JCALLY JM20 MAX Headphone Dongle Review

[Lambda]

Amazing little DAC! Now imagine if they had a Mono mod for driving Balanced loads.
This Way we would hypothetically end up with 5V rms and ~124dB SINAD (for 22€) (per channel)

Now also Add the cost Galvanic isolation like Adum4166 Adum3166 USB 2.0 Isolator 480Mbps ~30€

And you would have an Isolated USB to XLR Dongle with SOTA Performance for ~60€

(of causes there are more problems like synchronization of 2 usb audio devices and so on.)

but just to show how obsolete most of the desktop class DACs are

 

[peniku8]

Amazing little DAC! Now imagine if they had a Mono mod for driving Balanced loads.
This Way we would hypothetically end up with 5V rms and ~124dB SINAD (for 22€) (per channel)

Best-case SINAD for this dongle is ~114dB. Doubling channel count nets you 3dB more S/N so you get 117dB SINAD at best (signal sums coherently +6dB and noise sums incoherently +3dB, so you get +6dB more signal, which is a doubling of voltage, but only 3dB better S/N).
You can do this easily with any stereo DAC. Send a signal to the left output and send the same signal but with inverted phase to the right output. That's how I'm using my unbalanced MiniDsp 2x4HD as balanced device.

 

[alekksander]

goodie!

 

[Lambda]

Best-case SINAD for this dongle is ~114dB. Doubling channel count nets you 3dB more S/N so you get 117dB SINAD at best (signal sums coherently +6dB and noise sums incoherently +3dB, so you get +6dB more signal, which is a doubling of voltage, but only 3dB better S/N).
You can do this easily with any stereo DAC. Send a signal to the left output and send the same signal but with inverted phase to the right output. That's how I'm using my unbalanced MiniDsp 2x4HD as balanced device.

Your right. i did some how mixed up the numbers while writing this post.

what i wanted to say is ~112dB Sinad + the 3db Gain from summing the incoherent signals
so it's ~115dB or best cases 117dB SINAD
Still impressive.

And if this would Come as small dong and with galvanic isolation (maybe toslink) it would be awesome.

 

[JRowland]

That's right.

@MC_RME also reported his output impedance measurements in my review thread.

It seems that many members read Amir's reviews only.

Although I understand why, this is somewhat discouraging as my motivation was to share valuable findings with more fellow audio enthusiasts...

Thank you for your post and review, I have one in the mail as a result. I like reading multiple reviews and the discussions that result, usually helps me filter better. The price might go up from all the eyeballs that this one will bring so I’m glad I saw yours!

 

[mc.god]

cant find out what the difference is between the MAX and PRO version. anyone can elaborate?

MAX: CS43131 + SGM8262 driver op-amp, more power than original JM20 tested here https://www.audiosciencereview.com/...ds/jcally-jm20-headphone-dongle-review.58749/
PRO: CS43131, no additional op-amp, different usb bridge that include an ADC to support input for calls and a dsp for hardware PEQ, same power than JM20

 

[Ajax]

So you can pay $1500 for an Astell & Kern Kann Ultra DAP, and have the hassle of an extra device to carry around, or you can pay only $25 for the JM20 (that performs better) and simply connect it to your smart phone, which 95% of the population carry at all times.

Am I missing something?

 

[Millo_jp]

I'm glad to know that I wasn't wrong when I bought it, I thought the non-max version was better. I have it connected to a FOSI BT30D PRO, and there is a huge improvement over Bluetooth. The difference is not only in the sound quality but also in the amount of volume

 

[beefkabob]

$21 today. $72 tomorrow. $54 the next. It makes me just not wanna buy a great product.

 

[Jean-Paul Petrosyan]

Thank you for the review!

No reason to measure multitone performance at different signal levels?

Asking since I've seen a significant amount of CS based products exhibiting peculiar behavior in these tests.

 

[Barrelhouse Solly]

I use one in my car. I love it. Having been an audio cheapskate for over 50 years I'm delighted to see the proliferation of gear like this.

 

[Bow_Wazoo]

It's a A&K killer

 

[jcarys]

Thanks, Amir, I also bought one from Crinacle's shop. I guess I can quit complaining about the Sony DAP's SNR with this. Now whether I hear the difference will be interesting.

 

[markanini]

I agree with your point. But my concern is a litte different. Being an audiophile for so many years and listening to so much stuff. I am still confused.

Some audio manufacturers have their house sound.
example Yamaha have their typical tonal color and punch. People who love Yamaha knows what I am talking about.
this statement is somewhat true with other companies as well.

But chinese manufacturers are not focusing on sound characteristics/tonal color to get associated with their brand. Their main goal is to be as neutral as possible.
One of the most engaging sound amplifier that I have heard was from Nakamichi Japan [1990s era]. It was fairly distorted sound and far away from neutrality. But still was the most enjoyable.

My main concern is that we are fighting to get the most refined form of water. But does drinking refined water give same level of Satisfaction that we get from drinking Juice?

The music creator, not your amp, puts the “juice” in the sound. Engineers and producers shape every note—subtle tweaks or big effects—in neutral studios to get their mix just right. If your amp adds its own color, it fights their work and twists the mix they intended! That’s why audio gear needs to play the source clean, no alterations. You want the artist’s juice, not your amp’s spin, right? To keep the sound true.

 

[beefkabob]

The music creator, not your amp, puts the “juice” in the sound. Engineers and producers shape every note—subtle tweaks or big effects—in neutral studios to get their mix just right. If your amp adds its own color, it fights their work and twists the mix they intended! That’s why audio gear needs to play the source clean, no alterations. You want the artist’s juice, not your amp’s spin, right? To keep the sound true.

Historically, studios have had far from neutral gear. Most audio engineers are like everybody else, usually not knowing what they're getting and watching subjective shit YouTube reviews before buying gear. My friend wrote many an audio hardware and software review over many years for major magazines and has written several books and manuals for audio software. I can guarantee you that he was not measuring any of the hardware. It was all 100% subjective.

 

[markanini]

Historically, studios have had far from neutral gear. Most audio engineers are like everybody else, usually not knowing what they're getting and watching subjective shit YouTube reviews before buying gear. My friend wrote many an audio hardware and software review over many years for major magazines and has written several books and manuals for audio software. I can guarantee you that he was not measuring any of the hardware. It was all 100% subjective.

You’re right-studios often use non-neutral gear, and that’s still true today! Engineers pick colored tools to shape the sound, then fine-tune the mix in controlled, neutral studios. Subjective judgment might guide many choices, but the final mix is vetted for accuracy. If your playback gear adds its own color, it messes with that mix! Neutral playback keeps the sound clean and true. Sticking to that for the real deal.

 

[xanalog]

Sounds excellent but I do get static on my phone, maybe need to clean the USB port

imo: Sounds contradictory.

 

[Oso Polar]

My main concern is that we are fighting to get the most refined form of water. But does drinking refined water give same level of Satisfaction that we get from drinking Juice?

I don't think your comparison is valid - DACs/amps/speakers/headphones etc. are just means to listen to music (or whatever other sound). So, using your analogy, they will be something like cups. E.g. a cup with a taste of orange juice. You drink water from it - tastes like water with orange juice. You drink coffee from it - tastes like shit coffee with orange juice etc. And you can never drink from it anything that tastes like the original beverage. Even orange juice will taste like an orange juice on steroids.

 

[napfkuchen]

My smartphone doesn't have a 3,5mm-out, so this is a superb upgrade. Thanks for the review!

 

[Cadillacofminds]

So do I now have to feel not-so-smart "lugging" around my Fosi DS2? I too wanna know if perchance power consumption is a drawback, or reliability? ...Man I'm under the weather, stoned, not feeling like reading the thread started by our good-fellow member