Pass Labs XP-12 Preamplifier Measurements

Discussion in 'Preamps' started by GoldenOne, Jun 18, 2021.

  1. GoldenOne

    GoldenOne Friend

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    APx555 outputting from Sine generator via AudioQuest Mackenzie 1.5m XLR cables into input 1 of the preamp.
    Input impedance set to 200kohm. AC coupled. 20khz AES17 bandwidth limit.


    [​IMG]

    Internals (Photo Credit: HifiKnights http://hifiknights.com/reviews/preamplifiers/pass-labs-xp-12/ )

    [​IMG]


    4v input 4.2v output (closest I could get to unity gain with inbuilt vol control at 90)

    BfdA4j4X2V.png


    4v in 1v out:

    upload_2021-6-18_13-53-15.png

    2v in 1v out:

    upload_2021-6-18_13-54-0.png

    Multitone (Generator set to 4vrms, preamp adjusted to 2v out on 1khz sine (vol 84), then graph offset to have tones at 0dB)

    upload_2021-6-18_13-58-37.png

    Dynamic range with 4v in, vol 84 for 2v out:

    upload_2021-6-18_14-0-31.png

    Dynamic range with 4v in, vol maxed (11.88vrms out)
    Vol is 15dB lower, and we lose about 15dB of dynamic range too:

    upload_2021-6-18_14-0-16.png

    THD+N / Freq 20khz bandwidth:

    vrPOEAYQBL.png

    THD+N / Freq 90khz Bandwidth:

    Bfg68NnUpL.png

    THD+N / Generator Level (Preamp Vol maxed):

    upload_2021-6-18_14-11-4.png

    IMD / Generator Level (Preamp Vol Maxed):

    upload_2021-6-18_14-12-19.png

    Crosstalk:

    [​IMG]

    Frequency Response (+/- 0.079dB deviation in 20-20khz band):

    [​IMG]
     
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  2. GoldenOne

    GoldenOne Friend

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    Reserved
     
  3. spoony

    spoony Spooky

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    Where's the SINAD chart??? I can't read these graphs!
     
  4. enginerd

    enginerd Rando

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    FYI, Desmond at Pass Labs told me that unity gain on the XP-12 is 89 on the volume control.

    Looking forward to your review!
     
  5. TheTalbotHound

    TheTalbotHound Rando

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    What does phase response look like?
     
  6. iFi audio

    iFi audio MOT iFi Audio

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    Lovely stuff done on a great pre. Thanks!
     

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