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JCALLY JM20 Headphone Dongle Review

Rate this headphone adapter:

  • 1. Poor (headless panther)

    Votes: 2 1.3%
  • 2. Not terrible (postman panther)

    Votes: 0 0.0%
  • 3. Fine (happy panther)

    Votes: 15 9.9%
  • 4. Great (golfing panther)

    Votes: 134 88.7%

  • Total voters
    151

amirm

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This is a review and detailed measurements of the JCALLY JM20 USB-C headphone adapter (DAC and Amp). It is on kind loan from a member and is on sale for US $24.
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter headphone review.jpg

Not much to say about the construction so let's get into measurements. Speaking of that, I finally have a fix for this class of device that allows me to perform full set of measurements like a desktop DAC.

JCALLY JM20 Measurements
Let's start with max volume driving 600 ohm load:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Measurement.png

The CS43131 implementation here delivers excellent, desktop-class performance:
best type c audio dongle adapter headphone review.png

Noise performance is impressive:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Dynamic Range Measurement.png


Distortion is kept at a minimum as well:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Multitone Measurement.png

JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter IMD Measurement.png


I am used to seeing spurious tones in our jitter test but no sign of one here:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Jitter Measurement.png


Linearity is also excellent except for a bit of deviation as levels get higher:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Linearity Measurement.png


Standard filter is used:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Filter Measurement.png

JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Frequency Response Measurement.png


Wideband distortion+noise vs frequency shows elevated response:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter THD vs frequency Measurement.png

This is due to the DAC pushing the noise from audible band into ultrasonic above 50 kHz. Hence the reason when I limit bandwidth to half as much (green/brown lines), we get the excellent response we expect. Here is the spectrum showing the same:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter FFT Measurement.png


The 2 volt maximum output (as seen in dashboard) is better than devices that produce half as much, but can't keep up with those with balanced, 4 volt out:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Power 300 Measurement.png

Most powerful loud headphone adapter usb-c 300 ohm.png


Good current ability means better response into 32 ohm:
JCALLY JM20 CS43131 Audio DAC Type-C To 3.5MM Earphone Adapter Power 32 Measurement.png

Most powerful loud headphone adapter usb-c 32 ohm.png


Conclusions
[Excellent] desktop class DAC performance with a good enough headphone output for $24. Really, what else would you be asking for?

I am happy to recommend the JCALLY JM20 headphone adapter.
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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 
Last edited:
Whether they aced the CS43131 implementation… or they simply avoided ruining a great DAC/Amp chip, well done JCALLY !!! :cool: ……and shame to the ones on the right of the ranking chart.
 
@Hasan Aydin posted a link to an analysis of the potential pops & clicks caused by the Class H mode often used on these CS43131 chips—don’t know about the JM20:

I don’t think it’s a big concern for a dongle used with IEMs or easy-to-drive HPs, but it may be worth knowing.
 
43131 is a legendary all in one chip.
 
FWIW, here are some measurements using the Cosmos APU+ADC:
JCally JM20 1kHz SINAD.png _b_THD+N vs Output Power at 32Ω __b_(Both channels driven, Right channel measured, 20Hz to 20k...png 9_Jitter.png

If you plug in your headphones before you power up the JM20, then the dongle will measure the headphone impedance on startup and limit output voltage accordingly:
Screenshot_20240703-144332_Sheets~2.png

This effectively prevents clipping and is what JCally base their output power specs on (0.95Vrms @32Ω =28mW per channel, same as the US Apple dongle).

You can bypass this impedance sense auto gain mechanism (which Amir likely did by accident) by powering up the JM20 with a high impedance load or an open headphone plug (e.g. headphone adapter), then connecting your actual headphone load.

That way, you can get about twice the output power or +25% perceived volume at 32Ω.
 
Last edited:
Are you driving both channels in the power test and measuring one?
_b_THD+N vs Output Power at 32Ω __b_(Both channels driven, Right channel measured, 20Hz to 20k...png

Data sheet spec is 30mW and you are getting over twice that...
See my edited post for the explanation :)

What is the duration of your THD+N vs Freq at each spot frequency and the duration of the entire test?
These were done semi-automatically using REW's Stepped THD vs Level function, and quite a while ago at that, so I cannot give you precise timing info unfortunately.

Best estimate is 2-3s per step, 1s dead time, maybe 30min total duration?

The dongle was very stable at the time, definitely no thermal buildup issues from what I could tell.
 
FWIW, here are some measurements using the Cosmos APU+ADC:
View attachment 409006 View attachment 409007 View attachment 409005

If you plug in your headphones before you power up the JM20, then the dongle will measure the headphone impedance and limit output voltage accordingly:
View attachment 409008
This is what JCally base their output power specs on (0.95Vrms @32Ω =28mW per channel).

Thanks so much for measuring this ASR favorite, Amir. This is a full circle moment that will help get more eyes on this gem. @staticV3 did a lot to show us what a great bang-for-the-buck dongle this is. There were some great CS43131-based dongles available a few years ago at great prices (including the legendary UGREEN Hi Fi Pro) but now this JCALLY is among the last ones remaining in this form factor and price range.
 
It is considerably more expensive than the Apple dongle, but obliterates it in every respect. Since it is, still relativly speaking, quite cheap, for specific headphones might be well worth the extra money.
 
Best estimate is 2-3s per step, 1s dead time, maybe 30min total duration?

That's great, so well and truly outside the short term (dynamic) capability of the headphone stage in that IC, which is quite impressive.

It's almost too clever for itself.
 
Thanks so much for measuring this ASR favorite, Amir. This is a full circle moment that will help get more eyes on this gem. @staticV3 did a lot to show us what a great bang-for-the-buck dongle this is. There were some great CS43131-based dongles available a few years ago at great prices (including the legendary UGREEN Hi Fi Pro) but now this JCALLY is among the last ones remaining in this form factor and price range.
LoL... @staticV3 is so sharp and smart concerning so many very different topics here @ ASR we should nickname him RaZoR or something cool like that....LoL. He's earned it.
 
Thank you so much for the review @amirm, I already knew the fantastic behavior of this little kid thanks to @staticV3 and proudly own one for almost one year now.

There were some great CS43131-based dongles available a few years ago at great prices (including the legendary UGREEN Hi Fi Pro) but now this JCALLY is among the last ones remaining in this form factor and price range.
I started with the Ugreen in 2021, then continued with this JM20 in 2023 , then again with Sonata BHD in summer 2024, lately again with Kuang Pai Player 3 few days ago. Please, beware of the CS43131 syndrome, it seems to be worse than drugs addiction! o_O
 
New price/performance leader. Pretty amazing! There is little reason to purchase the former reigning champ Apple USB-C dongle anymore, except that it is slightly smaller and $15 cheaper.
 
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