Schiit Jotunheim Measurements

Discussion in 'Headphone Amplifier Measurements' started by purr1n, Sep 16, 2016.

  1. purr1n

    purr1n Finding his inner redneck

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    Schiit Jotunheim Measurements

    Too much hype around this amp, so I figured let's take an objective look, beyond all the subjective impressions. NOTE: @atomicbob already provided his measurements. He has better measurement gear than I do, but I wanted to at least provide another look.

    Too many wires danging with alligator clips from 4pin XLR, so excuse the spurious signals. Using the Modi 2 / AKM 4490 DAC as the signal generator (as with previous measurements here, well some may be been from the Modi 2 with the older chip). So SE input from DAC.

    The 1kHz measurement is too close to call - that is to say if there is even any measurable distortion. 99.9db or more below the fundamental and close to the noise floor. Maybe we can say there is a little bit of 2nd order? Like 0.001%? Maybe? Finally, ignore the 12k and 6k spurs on the 50Hz measurement. More 3rd order in 50Hz, but makes sense for balanced. All of my measurements seem to have that - related to the DAC sampling rate 48kHz and resolution of the FFT.

    1kHz @ ~0.550Vrms (using /10 diff. probe) into 330 ohms BALANCED OUT HIGH GAIN
    jot 1k.png

    3kHz @ ~0.550Vrms (using /10 diff. probe) into 330 ohms BALANCED OUT HIGH GAIN

    jot 3k.png

    50Hz @ ~0.550Vrms (using /10 diff. probe) into 330 ohms BALANCED OUT HIGH GAIN
    jot 50Hz.png
     
    Last edited: Sep 17, 2016
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  2. purr1n

    purr1n Finding his inner redneck

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    IMD... NOT... Same conditions as above.

    jot 6-17.png
    jot 5-70.png
     
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  3. Ash1412

    Ash1412 Friend

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    Where was that guy who was looking for distortion-less amps? Maybe we should invite him back just to show him this beast.
     
  4. purr1n

    purr1n Finding his inner redneck

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    Even given the circumstances, mess of exposed wires, and the spurious signals, the results are incredible, especially with IMD. From the first time I've heard it, and this was several years ago, I thought the design was super duper clean and zippy. Measurements don't always show everything, or all aspects of sound quality, but distortion measurement do show subjective "clean" much very so. Schiit's been sitting on this for a while and everybody should be glad that they finally released it. I've been waiting a long time for this.

    Check out @atomicbob's measurements too. His measurements have a far lower noise floor and less spurs - where you can see even more 0.00000 kind of stuff.

    P.S. Doh! I just realized why no evidence of 60Hz, 120Hz, from power...
     
    Last edited: Sep 17, 2016
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  5. murray

    murray Friend

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    Difference in "noise floor" on FFT charts can be due to processing gain (from difference in FFT size). For instance, your 16384 FFT will push the apparent noise floor down by 39dB. Every doubling of the FFT size will add another 3dB of processing gain. I have quickly re-read @atomicbob's measurements, but can't see what size his was. It's just another consideration for "apples to apples" comparison.
     
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  6. murray

    murray Friend

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    Oh, and by the way, great measurement results. It puts years of DIY effort to shame. Time was when one would put in the sweat and toil because the great amps were far too expensive and it was easy to improve on the cheaper offerings.
     
  7. GoodEnoughGear

    GoodEnoughGear Evil Dr. Shultz‎

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    This has to bode well for the 2-channel stuff coming |\/|.
     
  8. purr1n

    purr1n Finding his inner redneck

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    For reference. A comparison of voltage vs. distortion for several amps. The data is spotty, but I sort of took these in my spare time here and there. Sort of a pain without automated / dedicated equipment to do this kind of stuff. The Jotunheim results are limited by noise floor than anything else, so that's why we get screwy results toward the lower voltage levels.

    Dummy load of 330 ohms. BTW, 500 mV output into Sennheiser HD650s is very loud!

    Voltage RMS vs THD, Load = 330 ohms, Highest Gain used
    X axis = mV, Y axis = THD (0.01 = 1%)

    powercomp.png
     
    Last edited: Sep 17, 2016
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  9. Walderstorn

    Walderstorn Friend

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    This is incredibly impressive.
     
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  10. Bitter

    Bitter Acquaintance

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    Indeed, didn't notice the logarithmic scale at first.
     
  11. schiit

    schiit SchiitHead

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    Yaaaay! I did something right (for a change.) (Maybe.)

    Brackets indicate typical engineering thoughts.
     
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  12. schiit

    schiit SchiitHead

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    (And, Marv, it's a pain with or without automated equipment. You have to watch the Stanfords to make sure you didn't change reference values (very easy to do) or that it didn't crash after a couple of automated SNR runs (or similar). "Hey, I got 126.1dB SNR!" sometimes means, Yeah, referenced to 40V RMS," or "Hey, the analyzer has taken a dump!" Actually, usually that's what a measurement like that means.)
     
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  13. SSL

    SSL Friend

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    ...so let's make some more, he says.
     
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  14. purr1n

    purr1n Finding his inner redneck

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    Heeheehee. Well, I just wanted to make sure we were being objective about it too. At least with these results, if anybody accused us of being biased or of groupthink, we can retort back that they have shitty ears. I'm not surprised at these results, I heard it a mile away. So did many others.
     
    Last edited: Sep 17, 2016
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  15. Armaegis

    Armaegis Friend

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    As an engineer and teacher, this is my constant insecurity. Like okay, I did a thing, it seems to work, people seem to like it... or do they??? or hey I just tutored your kid for the last month in trigonometry and they've got a test coming up, they should be fine... I hope...
     
  16. Poleepkwa

    Poleepkwa Friend

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    I assume Schiit will never offer any of their amps as DIY kits? I would love to build something like this...
     
  17. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    There are a few amps with pretty good specs. Take Sjostrom QRV08 for example or Neurochrome HP-1.
     
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  18. AstralStorm

    AstralStorm Friend

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    Can we get the phono module tested? This would simplify a step in my work while being a great DAC and amp too!

    Now... pity there is no switch on the RIAA module. But maybe someone can make a variant flat XLR module.
     
    Last edited: Jan 6, 2017
  19. AstralStorm

    AstralStorm Friend

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    Never mind, the purpose of the RIAA module is for phono listening.

    In case I would want one, which preamp would do RIAA and be comparable? Yet upcoming?
     
  20. RonShaun

    RonShaun Rando

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    So I was wondering, if the jotunheim has such good distortion measurements, what makes it so "shrilly" compared to other amps? Take for example, the jotunheim paired the hd 800: the amp somehow amplifies that annoying 6Khz peak rather than leave it be. Can someone explain why this happens?
     
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