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JCALLY JM20 MAX Headphone Dongle Review

Rate this portable DAC & HP Amp:

  • 1. Poor (headless panther)

    Votes: 4 2.1%
  • 2. Not terrible (postman panther)

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

    Votes: 20 10.4%
  • 4. Great (golfing panther)

    Votes: 168 87.5%

  • Total voters
    192
So, I pick this one exact model and it work fantastic with my DELL laptop (AKG K371 headphones) sound quality is fantastic and output capabilty awesome. But I can not achieve it to work if attached directly to my OPPO smartphone, excuse my ignorance, but why it can be?
Did you anable OTG on the phone? On many phones you have to enable it every time you want to use it and it goes off after a specified time when no otg device is connected.
 
I wouldn’t be concerned about this — it feels slightly warm, not hot, so it’s nothing to worry about. The braided cable might appear a bit delicate, but considering the cost of the device, replacing it wouldn’t be a major issue if it ever became necessary.
You can reinforce the cable with some heath shrink tube just in case.
 
My subjection impressions with the JM20 Max and my Fiio JA11 (only 30mW/Ch). Uncontrolled listening so take it with a grain of salt:

With my Truthear Red or Zero 2, differences between both aren't night and day, but the Max has fuller bass, more ethereal vocals and treble.
I didn't expect to find any differences between both before I tried the Max, since both IEMs are pretty easy to drive, output impedances for both dongles are ~0.5 ohm and I don't listening loud at all.
 
Someone earlier posted that JCALLY is a generic, “no-name” brand in China. It certainly has that kind of name—something that has had zero marketing thought given to it. However, I do not think this is just an anonymous reference design, just rebadged and repackaged by JCALLY. The engineering that went into it is just outstanding, given the size constraints the designer(s) were faced with. This isn’t even taking into account its bargain basement price.
 
Someone earlier posted that JCALLY is a generic, “no-name” brand in China. It certainly has that kind of name—something that has had zero marketing thought given to it. However, I do not think this is just an anonymous reference design, just rebadged and repackaged by JCALLY. The engineering that went into it is just outstanding, given the size constraints the designer(s) were faced with. This isn’t even taking into account its bargain basement price.
Several of the JCally dongles are based in TTGK modules (https://www.szttgk.com/en). I don’t know if the JM20-Max is one of them, but the point is that there are OEMs out there who are highly specialized in developing this kind of modules, but are not selling directly to the public—in TTGK’s case, they don’t even manufacture the shell of the dongle.
They know their stuff…
 
I got this dongle after reading this article and Jkim's to replace the famed Apple Dongle (US version) for less than $19, to pair with my Samson SR850 for PC listening.
Since I mess around with BRIRs and surround sound virtualization, which demands severe preamp cuts to prevent clipping (upwards of -10dB), I sorely need more output than the Apple Dongle can provide. Enter the JM20 Max. It is an excellent headphone DAC that's worth every penny. Furthermore, maybe my ears are fooling me but it also sounds a tad cleaner and "fuller" compared to the Apple Dongle, which I suspect comes from not pushing the DAC to its absolute limit (or better noise rejection?). With approx. -12db preamp, I usually set the Windows volume slider at 30-40% for long-term listening.
However, there's one thing new buyers must look out for. This thing gets HOT under use. The moment I plug it in it becomes warm to the touch. After 30-45 minutes of listening, it becomes surprisingly hot (I estimate around 40-45C), not something you'd expect from a tiny USB-C dongle. Such a high output, I believe, comes with higher power consumption and heat generation. Since I was kinda worried about the longevity of the dongle (and learning that someone's dongle suddenly died earlier in the thread), I put a small piece of computer thermal pad (like these) on top of where the chips are.
So far I'm pleased with this purchase and might write an update once I've spent some more time with it.
 
I got this dongle after reading this article and Jkim's to replace the famed Apple Dongle (US version) for less than $19, to pair with my Samson SR850 for PC listening.
Since I mess around with BRIRs and surround sound virtualization, which demands severe preamp cuts to prevent clipping (upwards of -10dB), I sorely need more output than the Apple Dongle can provide. Enter the JM20 Max. It is an excellent headphone DAC that's worth every penny. Furthermore, maybe my ears are fooling me but it also sounds a tad cleaner and "fuller" compared to the Apple Dongle, which I suspect comes from not pushing the DAC to its absolute limit (or better noise rejection?). With approx. -12db preamp, I usually set the Windows volume slider at 30-40% for long-term listening.
However, there's one thing new buyers must look out for. This thing gets HOT under use. The moment I plug it in it becomes warm to the touch. After 30-45 minutes of listening, it becomes surprisingly hot (I estimate around 40-45C), not something you'd expect from a tiny USB-C dongle. Such a high output, I believe, comes with higher power consumption and heat generation. Since I was kinda worried about the longevity of the dongle (and learning that someone's dongle suddenly died earlier in the thread), I put a small piece of computer thermal pad (like these) on top of where the chips are.
So far I'm pleased with this purchase and might write an update once I've spent some more time with it.
Isn't the thermal pad supposed to couple with a heatsink? I mean, does it dissipate heath by itself?
 
I got this dongle from ali for roughly 17 bucks with discounts, hoping it would replace my Soundblaster Z and give my GPU some extra breathing room, as the soundcard is like a few millimeters from my GPU. All is fine with the dongle, got enough juice to power my beyerdynamics DT770 Pro 250ohm, except theres some frequently occurring annoying popping/static at start or end of vocals, that I can't get rid of. I tried all USB ports on my PC, tried it without the usb extension cable I use it with, tried it with EQ off and on, even tried it on my phone and it still occurs. Doesn't really happen on my soundblaster or on my other cheap 5$ dongle with ALC5686... Anyone else who has this problem?

Note: the popping/static (don't really know how to exactly describe it) isn't earpiercing or loud, but it's really annoying, that I had to pop back in my soundblaster.
 
Isn't the thermal pad supposed to couple with a heatsink? I mean, does it dissipate heath by itself?
Just a few hours prior I was just looking at my old (Socket 775) Scythe Ninja radiator lying around and thinking about how funny would a JM20 Max strapped to it look :p

That said attaching even just a thin aluminium plate to that pad would likely improve it a lot, pads are ok at transfering, but if I vaguely recall hearsays right alu has faster dissipation rate/rapid cooling than even copper (which I think had better heat conductivity and capacity?).

Doesn't really happen on my soundblaster or on my other cheap 5$ dongle with ALC5686... Anyone else who has this problem?
I've it with regular JM20, which I was a bit on the edge when ordering instead of JM20 Max, as Max was supposed to be measured click free according to one user here.

On a side note, I also have Z, and was going to use JM20 to see if I can perceive measured 10dB SiNAD + jitter difference, and hence possibly use it as a temporary replacement as a DAC driving L30 II. In my case I would leave Z anyway as I have good clearance to GPU and an additional 2.5Vrms output (+ADC +7.1 outputs) is always welcomed. Honestly I like that CS4398 card, and whenever I see someone on reddit blasting internal soundcards for noise and interference, I use it as an example since it is 102dB SiNAD made in 2012. Certainly big thanks for Amirm for measuring Z, the knowledge about its output power and 22Ohm output impedance are helpful for reference.
 
I got this dongle from ali for roughly 17 bucks with discounts, hoping it would replace my Soundblaster Z and give my GPU some extra breathing room, as the soundcard is like a few millimeters from my GPU. All is fine with the dongle, got enough juice to power my beyerdynamics DT770 Pro 250ohm, except theres some frequently occurring annoying popping/static at start or end of vocals, that I can't get rid of. I tried all USB ports on my PC, tried it without the usb extension cable I use it with, tried it with EQ off and on, even tried it on my phone and it still occurs. Doesn't really happen on my soundblaster or on my other cheap 5$ dongle with ALC5686... Anyone else who has this problem?

Note: the popping/static (don't really know how to exactly describe it) isn't earpiercing or loud, but it's really annoying, that I had to pop back in my soundblaster.
Increase your player's asio buffer to more than 1024
 
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