JCALLY JM20 MAX Headphone Dongle Review

[gogeta01]

Increase your player's asio buffer to more than 1024

I have the same issue. Is there a way to do it generally for Windows?

 

[VicSh]

I have the same issue. Is there a way to do it generally for Windows?

I think this can be done by reflashing it to FiiO KA11 and installing the FiiO USB DAC driver in the system. Then, in the buffer settings, you can increase its size to 2048 samples. This is the largest value.

 

[confucius_zero]

Hey I was wondering if we had total power draw/consumption numbers on this dongle?

 

[VicSh]

Hey I was wondering if we had total power draw/consumption numbers on this dongle?

It's hard to say; I couldn't find any data on this, but I connected the device to a tester, turned the volume all the way up, and got these peak values, though the average was around 1 watt.

 

[confucius_zero]

It's hard to say; I couldn't find any data on this, but I connected the device to a tester, turned the volume all the way up, and got these peak values, though the average was around 1 watt.View attachment 517651

You beauty!

 

[hampestampe]

It's hard to say; I couldn't find any data on this, but I connected the device to a tester, turned the volume all the way up, and got these peak values, though the average was around 1 watt.View attachment 517651

It’s a fun measurement, but the number unfortunately doesn’t tell us very much.
A dongle’s power draw depends just as much on what it’s driving — sensitive IEMs, demanding planars, or simply a line‑out — as on the dongle itself. Without knowing the load, volume, and signal, it’s hard to draw any general conclusions from that 1‑watt reading.

 

[VicSh]

It’s a fun measurement, but the number unfortunately doesn’t tell us very much.
A dongle’s power draw depends just as much on what it’s driving — sensitive IEMs, demanding planars, or simply a line‑out — as on the dongle itself. Without knowing the load, volume, and signal, it’s hard to draw any general conclusions from that 1‑watt reading.

Level and volume—as shown in the screenshot. I’m using the Truthear Crinacle Zero (first generation) as the load. If you have a test track, I can run it through it.

 

[Ahmonge]

Level and volume—as shown in the screenshot. I’m using the Truthear Crinacle Zero (first generation) as the load. If you have a test track, I can run it through it. View attachment 518398

"Ten New Songs" by Leonard Cohen and Rhiannon Giddens. Great album!

 

[hampestampe]

Level and volume—as shown in the screenshot. I’m using the Truthear Crinacle Zero (first generation) as the load. If you have a test track, I can run it through it. View attachment 518398

No worry, I've got same gear in a a box here so I'm able to messure myself.
But I don't get it. Why messure this? It's like asking about fuel consumption of tires. It's more up to the car and the speed of the car. But now, in this case, if the first question was about the jcally jm20 max together with the Crinacle truthear Zero in a specific listening volume it would have made some sense.

 

[Lambdalorian]

Reserved for @RickS to kindly post the specs.

JM20 MAX Features:

1.Model：JCALLY JM20MAX
2.P/N：JM20MAX CS43131 High Performance DAC Decoder Amplifier Adapter
3.DAC: CS43131
4.PCM: 32bits/384KHz
5.SNR/DNR: ＞126dB
6.Crosstalk: -140dB
7.DSD: DSD256 (1bits 11.2MHz
8.Output Load Adaptive: 16 - 600 Ω
9.FR: 20-20000kHz
10.Weight：6.5g±0.5g
11.Length: About 110mm±10
12.Type of wire core: 320 Coils 8 Cores Cable，
13.Color: JM20 MAX Silver

I don't think that there's even the slightest possibility that such dongle only weights 6.5g.

 

[Somafunk]

I don't think that there's even the slightest possibility that such dongle only weights 6.5g.

It won’t be far off, I’d say my jm20max weighs little more (if any) than an eighth (obscure reference that some folk will understand……..brothers unite)

 

[VicSh]

Я не думаю, что существует хоть малейшая вероятность того, что такой адаптер весит всего 6,5 г.

Spoiler: Photo

 

[The Capstan]

I have purchased this little thing a while ago. Still impressed JCALLY engineers have been able to squeeze all the electronics in such a small size and with these results.
One technical question though, it is clear the role of the two main chips inside (DAC + headphone amp). Looking at CS43131 data sheet, I see it managed a number of digital interfaces, including I2S but not USB audio.
So my question -especially for @amirm - is: what is the USB interface used in this dongle? Other DACs use specialised IC like XMOS that are indeed bulky, so certainly not the case here.
Managing USB audio interface is critical for the performance of the DAC with regard to jitter especially and the JCALLY is performing incredibly well on this aspect.

I am doing a webinar on digital interfaces and this topic is indeed of great interest for me.
Thank you.

 

[staticV3]

So my question -especially for @amirm - is: what is the USB interface used in this dongle?

I doubt Amir knows any more than you do on that front.

The quickest way to find out would be to purchase one and crack it open yourself.

You should be able to read the USB bridge's laser marking underneath a microscope, or using your phone's camera provided you have steady hands.

I searched for teardowns online, but it doesn't look like anyone's done it before.

 

[Audionaut]

So my question -especially for @amirm - is: what is the USB interface used in this dongle?

@jkim is probably the best person to answer that question.

On the Distortion of Cirrus Logic CS431xx-Based Devices: A Comparative Review

TL;DR / Changelog [5/20/25] Eleven DAC/HP amp combo devices adopting either the Cirrus Logic CS43131 or CS43198 were tested, and seven of them were found produce the distortion dubbed a "Cirrus hump." Based on measurements from multiple sources (including this review), a list of...

www.audiosciencereview.com

PS
The most likely candidates (used in other Dongles)
Savitech SA9312
Savitech SA9302
Conexant CX31993

 

[MCH]

I am doing a webinar on digital interfaces and this topic is indeed of great interest for me.
Thank you.

I read in the unofficial review thread it uses savitech sa9312l, that like many other bridges typically used in dongles, is very small (3.53*3.53 mm), hardly an issue to make it fit inside a usb-c size enclosure. Nothing special if for instance you open up a smart phone and compare the degree of completely.
Difficult topic for a webinar, for most of these parts the information available is scarce, I bet you will find much more information if you stick to xmos.

 

[The Capstan]

I read in the unofficial review thread it uses savitech sa9312l, that like many other bridges typically used in dongles, is very small (3.53*3.53 mm), hardly an issue to make it fit inside a usb-c size enclosure. Nothing special if for instance you open up a smart phone and compare the degree of completely.
Difficult topic for a webinar, for most of these parts the information available is scarce, I bet you will find much more information if you stick to xmos.

Hi MCH
thank you for this! I have found the data sheet of the SA9312L. Indeed interesting.
A pity the document does not include a block diagram or flow diagram of the internal processing of this chip.

https://www.pawpaw.cn/media/documents/2022-12/SA9312L_V10_201709041.pdf

Alessandro

 

[klirren_65]

It works with the 10 years old Galaxy S5 (Android 7,12). I am really surprised-

 

[somebodyelse]

It works with the 10 years old Galaxy S5 (Android 7,12). I am really surprised

Not sure why you're surprised - UAC2 support has been in Android for a LONG time, and in other linux phones since before Android was released.