Review of TRN Black Pearl: Portable USB DAC & Headphone Amp with 10-band PEQ

[TommyT]

Hi jkim,
Thank you for the excellent and detailed review! I have a quick question about the balanced output power of the Black Pearl.
The official specs list 320 mW @ 32 ohms, but your measurement shows 190.7 mW @ 32 ohms at THD+N < 0.001%. Could you please clarify the difference between these two figures? Is the 320 mW rating likely measured at a higher distortion level (e.g., 1% THD) or under single-channel drive conditions?

 

[KDRN]

ported the driver to android. it is "functionally complete"

View attachment 531031View attachment 531032

released the source code and apks

still very unstable. it is causing system crashed or hard reboots. im having trouble finding out since it doesnt show proper logs and i heard if a system hardreset/reboot happens is due to a kernel panic. but i cant access the logs of the kernel since i need root access. i managed to reduce the amount of times it hard reset/reboot. but it isnt fully gone.

source: https://github.com/cheesyserg/BlackPearlControl-Android


in other things, i discovered both the web driver and app isnt working as intended (possibly maintenance?)

if it was maintenance or any downtime. it shows how fragile the structure of walkplay. if they decided to not keep the website alive. we would loose access to the settings of every walkplay device

 

[Dracula99]

Hi everyone. I'm having a problem using this DAC/Amp on my smartphone. The left and right channels sometimes swap when I pause, exit the app, turn off the screen, or if I switch to the next track. On my PC, everything works fine. Could you please tell me how to fix this? I'd be grateful. My device ate an Xiaomi POCO F6 (Android 16). TRN Black Pearl firmware version - v0.5

 

[Insomniac-55]

I just purchased one of these and received it with the v0.6 firmware.

Unfortunately, despite reading that the DRE issue should be fixed I've found that it is quite audible using sensitive IEMs (Truthear Pure). The Dune test file has very audible crackling towards the end, and I also notice it for a fraction of a second before and after noises surrounded by silence (notification sounds, or when skipping songs).

I'm pretty sure it's the DRE distortion I'm hearing as it matches the descriptions earlier in the thread. It's a bit unfortunate as for my use (low power) it's effectively worse than the Apple dongle in practice, even though it measures better.

Is anyone else able to confirm this matches their experience, and it's not just something being broken in v0.6?

 

[ddmareo]

I just purchased one of these and received it with the v0.6 firmware.

Unfortunately, despite reading that the DRE issue should be fixed I've found that it is quite audible using sensitive IEMs (Truthear Pure). The Dune test file has very audible crackling towards the end, and I also notice it for a fraction of a second before and after noises surrounded by silence (notification sounds, or when skipping songs).

I'm pretty sure it's the DRE distortion I'm hearing as it matches the descriptions earlier in the thread. It's a bit unfortunate as for my use (low power) it's effectively worse than the Apple dongle in practice, even though it measures better.

Is anyone else able to confirm this matches their experience, and it's not just something being broken in v0.6?

i have the older batch of TRN Black Pearl and only got firmware version 0.5 as the latest. i have not noticed any crackling noise whatsoever even when using sensitive IEM like CCA CRA. it should have something to do with be the firmware the DAC is using on newer batches, or it could also be device and configuration that you’re plugging your DAC on

 

[Insomniac-55]

i have the older batch of TRN Black Pearl and only got firmware version 0.5 as the latest. i have not noticed any crackling noise whatsoever even when using sensitive IEM like CCA CRA. it should have something to do with be the firmware the DAC is using on newer batches, or it could also be device and configuration that you’re plugging your DAC on

That's interesting.

On mine I can hear the crackle on both my phone and computer, and regardless of which UAC mode it's in.

Setting it to NOS mode makes it stop, which also sounds similar to the original DRE problem. I might see if I can capture a spectrogram of the noise to see whether it looks the same (I've never had a chance to hear the original firmware).

EDIT:

Alright, I did a little bit of testing. I was unable to capture the clicks I'm able to hear (just piping the output into my motherboard's line-in, so it's not exactly surprising). However, did go back and listen to some sample clips from the earlier firmware with known DRE artefacts.

In those clips, I can hear clicks and pops during the louder parts of the sample files (such as during the start of the Dune sample clip). The clicks I hear with my unit are similar, but do not occur during the loud bits of the file. I only hear them at the end when the volume tails off to nothing. On the C-maj sample clip in the first post, I hear the clicks between the swells of volume.

Interestingly, in the OP jkim noted 'Again, if you zoom in, you can see very light vertical lines during transition. But I still couldn't hear these effects.' on the 'fixed' firmware - these are the exact regions where I'm able to hear the clicks. So it seems like what I'm hearing are indeed DRE artefacts, and my unit is probably behaving similarly to everyone else's - I'm just able to hear them for some reason, either because of my setup or the v0.6 firmware exacerbating the clicks.

Unfortunately it's also noticeable in real-world listening. For example, at the beginning of this track I can hear a burst of clicks in the silent gaps of the guitar intro. It's not horrible, but a bit dissapointing given I mainly wanted to use this DAC with IEMs in low-gain mode.

 

[CedarX]

It's not horrible, but a bit dissapointing given I mainly wanted to use this DAC with IEMs in low-gain mode.

Have you tried in high-gain mode and lower volume?

 

[Insomniac-55]

Have you tried in high-gain mode and lower volume?

Yeah, and all combinations of EQ on and off and the various output filters.

The clicking is always present at low volumes with the exception of NOS mode. Even the previous statement I made about the 'C-Maj' test audio isn't completely true - at low volumes I can hear crackling throughout the clip. It's only at higher volumes that the tone becomes clean until it fades in / out.

I also tried with my TIN T2s (slightly lower sensitivity IEMs) and can still hear the crackle.

By comparison, my Apple dongle is totally clean to my ears.

 

[carlcamper]

I just purchased one of these and received it with the v0.6 firmware.

Unfortunately, despite reading that the DRE issue should be fixed I've found that it is quite audible using sensitive IEMs (Truthear Pure). The Dune test file has very audible crackling towards the end, and I also notice it for a fraction of a second before and after noises surrounded by silence (notification sounds, or when skipping songs).

I'm pretty sure it's the DRE distortion I'm hearing as it matches the descriptions earlier in the thread. It's a bit unfortunate as for my use (low power) it's effectively worse than the Apple dongle in practice, even though it measures better.

Is anyone else able to confirm this matches their experience, and it's not just something being broken in v0.6?

I can also hear it and Im on v05. Thats why I hope they add a DRE disable option like my Snowsky Melody

 

[KDRN]

i have successfully dumped the firmware of the trn black pearl. and in the process of reverse engineering(and hopefully include a DRE Switch:3)


also my finding found that the firmware showed the actual manufacturer of the USB bridge chip.

its a SPACETOUCH chip. but im not sure if it is a spv4040.

 

[CedarX]

its a SPACETOUCH chip. but im not sure if it is a spv4040.

Spacetouch chip… or CBHT Audio chip (TTGK / WalkPlay), which are custom versions of Spacetouch chips—most likely derived from the SPV4040.

 

[KDRN]

i have successfully dumped the firmware of the trn black pearl. and in the process of reverse engineering(and hopefully include a DRE Switch:3)


also my finding found that the firmware showed the actual manufacturer of the USB bridge chip.

its a SPACETOUCH chip. but im not sure if it is a spv4040.

View attachment 535382

UPDATE: I (PROSUMED) to have found the DRE registers and apon testing between the digital filters with the disabled DRE(I think) modification and without the modification using the cmaj test. i can say the DRE distortion has been eliminated.

EDIT: false alarm. i was just setting every filter into NOS... anyone here with experience with reverse engineering. maybe send a message so i could send you the firmware file

EDIT2: leaving firmware file and flashing tool just in case https://drive.google.com/file/d/1-OiNrQgPjxL5G3tqXEm65w3IV58aPwr5/view?usp=sharing

 

[Insomniac-55]

UPDATE: I (PROSUMED) to have found the DRE registers and apon testing between the digital filters with the disabled DRE(I think) modification and without the modification using the cmaj test. i can say the DRE distortion has been eliminated.

EDIT: false alarm. i was just setting every filter into NOS... anyone here with experience with reverse engineering. maybe send a message so i could send you the firmware file

EDIT2: leaving firmware file and flashing tool just in case https://drive.google.com/file/d/1-OiNrQgPjxL5G3tqXEm65w3IV58aPwr5/view?usp=sharing

Pretty cool to see you giving this a crack. It's a bit beyond my skill level, but I'll be keeping an eye out for any breakthroughs you have!

 

[Nachmanowicz]

If I hook it to a computer, do you think a Black Pearl can properly drive a Sundara? I only have it's original cable, not the balanced one. Might buy balanced in the future if there's a clear advantage to it....

 

[mangaTom]

I just purchased one of these and received it with the v0.6 firmware.

Unfortunately, despite reading that the DRE issue should be fixed I've found that it is quite audible using sensitive IEMs (Truthear Pure). The Dune test file has very audible crackling towards the end, and I also notice it for a fraction of a second before and after noises surrounded by silence (notification sounds, or when skipping songs).

I'm pretty sure it's the DRE distortion I'm hearing as it matches the descriptions earlier in the thread. It's a bit unfortunate as for my use (low power) it's effectively worse than the Apple dongle in practice, even though it measures better.

Is anyone else able to confirm this matches their experience, and it's not just something being broken in v0.6?

I've been playing the Dune test file a few times and can't hear any clicks(aside from the one when the audio ends). I'm using a tanchjim bunny for this.

 

[Insomniac-55]

I've been playing the Dune test file a few times and can't hear any clicks(aside from the one when the audio ends). I'm using a tanchjim bunny for this.

Do you definitely have a reconstruction filter turned on (i.e. not in NOS mode)?

 

[mangaTom]

Do you definitely have a reconstruction filter turned on (i.e. not in NOS mode)?

Not really sure but I checked on the webapp but it's on fast ll filter,class H mode and output gain set to low.

 

[Insomniac-55]

Not really sure but I checked on the webapp but it's on fast ll filter,class H mode and output gain set to low.

That's pretty interesting. It's definitely audible on mine (mainly as the volume tails off at the end of the clip), and my settings are basically the same - only I'm using Class AB. I just tried in Class H mode and can still hear it.

Note that on the Dune file, it's only really obvious to me after the 8-10 second mark. The earlier, louder part of the file sounds clean.

I suspect you're not hearing it because your volume is set higher than mine - try listening to the clip (in a very quiet room) with the volume at say, half of your normal, comfortable volume.

 

[Mandy007]

New Web Based control app for DACs with PEQ

It's an open source project that looks to be vibe coded using AI, but it works fine on a few my USB DACs like the Black Pearl and Fiio JA11. I find it easier to use than the original manufacturers apps plus there is no need for registration. If your DAC uses WalkPlay it will work with this app...

www.audiosciencereview.com

Try this with your dac

 

[Mandy007]

re-reverse-engineered the black pearl's driver to windows written in python, gotten most of it working. theres no PEQ yet though. i may or may not include it. idk, gonatake a while for me to figure out

source: https://github.com/cheesyserg/pyBlackPearl

View attachment 530288

edit: Big ui Improvements and added PEQ
View attachment 530328

PEQ Page
View attachment 530327

New Web Based control app for DACs with PEQ

It's an open source project that looks to be vibe coded using AI, but it works fine on a few my USB DACs like the Black Pearl and Fiio JA11. I find it easier to use than the original manufacturers apps plus there is no need for registration. If your DAC uses WalkPlay it will work with this app...

www.audiosciencereview.com