 0.64 ohms
    Lo Gain: 0.53 ohms

    Threshold of AC Mains noise perception
    In my acoustic lab when listening between 65 and 75 dB SPL on headphones with sensitivity of 95 to 100 dB/mw, mains noise of -75 dBu is at the threshold of perception. At this level I perceive the blackground compromised and a certain sourness to the listening experience that would mostly disappear when listening level was increased to 75 to 85 dB SPL. Mains hum between tracks is still evident. In normal home environments ambient noise masking is likely sufficient to hide this issue if AC mains noise is at or below -75 dBu. If AC mains noise is at or below -85 dBu then I no longer perceive it with the headphones of the sensitivity mentioned in my very quiet acoustic lab. Most listeners will be undisturbed by this issue to which I am so sensitive.
    Magni Piety AC mains noise is below -98 dBu and will not be a problem except possibly with insanely sensitive IEMs such as Shure SE215 or Westone UM2.
     
    • Epic Epic x 35
    • Like Like x 6
    • Agreed, ditto, +1 Agreed, ditto, +1 x 1
    • List
    Last edited: Oct 3, 2022
  2. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    300 ohm load, High gain setting

    Magni Piety A04 THD+N THD nth-HD FFT 300 ohm load, High gain
    01 20220927 Magni Piety A04 THD+N  THD  nth-HD FFT 300R - 4+HD+N with 60Hz 0dBu.png

    Magni Piety 50 + 7000 Hz 300 ohm load, High gain - Left Channel
    02 FFT_2_L1T13_1_A Piety 300R Hi gain 50+7K.png

    Magni Piety Gain Linearity 300 ohm load, High gain - Left Channel
    03 G2_L1T3_1_A Piety 300R Hi gain linearity.png

    Magni Piety THD+N vs Frequency 300 ohm load, High gain - Left Channel
    04 G2_L1T5_1_A Piety 300R Hi gain THD+N vs Freq.png

    Magni Piety Residual Noise 300 ohm load, High gain - Left Channel
    05 FFT_2_L1T16_1_A Piety 300R Hi gain residual noise.png

    Magni Piety Square Wave 2Vpp 1uS/div 300 ohm load, High gain - Left Channel
    06 20220928 SigGen magni piety 20 Hz square 2Vpp 1uS div no filter 300R Hi gain - BW calc.png
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 1.243 uS = 281.6 KHz

    Magni Piety Maximum Output 300 ohm load, High gain – Left Channel
    07 20220928 SigGen magni piety 20 Hz sine 30Vpp 20mS div 1MHz filter 300R Hi gain - clip calc.png

    Magni Piety THD+N 2nd 3rd 4+HD+N vs frequency 300R Hi gain
    08 20220927 Magni Piety A00 THD+N 2nd 3rd 4+HD+N vs frequency 300R Hi gain.png

    Magni Piety THD+N THD 60+120Hz vs frequency 300R Hi gain
    09 20220927 Magni Piety A00 THD+N THD 60+120Hz vs frequency 300R Hi gain.png

    Complete 300 ohm load, High gain measurement report pdf attached
     

    Attached Files:

    • Epic Epic x 6
    • Like Like x 2
    • List
    Last edited: Oct 3, 2022
  3. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    300 ohm load, Low gain setting

    Magni Piety A04 THD+N THD nth-HD FFT 300 ohm load, Low gain
    01 20220927 Magni Piety A04 THD+N  THD  nth-HD FFT 300R - 4+HD+N with 60Hz 0dBu.png

    Magni Piety 50 + 7000 Hz 300 ohm load, Low gain - Left Channel
    02 FFT_2_L1T13_1_A Piety 300R Lo gain 50+7K.png

    Magni Piety Gain Linearity 300 ohm load, Low gain - Left Channel
    03 G2_L1T3_1_A Piety 300R Lo gain linearity.png

    Magni Piety THD+N vs Frequency 300 ohm load, Low gain - Left Channel
    04 G2_L1T5_1_A Piety 300R Lo gain THD+N vs Freq.png

    Magni Piety Residual Noise 300 ohm load, Low gain - Left Channel
    05 FFT_2_L1T16_1_A Piety 300R Lo gain residual noise.png

    Magni Piety Square Wave 2Vpp 1uS/div 300 ohm load, Low gain - Left Channel
    06 20220928 SigGen magni piety 20 Hz square 2Vpp 1uS div no filter 300R Lo gain - BW calc.png
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 1.001 uS = 349.7 KHz

    Magni Piety Maximum Output 300 ohm load, Low gain – Left Channel
    07 20220928 SigGen magni piety 20 Hz sine 30Vpp 20mS div 1MHz filter 300R Lo gain - clip calc.png

    Magni Piety THD+N 2nd 3rd 4+HD+N vs frequency 300R Lo gain
    08 20220927 Magni Piety A00 THD+N 2nd 3rd 4+HD+N vs frequency 300R Lo gain.png

    Magni Piety THD+N THD 60+120Hz vs frequency 300R Lo gain
    09 20220927 Magni Piety A00 THD+N THD 60+120Hz vs frequency 300R Lo gain.png

    Complete 300 ohm load, Low gain measurement report pdf attached
     

    Attached Files:

    • Epic Epic x 6
    • Like Like x 1
    • List
    Last edited: Oct 3, 2022
  4. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    32 ohm load, High gain setting

    Magni Piety A04 THD+N THD nth-HD FFT 32 ohm load, High gain
    01 20220927 Magni Piety A04 THD+N  THD  nth-HD FFT 32R - 4+HD+N with 60Hz 0dBu.png

    Magni Piety 50 + 7000 Hz 32 ohm load, High gain - Left Channel
    02 FFT_2_L1T13_1_A Piety 32R Hi gain 50+7K.png

    Magni Piety Gain Linearity 32 ohm load, High gain - Left Channel
    03 G2_L1T3_1_A Piety 32R Hi gain linearity.png

    Magni Piety THD+N vs Frequency 32 ohm load, High gain - Left Channel
    04 G2_L1T5_1_A Piety 32R Hi gain THD+N vs Freq.png

    Magni Piety Residual Noise 32 ohm load, High gain - Left Channel
    05 FFT_2_L1T16_1_A Piety 32R Hi gain residual noise.png

    Magni Piety Square Wave 2Vpp 1uS/div 32 ohm load, High gain - Left Channel
    06 20220928 SigGen magni piety 20 Hz square 2Vpp 1uS div no filter 32R Hi gain - BW calc.png
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 1. 282 uS = 273.0 KHz

    Magni Piety Maximum Output 32 ohm load, High gain – Left Channel
    07 20220928 SigGen magni piety 20 Hz sine 17Vpp 20mS div 1MHz filter 32R Hi gain - clip calc.png

    Magni Piety THD+N 2nd 3rd 4+HD+N vs frequency 32R Hi gain
    08 20220927 Magni Piety A00 THD+N 2nd 3rd 4+HD+N vs frequency 32R Hi gain.png

    Magni Piety THD+N THD 60+120Hz vs frequency 32R Hi gain
    09 20220927 Magni Piety A00 THD+N THD 60+120Hz vs frequency 32R Hi gain.png

    Complete 32 ohm load, High gain measurement report pdf attached
     

    Attached Files:

    • Epic Epic x 4
    • Like Like x 1
    • List
    Last edited: Oct 3, 2022
  5. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    32 ohm load, Low gain setting

    Magni Piety A04 THD+N THD nth-HD FFT 32 ohm load, Low gain
    01 20220927 Magni Piety A04 THD+N  THD  nth-HD FFT 32R - 4+HD+N with 60Hz 0dBu.png

    Magni Piety 50 + 7000 Hz 32 ohm load, Low gain - Left Channel
    02 FFT_2_L1T13_1_A Piety 32R Lo gain 50+7K.png

    Magni Piety Gain Linearity 32 ohm load, Low gain - Left Channel
    03 G2_L1T3_1_A Piety 32R Lo gain linearity.png

    Magni Piety THD+N vs Frequency 32 ohm load, Low gain - Left Channel
    04 G2_L1T5_1_A Piety 32R Lo gain THD+N vs Freq.png

    Magni Piety Residual Noise 32 ohm load, Low gain - Left Channel
    05 FFT_2_L1T16_1_A Piety 32R Lo gain residual noise.png

    Magni Piety Square Wave 2Vpp 1uS/div 32 ohm load, Low gain - Left Channel
    06 20220928 SigGen magni piety 20 Hz square 2Vpp 1uS div no filter 32R Lo gain - BW calc.png
    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 1.007 uS = 347.6 KHz

    Magni Piety Maximum Output 32 ohm load, Low gain – Left Channel
    07 20220928 SigGen magni piety 20 Hz sine 17Vpp 20mS div 1MHz filter 32R Lo gain - clip calc.png

    Magni Piety THD+N 2nd 3rd 4+HD+N vs frequency 32R Lo gain
    08 20220927 Magni Piety A00 THD+N 2nd 3rd 4+HD+N vs frequency 32R Lo gain.png

    Magni Piety THD+N THD 60+120Hz vs frequency 32R Lo gain
    09 20220927 Magni Piety A00 THD+N THD 60+120Hz vs frequency 32R Lo gain.png

    Complete 32 ohm load, Low gain measurement report pdf attached
     

    Attached Files:

    Last edited: Oct 4, 2022
  6. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    Miscellaneous Observations

    How much power do you need?

    Here is a chart of some common headphones and the dB SPL they will produce at 1KHz 0 dBu:
    01 20220927 magni piety 0 dBu vs headphone sensitivities.png
    The chart above provides insight into a number of common headphones behavior when operated with 1 KHz signal at 0 dBu. Many produce between 100 and 115 dB SPL which is very loud. This reason alone justifies testing components at a more sensible 0 dBu output level than at 4V rms which is +14.3 dBu, an additional 14 dB SPL louder. Measurements for my personal use usually include testing at -20 dBu, approximately 80 dB SPL, for the Sennheiser headphones I favor. None of the power levels required begin to approach maximum output magni piety can deliver.
     
    • Epic Epic x 3
    • Like Like x 2
    • List
    Last edited: Oct 3, 2022
  7. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    reserved 7/7
    reserved for additional data and / or corrections.
     
  8. Paul Scandal

    Paul Scandal Rando

    Joined:
    Sep 2, 2021
    Likes Received:
    5
    Trophy Points:
    3
    Location:
    Florida
    Shouldn't the color be white?
     
  9. Beefy

    Beefy Almost "Made"

    Joined:
    Apr 10, 2021
    Likes Received:
    1,320
    Trophy Points:
    93
    Location:
    Canada
    The board is white, see this post on Head-Fi.
     
    • Agreed, ditto, +1 Agreed, ditto, +1 x 1
    • List
  10. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    The PCB inside is white. Lower clam shell is light grey while upper clam shell is dark gray on the unit I received.
     
  11. zerodeefex

    zerodeefex SBAF's Imelda Marcos

    Staff Member Friend BWC
    Joined:
    Sep 25, 2015
    Likes Received:
    13,131
    Trophy Points:
    113
    Might need a few to put around the house. 100% upgrading my daughter's rig with one as well.
     
  12. CEE TEE

    CEE TEE MOT: NITSCH

    Friend IEMW
    Joined:
    Sep 25, 2015
    Likes Received:
    2,910
    Trophy Points:
    93
    Location:
    California Bay Area (San Francisco)
    Home Page:
    These are the final colors, atomicbob has prototype metal from powder coat color testing (with NITSCH sticker):
    MAGNI_PROTO_11.jpg PietyFirstArticle.jpg \
    The top is semi-gloss or satin very dark grey. Black silkscreened NITSCH logo.
    The bottom is a subtle nickel/brass color with a rough sandpapery finish.
    His board is a first article from the board house just like in the photo!
     
    • Like Like x 21
    • Epic Epic x 3
    • List
    Last edited: Oct 4, 2022
  13. M3NTAL

    M3NTAL Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    1,136
    Trophy Points:
    93
    Location:
    Arizona
    What is the noise floor like with sensitive stuff? Curious how it will do with some of my IEM's.
     
  14. Paul Scandal

    Paul Scandal Rando

    Joined:
    Sep 2, 2021
    Likes Received:
    5
    Trophy Points:
    3
    Location:
    Florida
    My Vali 2++ and her Roll of Tubes look forward to your competition for the honored spot on the Mezzanine of the Folkvangr!
     
  15. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    From post 1:
    https://www.superbestaudiofriends.o...s-noise-vs-headphone-sensitivities-png.33399/
    From the chart above note that most headphones won’t produce sufficient SPL to allow audible detection of Piety AC mains noise. Only the insanely sensitive Shure SE215 and Westone UM2 (and IEMs with similar sensitivities) might approach threshold of perception in very quiet ambient conditions.

    If your IEMs are as sensitive as Shure SE215 and Westone UM2 then you might be able to detect a faint hint of AC mains noise.

    I own Westone UM2 and using those listened to Magni Piety residual noise. In Lo gain there is no noise. With Hi gain selected I could detect the faintest bit of hiss when I held my breath in my very quiet acoustic lab. The moment I resumed normal breathing my own breath noise masked the faint hiss.
     
    • Like Like x 11
    • Epic Epic x 2
    • List
  16. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    16,785
    Trophy Points:
    113
    Location:
    On planet
    Magni Piety Multitone 300R Hi gain 0 dBu total level
    20221004 Magni Piety Multitone 300R Hi gain 0 dBu total level v2.png

    It doesn't get much cleaner than that. Only a slight hint of AC mains noise between the tones. Other than that there is nothing but residual noise grass below -125 dBu. Impressive.
     
    • Like Like x 10
    • Epic Epic x 2
    • List
  17. Grattle

    Grattle Friend

    Friend
    Joined:
    Feb 17, 2017
    Likes Received:
    507
    Trophy Points:
    93
    Location:
    USA
    Love the white PCB. I've always hated red ones. First world problem indeed!
     
  18. Baten

    Baten Friend

    Friend
    Joined:
    Mar 18, 2018
    Likes Received:
    1,041
    Trophy Points:
    93
    Location:
    EU
    Really a thing of beauty.
     
    • Agreed, ditto, +1 Agreed, ditto, +1 x 1
    • List

Share This Page