Cavalli Liquid Gold X technical measurements

Discussion in 'Headphone Amplifier Measurements' started by atomicbob, Oct 17, 2020.

  1. atomicbob

    atomicbob dScope Yoda

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    Cavalli Liquid Gold X (LauX) 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, Micsig DP10013 balanced probe
    2. Balanced XLR cables Belden 1800F with Neutrik 110R AES connectors (if used)
    3. Single Ended cables Audioblast HQ-1 1.5 ft with Rean RCA connectors
    4. 30 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 to achieve 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. LAuX gain switch set to low gain unless otherwise noted

    Measurements 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.

    Cavalli Liquid Gold X (LauX)
    Measurements commenced after 1 hour of warmup.
    Measurements sets were performed over a period of several days, three measurement sets taken over several months.

    Index
    Post 1 - measurement setup description, highlights
    Post 2 - 300 ohm load Bal input Bal output
    Post 3 - 30 ohm load Bal input Bal output
    Post 4 - 300 ohm load SE input SE output
    Post 5 - 30 ohm load SE input SE output
    Post 6 - reserved for corrections or additional data

    Setup picture:
    DSC_0375_small.jpg

    Listening picture:
    DSC_0376_small_cropped.jpg

    Output Impedance measured:
    Bal 300R: 0.18 ohm
    Bal 30R: 0.17 ohm
    SE 300R: 0.18 ohm
    SE 30R: 0.19 ohm

    Notable highlights:
    Liquid Gold X (LAuX) has been optimized for balanced operation. It provides great performance Single Ended but clearly best performance is attained in balanced mode. If contemplating this amplifier, balanced headphone cables will prove a wise choice. LAuX falls squarely in the transparent design camp. Attributes of low output impedance, low residual noise, low distortion, high bandwidth, fast transient response definitely contribute to extraordinarily clean performance.

    Typical of Cavalli designs bandwidth is quite wide, DC to > 500KHz with 30R load and DC to > 600KHz with 300R load.
    Dynamic Range is greater than 113 dB relative to 0 dBu in balanced mode.
    Note particularly the exceptionally low IMD for all two tone tests, not just 19+20 KHz which is impressive.
    Note too, the fast square wave response transitions times do not ring, also very impressive.

    Dr. Cavalli has earned a well deserved reputation for amplifier design excellence.
     
    Last edited: Oct 17, 2020
  2. atomicbob

    atomicbob dScope Yoda

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    300 ohm load Bal input Bal output

    LauX A04 THD+N THD nth-HD FFT 300 ohm load Bal input Bal output
    20190923 LAuX A04 THD+N  THD  nth-HD FFT 300R 4XF - 4+HD+N with 60Hz.png

    LauX 50 + 7000 Hz 300 ohm load Bal input Bal output - Left Channel
    FFT_2_L1T13_1_A.png
    Exceptionally clean two tone IMD!!!

    LauX Gain Linearity 300 ohm load Bal input Bal output - Left Channel
    G2_L1T3_1_A.png

    LauX THD+N vs Frequency 300 ohm load Bal input Bal output - Left Channel
    G2_L1T5_1_A.png

    LauX Residual Noise 300 ohm load Bal input Bal output - Left Channel
    FFT_2_L1T16_1_A.png

    LauX Square Wave 2000mV 10mS/div Bal input Bal output - Left Channel
    20190923 SigGen LiqGoldX 20 Hz square 2000mVpp 10mS div 100KHz filter 300R Bal.png

    LauX Square Wave 2000mV 250nS/div Bal input Bal output - Left Channel
    20190923 SigGen LiqGoldX 20 Hz square 2000mVpp 500nS div 20MHz filter 300R Bal - BW calc.png
    BW estimate = 0.35 / t rise 10% to 90%
    0.35 / 583.0 nS = 600.3 KHz
    No ringing on transition!!!

    Noise in the square wave response is from the MicSig DP10013 balanced probe, not the LAuX. I now use a Cal Test CT2593-2 balanced probe but at the time of LAux measurements I did not have the CT2593-2. This applies to all LAuX square wave responses posted below.

    MicSig DP10013 vs Cal Test C2593-2 residual noise with 50R load between probe inputs.
    20201012 CT2593-210x  ch A  DP10013 50x ch B 50R input.png

    MicSig DP10013 vs Cal Test C2593-2 square wave response direct from SDG 2042X signal generator output.
    20201012 CT2593-210x  ch A  DP10013 50x ch B sig gen 20 Hz sqr 10mS div.png

    Complete 300 ohm load Bal input Bal output analysis and square wave reports pdf attached
     

    Attached Files:

    Last edited: Oct 17, 2020
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  3. atomicbob

    atomicbob dScope Yoda

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    30 / 32 ohm load Bal input Bal output

    LauX A04 THD+N THD nth-HD FFT 30 ohm load Bal input Bal output
    20190923 LAuX A04 THD+N  THD  nth-HD FFT 30R 4XF - 4+HD+N with 60Hz.png

    LauX 50 + 7000 Hz 32 ohm load Bal input Bal output - Left Channel
    FFT_2_L1T13_1_A.png

    LauX Gain Linearity 32 ohm load Bal input Bal output - Left Channel
    G2_L1T3_1_A.png

    LauX THD+N vs Frequency 32 ohm load Bal input Bal output - Left Channel
    G2_L1T5_1_A.png

    LauX Residual Noise 32 ohm load Bal input Bal output - Left Channel
    FFT_2_L1T16_1_A.png

    LauX Square Wave 2000mV 10mS/div Bal input Bal output - Left Channel
    20190923 SigGen LiqGoldX 20 Hz square 2000mVpp 10mS div 100KHz filter 30R Bal.png

    LauX Square Wave 2000mV 250nS/div Bal input Bal output - Left Channel
    20190923 SigGen LiqGoldX 20 Hz square 2000mVpp 500nS div 20MHz filter 30R Bal - BW calc.png
    BW estimate = 0.35 / t rise 10% to 90%
    0.35 / 677.5 nS = 516.6 KHz

    Complete 32 ohm load Bal input Bal output analysis and square wave reports pdf attached
     

    Attached Files:

    Last edited: Oct 17, 2020
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  4. atomicbob

    atomicbob dScope Yoda

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    300 ohm load SE input SE output

    LauX A04 THD+N THD nth-HD FFT 300 ohm load SE input SE output
    20190923 LAuX A04 THD+N  THD  nth-HD FFT 300R SE - 4+HD+N with 60Hz.png

    LauX 50 + 7000 Hz 300 ohm load SE input SE output - Left Channel
    FFT_2_L1T13_1_A.png

    LauX Gain Linearity 300 ohm load SE input SE output - Left Channel
    G2_L1T3_1_A.png

    LauX THD+N vs Frequency 300 ohm load SE input SE output - Left Channel
    G2_L1T5_1_A.png

    LauX Residual Noise 300 ohm load SE input SE output - Left Channel
    FFT_2_L1T16_1_A.png

    LauX Square Wave 1000mV 10mS/div SE input SE output - Left Channel
    20190923 SigGen LiqGoldX 20 Hz square 1000mVpp 10mS div 100KHz filter 300R SE.png

    LauX Square Wave 1000mV 250nS/div SE input SE output - Left Channel
    20190923 SigGen LiqGoldX 20 Hz square 1000mVpp 500nS div 20MHz filter 300R SE - BW calc.png
    BW estimate = 0.35 / t rise 10% to 90%
    0.35 / 546.1 nS = 640.9 KHz

    Complete 300 ohm load SE input SE output analysis and square wave reports pdf attached
     

    Attached Files:

    Last edited: Oct 17, 2020
  5. atomicbob

    atomicbob dScope Yoda

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    30 / 32 ohm load SE input SE output

    LauX A04 THD+N THD nth-HD FFT 30 ohm load SE input SE output
    20190923 LAuX A04 THD+N  THD  nth-HD FFT 30R SE - 4+HD+N with 60Hz.png

    LauX 50 + 7000 Hz 32 ohm load SE input SE output - Left Channel
    FFT_2_L1T13_1_A.png

    LauX Gain Linearity 32 ohm load SE input SE output - Left Channel
    G2_L1T3_1_A.png

    LauX THD+N vs Frequency 32 ohm load SE input SE output - Left Channel
    G2_L1T5_1_A.png

    LauX Residual Noise 32 ohm load SE input SE output - Left Channel
    FFT_2_L1T16_1_A.png

    LauX Square Wave 1000mV 10mS/div SE input SE output - Left Channel
    20190923 SigGen LiqGoldX 20 Hz square 1000mVpp 10mS div 100KHz filter 30R SE.png

    LauX Square Wave 1000mV 250nS/div SE input SE output - Left Channel
    20190923 SigGen LiqGoldX 20 Hz square 1000mVpp 500nS div 20MHz filter 30R SE - BW calc.png
    BW estimate = 0.35 / t rise 10% to 90%
    0.35 / 578.0 nS = 605.5 KHz

    Complete 32 ohm load SE input SE output analysis and square wave reports pdf attached
     

    Attached Files:

    Last edited: Oct 17, 2020
  6. atomicbob

    atomicbob dScope Yoda

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    reserved for corrections or additional data.
     
    Last edited: Oct 17, 2020
  7. purr1n

    purr1n Finding his inner redneck

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    Interesting that 7kHz 2nd harmonic is higher than the H2 at 50Hz or 1kHz. All academic though.
     
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