Measurements: Mojo, AK100II, Sony ZX2, iPhone 6

Discussion in 'Portable and Other Gear Measurements' started by purr1n, Jun 12, 2016.

  1. purr1n

    purr1n Finding his inner redneck

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    Measurements: Mojo, AK100II, Sony ZX2, iPhone 6 Plus

    These are not comparable to the LH Labs GOV2 measurements. I did something a little bit different here because I wanted to evaluate performance for IEMs. I used 20.7 ohm load because these seemed like a good compromise for many types of IEMs which have nominal impedances ranging from 12 to 50 ohms.

    The voltage output I standardized on was about 45-50 mVrms for the distortion tests 1kHz and 50kHz. At this voltage level, the Andromeda IEM outputs about 100db more or less. Note that the plots say 4.5-5 mVrms. This is because I am using a differential probe with a 10 divider. The differential probe has a higher noise floor but tends to be a lot cleaner from artifacts and spurs of which there are many. I also couldn't be exact on the output because of the coarse volume controls on some of these portable units, especially the iPhone 6. But the levels are close enough to where the results should be comparable.

    Finally, for the last set of plots, I wanted to "crank" things up to see how much power these portables really had. The results were a bit surprising. It turns out the ZX2 with the "weaksauce power" of the S-Master myths might be false.
     
    Last edited: Jun 18, 2016
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  2. purr1n

    purr1n Finding his inner redneck

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    1kHz tone. Load is 20.7 ohms. 10 divider
    Note: There are some
    artifacts and spurs. Take the tiny oddball stuff with a grain of salt. They probably aren't really there. I don't have lab conditions at home. The ZX2 measures the worst of the bunch, but I am not sure I can hear -70db down on the 3rd harmonic. The Mojo is super clean.

    In the end, it does not matter. Distortion is infitissmal, at least into this load. There are no strange high order harmonics. FYI, The Andromeda IEM outputs about 100db at this voltage output.


    AK100II
    AK100II 1k.png

    iPhone 6
    IP6 1kHz.png

    Sony ZX2
    ZX2 1k.png

    Chord Mojo
    Mojo 1k.png
     
    Last edited: Jun 18, 2016
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  3. purr1n

    purr1n Finding his inner redneck

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    50Hz tone. Load is 20.7 ohms. 10 divider

    AK100II
    AK100II 50Hz.png

    iPhone 6 Plus
    IP6 50Hz.png


    Sony ZX2
    ZX2 50Hz.png

    Chord Mojo
    Mojo 50Hz.png
     
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  4. purr1n

    purr1n Finding his inner redneck

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    White Noise 44.1kHz
    All of these devices go from 20 to 20kHz without a problem. The ZX2 has the most gentle filter. The Mojo zips down with a super high slope. Nothing out of the ordinary beyond the audio band. It looks like the Mojo might have a very slight treble rolloff before the shelf.

    AK100II
    AK100II WN.png

    iPhone 6 Plus
    IP6 WN.png

    Sony ZX2
    ZX2 WN.png

    Chord Mojo
    Mojo WN.png
     
    Last edited: Jun 12, 2016
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  5. purr1n

    purr1n Finding his inner redneck

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    Cranking It Up. ~420 mVrms. 20.7 ohm Load. 10 divider
    Obviously the limiting factor here is gain / interface of the portable unit. Note that the levels are not exact because of the coarseness of volume control. The Sony ZX2 maxxed out to reach this level. The iPhone 6 was one notch from being maxxed out. It's very important to note that the iPhone 6 reached clipping on this load just after this notch at max output. (You don't even want to see this plot). Mojo seemed to have plenty of steam.

    Two surprises: The AK100II started to clip rather early. The Sony ZX2 has more power (at least into this load) than what urban legends and myths would have us believe.


    AK100II
    AK100II max.png

    iPhone 6 Plus
    IP6 max.png

    Sony ZX2
    zx2 max.png

    Mojo
    Mojo max.png
     
    Last edited: Jun 18, 2016
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  6. purr1n

    purr1n Finding his inner redneck

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    OK, finished with all of the measurements.
     
  7. briskly

    briskly Friend

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    What's the output impedance for these things? ZX2 is one I'd like to know in particular.
     
  8. purr1n

    purr1n Finding his inner redneck

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    Last edited: Jun 12, 2016
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  9. Warrior

    Warrior Friend

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    Interesting stuff, at least what I understand. Thanks for sharing bro.
     
  10. pila405

    pila405 Rando

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    In all the measurements I find of the Chord Mojo it manages to impress. Why did they have to make it so ugly, though?
    From the Andromeda measurements, it seems like the Mojo's output impedance is lowest - what did you measure?

    Thanks for posting the measurements!
     
  11. purr1n

    purr1n Finding his inner redneck

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    Mojo output Z was effectively zero. Like zero point zero something. Getting super precise impedance measurements is hard without first getting precision measurements of the wires, reference resistors, etc. But yeah, it's effectively zero.
     

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