Monoprice Cavalli Liquid Spark technical measurements

Discussion in 'Headphone Amplifier Measurements' started by atomicbob, Oct 6, 2018.

  1. atomicbob

    atomicbob dScope Yoda

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    Monoprice Cavalli Liquid Spark technical measurements

    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.

    The data presented were collected as follows:

    1. PrismSound dScope III, picoscope 5243B, Keysight 34461A DMM
    2. 300 and 30 ohm loads used for measurements
    3. Unbalanced cables Worlds Best Cable Gotham GAC-2 RCA
    4. Vaunix Lab Brick USB hub for measurement equipment
    5. Audioquest Forest and Schiit Pyst USB cables used for measurement equipment
    6. Amplifier gain adjusted to 0 dB gain @ 0.775 Vrms 0 dBu
    7. Spark gain switch set to high position
    8. Spark gain knob at approximately 1:00 to achieve 0 dB gain
    9. 36V SMPS for power except where noted
    10. 14 and 16 AWG sheilded power cables used

    Reference levels :
    +9 dBu 300R 16.00 mW - 110 dBSPL @ 98dB/mW
    0 dBu 300R 2.00 mW - 101 dBSPL @ 98dB/mW
    -10 dBu 300R 0.20 mW - 91 dBSPL @ 98dB/mW
    -20 dBu 300R 0.02 mW - 81 dBSPL @ 98dB/mW

    +9 dBu 30R 160.00 mW - 110 dBSPL @ 89dB/mW
    0 dBu 30R 20.00 mW - 102 dBSPL @ 89dB/mW
    -10 dBu 30R 2.00 mW - 92 dBSPL @ 89dB/mW
    -20 dBu 30R 0.20 mW - 82 dBSPL @ 89dB/mW

    Reference data on two headphones:
    HD 650 impedance 300R, sensitivity 98 dB/mW
    HE-500 impedance 38R, sensitivity 89 dB/mW

    Highlights
    Square wave response is very near that of the Liquid Crimson.
    Bandwidth is extraordinary for an amp at this price: DC to > 1.5 MHz
    Well done Dr. Cavalli!

    @Hands has posted a review here
    Schiit Magni 3 measurements, for comparison, found here

    My personal preferences include listening typically at an average of 75 dB SPL. Assuming a typical Peak to Average ratio of 10 dB puts peaks at 85 dB SPL. This suggests the measurements at -20 dBu represent my experience with HD6x0 and HD800 headphones. Auditory experiences for someone listening 10 dB SPL average higher may diverge from my own experiences.

    editorial - I believe there is a tendency to focus excessively on numbers such as THD attempting to reduce a complex topic to a single number representing a sort of goodness rating. Graphs can present far more data conveying a better understanding of the measurement over a range of frequency, levels, etc. Please don't read too much into the numbers presented. Read the tutorial presented here for a good example of why.

    Picture of the Audio Lab setup for Liquid Spark measurements
    20181005 spark dScope 5243b - t2 - small.jpg

    300 ohm load part 1 of 3

    Liquid Spark THD+N THD nth harmonic distortion (A04) FFT 0dBu 300R load
    20181005 spark A04 THD+N  THD  nth-HD FFT 300R 4XF.png

    Liquid Spark THD THD+N vs Freq 0dBu 300R
    20181005 spark THD THD+N vs Freq 300R 4XF.png

    Liquid Spark 1 KHz spectrum Left and Right 0dBu 300R load
    20181005 spark 1 KHz THD+N THD FFT 0dBu 300R 4XF.png

    Liquid Spark 50 Hz + 7000 Hz spectrum Left and Right 0dBu 300R load
    20181005 spark 50+7000Hz 0dBu 300R 4XF.png

    Liquid Spark 600 Hz + 1700 Hz spectrum Left and Right 0dBu 300R load
    20181005 spark 600+1700Hz 0dBu 300R 4XF.png

    Liquid Spark IMD spectrum Left and Right -16dBu 300R load
    20181005 spark 19+20KHz -16dBu 300R 4XF.png

    Liquid Spark residual noise spectrum Left and Right A=0dB 300R load
    20181005 spark residual noise A=0dB 300R 4XF.png

    Residual noise is very low for an SMPS powered headphone amp.

     
    Last edited: Oct 15, 2018
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  2. atomicbob

    atomicbob dScope Yoda

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    300 ohm load part 2 of 3

    Liquid Spark square wave 20 Hz 2 Vpp 10 mS / div 300R load 100 KHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 10mS div 100KHz filter 300R.png

    Liquid Spark square wave 20 Hz 2 Vpp 10 mS / div 300R load 10 MHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 10mS div 5MHz filter 300R.png

    Liquid Spark square wave 20 Hz 2 Vpp 10 uS / div 300R load 100 KHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 10uS div 100KHz filter 300R.png

    Liquid Spark square wave 20 Hz 2 Vpp 10 uS / div 300R load 10 MHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 10uS div 5MHz filter 300R.png

    Liquid Spark square wave 20 Hz 2 Vpp 1 uS / div 300R load 10 MHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 1uS div 10MHz filter 300R -BW calc.png

    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 0.186 mS = 1.88 MHz


    Liquid Spark amplitude - phase - gain (A01) 300R load
    20181005 spark A01 amplitude - phase - gain 300R.png

    Liquid Spark signal to noise (A07) 300R load
    20181005 spark A07 SNR 300R.png

    Liquid Spark THD+N THD nth harmonic distortion (A04) 300R load
    20181005 spark A04 THD+N  THD  nth-HD 300R.png

    Liquid Spark Crosstalk (A08 A09) 300R load
    20181005 spark A08 A09 Crosstalk 300R.png

     
    Last edited: Oct 6, 2018
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  3. atomicbob

    atomicbob dScope Yoda

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    300 ohm load part 3 of 3

    Liquid Spark Frequency Response and Interchannel Phase pg 1/2 300R load
    G2_L1T2_1_A.png

    Liquid Spark Frequency Response and Interchannel Phase pg 2/2 300R load
    G2_L1T2_1_B.png

    Liquid Spark Gain vs Amplitude Left 300R load
    G2_L1T3_1_A.png

    Liquid Spark Gain vs Amplitude Right 300R load
    G2_L1T3_1_B.png

    Liquid Spark THD+N vs Frequency Left 300R load

    G2_L1T5_1_A.png

    Liquid Spark THD+N vs Frequency Right 300R load

    G2_L1T5_1_B.png

    Liquid Spark THD+N vs Amplitude Left 300R load

    G2_L1T6_1_A.png

    Liquid Spark THD+N vs Amplitude Right 300R load

    G2_L1T6_1_B.png

    Liquid Spark Crosstalk Left to Right vs Frequency 300R load
    G1_L1T10_1.png

    Liquid Spark Crosstalk Right to Left vs Frequency 300R load

    G0_L1T11_1.png
     
    Last edited: Oct 6, 2018
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  4. atomicbob

    atomicbob dScope Yoda

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    30 ohm load part 1 of 3

    Liquid Spark THD+N THD nth harmonic distortion (A04) FFT 0dBu 30R load
    20181005 spark A04 THD+N  THD  nth-HD FFT 30R 4XF.png

    Liquid Spark THD THD+N vs Freq 0dBu 30R
    20181005 spark THD THD+N vs Freq 30R 4XF.png

    Liquid Spark 1 KHz spectrum Left and Right 0dBu 30R load
    20181005 spark 1 KHz THD+N THD FFT 0dBu 30R 4XF.png

    Liquid Spark 50 Hz + 7000 Hz spectrum Left and Right 0dBu 30R load
    20181005 spark 50+7000Hz 0dBu 30R 4XF.png

    Liquid Spark 600 Hz + 1700 Hz spectrum Left and Right 0dBu 30R load
    20181005 spark 600+1700Hz 0dBu 30R 4XF.png

    Liquid Spark IMD spectrum Left and Right -16dBu 30R load
    20181005 spark 19+20KHz -16dBu 30R 4XF.png

    Liquid Spark residual noise spectrum Left and Right A=0dB 30R load
    20181005 spark residual noise A=0dB 30R 4XF.png

     
    Last edited: Oct 6, 2018
  5. atomicbob

    atomicbob dScope Yoda

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    30 ohm load part 2 of 3

    Liquid Spark square wave 20 Hz 2 Vpp 10 mS / div 30R load 100 KHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 10mS div 100KHz filter 30R.png

    Liquid Spark square wave 20 Hz 2 Vpp 10 mS / div 30R load 10 MHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 10mS div 5MHz filter 30R.png

    Liquid Spark square wave 20 Hz 2 Vpp 10 uS / div 30R load 100 KHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 10uS div 100KHz filter 30R.png

    Liquid Spark square wave 20 Hz 2 Vpp 10 uS / div 30R load 10 MHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 10uS div 5MHz filter 30R.png

    Liquid Spark square wave 20 Hz 2 Vpp 1 uS / div 30R load 10 MHz BW
    20181005 SigGen spark 20 Hz square 2000mVpp 1uS div 20MHz filter 30R - BW calc.png

    Bandwidth estimation: BW (MHz) = 0.35 / RT (mS)
    Where RT = 10 to 90% Rise Time
    0.35 / 0.220 mS = 1.59 MHz


    Liquid Spark amplitude - phase - gain (A01) 30R load
    20181005 spark A01 amplitude - phase - gain 30R.png

    Liquid Spark signal to noise (A07) 30R load
    20181005 spark A07 SNR 30R.png

    Liquid Spark THD+N THD nth harmonic distortion (A04) 30R load
    20181005 spark A04 THD+N  THD  nth-HD 30R.png

    Liquid Spark Crosstalk (A08 A09) 30R load
    20181005 spark A08 A09 Crosstalk 30R.png

     
    Last edited: Oct 6, 2018
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  6. atomicbob

    atomicbob dScope Yoda

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    30 ohm load part 3 of 3

    Liquid Spark Frequency Response and Interchannel Phase pg 1/2 30R load
    G2_L1T2_1_A.png

    Liquid Spark Frequency Response and Interchannel Phase pg 2/2 30R load
    G2_L1T2_1_B.png

    Liquid Spark Gain vs Amplitude Left 30R load
    G2_L1T3_1_A.png

    Liquid Spark Gain vs Amplitude Right 30R load
    G2_L1T3_1_B.png

    Liquid Spark THD+N vs Frequency Left 30R load
    G2_L1T5_1_A.png

    Liquid Spark THD+N vs Frequency Right 30R load
    G2_L1T5_1_B.png

    Liquid Spark THD+N vs Amplitude Left 30R load
    G2_L1T6_1_A.png

    Liquid Spark THD+N vs Amplitude Right 30R load
    G2_L1T6_1_B.png

    Liquid Spark Crosstalk Left to Right vs Frequency 30R load
    G1_L1T10_1.png

    Liquid Spark Crosstalk Right to Left vs Frequency 30R load

    G0_L1T11_1.png
     
    Last edited: Oct 6, 2018
  7. atomicbob

    atomicbob dScope Yoda

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    300 ohm load power supply comparison

    Liquid Spark residual noise spectrum Left and Right A=0dB 300R load - SMPS supplied
    20181005 spark residual noise A=0dB 300R 4XF.png

    Liquid Spark residual noise spectrum Left and Right A=0dB 300R load - SMPS + Noise Nuke
    20181005 spark residual noise A=0dB 300R 4XF - noise nuke.png

    Liquid Spark residual noise spectrum Left and Right A=0dB 300R load - BK1623A LPS
    20181005 spark residual noise A=0dB 300R 4XF - BK1623A LPS.png

    Residual noise on the Liquid Spark definitely benefits from a quiet LPS. Noise Nuke moderately improved residual noise.


    Liquid Spark THD+N THD nth harmonic distortion (A04) FFT 0dBu 300R load - SMPS supplied
    20181005 spark A04 THD+N  THD  nth-HD FFT 300R 4XF.png

    Liquid Spark THD+N THD nth harmonic distortion (A04) FFT 0dBu 300R load - SMPS + Noise Nuke
    20181005 spark A04 THD+N  THD  nth-HD FFT 300R 4XF - noise nuke.png

    Liquid Spark THD+N THD nth harmonic distortion (A04) FFT 0dBu 300R load - BK1623A LPS
    20181005 spark A04 THD+N  THD  nth-HD FFT 300R 4XF - BK1623A LPS.png

    30 Hz residual is reduced by the Noise Nuke; completely gone with an LPS. Distortion differences measured are insignificant between the three.
     
    Last edited: Oct 6, 2018
  8. atomicbob

    atomicbob dScope Yoda

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    reserved.
     
    Last edited: Oct 6, 2018
  9. dBel84

    dBel84 Friend

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    Why does this not surprise me , hats off to Alex
     
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  10. westermac

    westermac Friend

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    @atomicbob Thank you for the measurements! Have you had the chance to try the Liquid Spark with a LPS yet to see if there are any improvements? (EDIT: I missed them) I had both arrive at my office the day before I was to be gone for a week. Very poor timing on my part.
     
    Last edited: Oct 16, 2018
  11. msommers

    msommers High on Epipens

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    Thank you Bob for an immense amount of work. Especially for such a small device!
     
  12. atomicbob

    atomicbob dScope Yoda

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    Thank-you. I suggest you look at post #7 above
     
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  13. roscoeiii

    roscoeiii Acquaintance

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    Any chance we can get some subjective impressions of the power supply differences, even though this is a measurements thread? Apologies if I have missed these elsewhere...
     
  14. atomicbob

    atomicbob dScope Yoda

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    @westermac touched on it here
     
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