(Unofficial) Review of JCALLY JM20 MAX: USB-C Headphone Dongle with High Unbalanced Output Power

[jkim]

I've been using this DAC for a couple of weeks now - with TRUTHEAR GATE IEMs and haven't been able to use the volume up / down or pause / action button on the in-line controls (2-pin cable that shipped with the IEMs), on a Pixel 10. I don't have anything else to test with at this stage. Anyone else had issues with in-line basic controls?

The JM20 Max does not support in-line controls.

 

[o0o]

No, the FiiO KA11 FW does not reverse the polarity of the JM20 Max

People will be reluctant to take the risk of bricking it. So, I served as your guinea pig. Flashing the FiiO KA11 firmware to the JM20 Max was successful. Now the dongle is recognized as "FIIO KA11." But unfortunately, its filter setting cannot be changed from the Android FiiO app. It is changed on screen but has no actual effect (and whenever plugged in again the setting reverts back to default). Recording of test signals indicates it's not in the NOS mode.

Not sure if this is the case even with the FiiO KA11 (i.e., a bug of the firmware itself), though. At least, it works just as before. The only difference (other than the device label) is that it has a fade-in effect when audio starts after idling, which was not present with the stock FW. FiiO seems to always consider power saving as an important feature.

Now it cannot go back to its stock FW.

So I flashed the FiiO KA11 firmware to the JM20 Max and it's a definitive upgrade for my use cases. Thank you @jkim for the risk-taking and all the feedback!

Added features:
- FiiO driver support for Windows: ASIO, Native DSD256, a setting to switch the fade-in "effect" off in the driver control panel,
- ability to switch between 5 PCM-filters* in FiiO Control app for Android, including NOS.

Old inherited bugs (might be limited to my jm20 max only):
- occasionally there is no sound on 1st connection, requires re-plugging the cable,
- DSD256 remains glitchy on Android (Neutron player), DSD128 is fine,
- with Windows native UAC2.0 drivers there are regular dropouts in DSD mode when playing DSD64 / DSD128 using WASAPI exclusive DoP (with FiiO ASIO drivers everything is playing fine).

Limitations:
- FiiO Control app cannot store or read any settings from JM20 Max's hardware, including PCM-filter setting*.
(be warned, I did not try switching to UAC 1.0, and do not know the effect of switching. it could potentially break the device or simply have no effect.)
- Windows volume control has no effect in some cases when FiiO driver is used.
(in such case the volume can be changed from the driver's control panel.)

*PCM-filter switching does actually work but only if used on an Android device and only while jm20 max is connected to it. Once unplugged the setting is lost and the default "Min Phase Fast Roll-Off" filter will be used on the next connection to any device.

Here's how I use it:
- connect JM20 Max
- open Neutron app and allow it to access FiiO KA11 (the new name of JM20 Max)
- start the playback (not a must at his point, just a logical step)
- open FiiO Control app and allow the access as well
- change the filter settings (by default the NOS filter will be shown, simply ignore that, since the app cannot read the setting from the JM20 hardware and uses NOS as default value, while the actual setting on the device is still Min Phase Fast Roll-Off. Just tap on any filter and it will work as intended.)

Everything is the same as before, including the max output level, frequency response, filter (fast roll-off low latency / min phase), and response to multitone and other test signals.

+1

JM20 Max is a great device for the price, but I will go with FiiO KA11 or its successor next time because of the aforementioned features and arguably better durability.

 

[jkim]

So I flashed the FiiO KA11 firmware to the JM20 Max and it's a definitive upgrade for my use cases. Thank you @jkim for the risk-taking and all the feedback!

Added features:
- FiiO driver support for Windows: ASIO, Native DSD256, a setting to switch the fade-in "effect" off in the driver control panel,
- ability to switch between 5 PCM-filters* in FiiO Control app for Android, including NOS.

Old inherited bugs (might be limited to my jm20 max only):
- occasionally there is no sound on 1st connection, requires re-plugging the cable,
- DSD256 remains glitchy on Android (Neutron player), DSD128 is fine,
- with Windows native UAC2.0 drivers there are regular dropouts in DSD mode when playing DSD64 / DSD128 using WASAPI exclusive DoP (with FiiO ASIO drivers everything is playing fine).

Limitations:
- FiiO Control app cannot store or read any settings from JM20 Max's hardware, including PCM-filter setting*.
(be warned, I did not try switching to UAC 1.0, and do not know the effect of switching. it could potentially break the device or simply have no effect.)
- Windows volume control has no effect in some cases when FiiO driver is used.
(in such case the volume can be changed from the driver's control panel.)

*PCM-filter switching does actually work but only if used on an Android device and only while jm20 max is connected to it. Once unplugged the setting is lost and the default "Min Phase Fast Roll-Off" filter will be used on the next connection to any device.

Here's how I use it:
- connect JM20 Max
- open Neutron app and allow it to access FiiO KA11 (the new name of JM20 Max)
- start the playback (not a must at his point, just a logical step)
- open FiiO Control app and allow the access as well
- change the filter settings (by default the NOS filter will be shown, simply ignore that, since the app cannot read the setting from the JM20 hardware and uses NOS as default value, while the actual setting on the device is still Min Phase Fast Roll-Off. Just tap on any filter and it will work as intended.)


+1

JM20 Max is a great device for the price, but I will go with FiiO KA11 or its successor next time because of the aforementioned features and arguably better durability.

Two things to note:

• As for the limitation of reconstruction filter setting not being stored, It has not been confirmed that FiiO Control app works properly with the actual KA11 hardware. I suspect that it may still not work as intended with the actual KA11.
• As for the durability, I prefer the JM20 MAX's design (i.e., its cable is for analog signal) to the KA11's (or the Shanling UA Mini). We see more frequent reports of KA11 failures than JM20 Max's.

 

[Agamemnon]

@jkim @o0o thanks for the information. can you kindly tell how to flash ka11 firmware? when i try to do that as i ve done before with ja11, ka11 firmware exe is saying usb device not found for jm20 max.


EDIT: Nevermind found correct vendor ids and flashed ka11 firmware. Thanks for letting know it was possible.

 

[Cleawave]

I wish the FiiO KA11 firmware could be applied to the JM20/JM30 (both without an amp chip) since they use the same bridge chip. (No courage to try)

Apparently, applying the FiiO KA11 firmware lets you disable the fade-in effect when starting playback in the Windows app. So maybe applying the firmware could fix the 0.5-second skip at the start of playback on the JM30... or maybe not.

 

[OK1]

I hope it's better than the 'standard' version I bought that failed after about a week and a half, giving me an 'Accessory drawing too much power' warning which cycled off and on about once per second. It was the third out of three dongles that failed on me, two of which I bought after enthusiastic reviews here, The hardwired cable on my Tanchjin Space Lite (not reveiwed) developed an intermittent in its hardwired cable so, toss. The cable on my TempoTec Sonata developed one also but at least that one had a user-replaceable USBC cable- but replacing it didn't fix the loud POP when plugging it into my phone, so I don't use it anymore. It has a little window with an LED so yuu can see part of the curcuitry though.

On the other hand, my '$9 phone dongle' (as it's referred to around here), has none of the above problems and just keeps working.

IEMs generally don't need the kind of power being discussed here but if someone has higher impedance cans or low impedance. low sensitivity 'phones, this night be a good choice.

After about 18 months, the USB-C to USB-C cable which came with a TempoTec Sonata BHD, also fails intermittently, Looks like it started when it got yanked from a smartphone which fell. As you have said, thankfully the cable is replaceable.

 

[OK1]

The DACs I have had or have:

HRT Music Streamer II+
Hidizs S9
Ugreen £12 dongle
Moondrop Click
RME ADI-2 DAC FS
JCally JM20 Max

The differences I heard:

The question can be posed, could this be due to weaknesses in other parts of the listening chain, especially the transducers, that make these differences inaudible?

I once believed that there should be no discernible difference between DAC's which perform better than a certain threshold.

I have not done any scientific testing or blind listening, but I think I can hear differences between supposedly decent DACs, especially when my listening device/setup improved. These are not night and day differences, but small changes in the sharpness or dullness of the end result. A hard thing to express when there are no measures for what one perceives and is trying to describe.

Spent about two hours listening and comparing a few dongle dacs today

1. TempoTec Sonata BHD (non Pro version) - Could be bias, or placebo. This obviously sounded best

2. A Samsung USB-C Dongle (could be a fake one cos I remember ordering this three times from three different stores, and none of them looked the same or registered the same name, when connected to Windows), and they clearly did not sound the same. One of them has audible high frequency noise!

3. A no name USB-C DAC from Ali-Express. I wanted something extremely portable - this one has no cable and is really small. Limited to 16 bit 48Khz, but that;'s ok, cos its not intended for any critical listening - Youtube, WhatsApp, casual Spotify, Social media, when I am away from a desk or out of the house. Costs less than £2. This came 2nd, and was the closest to the sound of the BHD. Now that was a huge surprise. Solves the problem of power limiting which I experience with the Apple dongle, when used with Android smartphones, and I have to turn up the volume on the smartphone (with Apple dongle). With this dongle, level set on the smartphone are similar to the other dongles.

https://www.aliexpress.com/item/1005009281207642.html

4. Apple Dongle - US version - seemed to have emphasis in the midrange, and rolled off at both ends of the audible frequency spectrum. Somewhat smoothed.

5. GraveAudio DA6 - a CX31993 based dongle - This - sounded veiled in the high frequencies, was the most comfortable to listen to, but there was a sense of detail missing. Just a bit veiled, like a dip in the high frequencies had been achieved via a tiny shelf EQ. Just a small shaving off of the transients.

None of this is scientific. And none of this can be proven, at least no yet. Maybe sometime in the future we may discover why some of us hear differences in DACs. Thinking aloud, could it be the slew rate in the headphone opamps?