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

[LDvo]

Can you check it again? With the Android app V2.2.6, the inconsistency between two app types has been resolved.

Sure. As i've mentioned - i tested it with latest App ver and firmware.
I will do it again after restarting the phone, clear app cache and provide screenshots to illustrate it.
And instead of using button Disconnect, i will physically disconnect and connect the device.

 

[LDvo]

Sure. As i've mentioned - i tested it with latest App ver and firmware.
I will do it again after restarting the phone, clear app cache and provide screenshots to illustrate it.
And instead of using button Disconnect, i will physically disconnect and connect the device.

Don't even need to compare Web site with Phone App - even Web site does not save the changes.
If i change DAC mode only and physically re-connect - looks like it remembers my changes
if i change Gain mode only and physically re-connect - it always switched to high gain
if i change both DAC and Gain modes and physically re-connect - it remembers my DAC change and does not remember Gain change (goes to high)
And Webpage RESET button didn't change anything on that page even after physically re-connect - same filter and same setting remained.

 

[jkim]

Below is a list of issues with TRN Black Pearl that I found after the recent firmware and app updates were applied:

1. EQ Effect apply to device: There is an issue with the web app applying an EQ setting (either a default or custom setting) to the device. An EQ setting chosen in the web app is not saved to the device even after clicking on the “apply” button, and cannot be read by the Android app.
2. EQ Effect shelving filters: The Low- and High-shelf filters still apply double the gain set in the app---I tested the web app. For example, if I the Gain is set to +4 dB for a Highshelf filter, the app actually applies +8 dB.
3. DAC Filter module: Either the Android or the web app does NOT remember the “Low” output gain mode. After the device is physically reconnected, it always reverts back to “High” gain.
4. EQ Effect Highpass and Lowpass filters: These work correctly in actual measurements; however, the EQ curve shown on the app (I tested the web app) does not reflect a Q parameter value. That is, the filters work correctly as set by the user, but the user will not see the precise effect of a chosen Q value on the EQ curve graph.

I sent this list to the WalkPlay team. Let's see how quickly they will react. They have been very responsive so far.

Please let me know if any of you find other issues.

 

[LDvo]

Below is a list of issues with TRN Black Pearl that I found after the recent firmware and app updates are applied:

1. EQ Effect apply to device: There is an issue with the web app applying an EQ setting (either a default or custom setting) to the device. An EQ setting chosen in the web app is not saved to the device even after clicking on the “apply” button, and cannot be read by the Android app.
2. EQ Effect shelving filters: The Low- and High-shelf filters still apply double the gain set in the app---I tested the web app. For example, if I the Gain is set to +4 dB for a Highshelf filter, the app actually applies +8 dB.
3. DAC Filter module: Either the Android or the web app does NOT remember the “Low” output gain mode. After the device is physically reconnected, it always reverts back to “High” gain.
4. EQ Effect Highpass and Lowpass filters: These work correctly in actual measurements; however, the EQ curve shown on the app (I tested the web app) does not reflect a Q parameter value. That is, the filters work correctly as set by the user, but the user will not see the precise effect of a chosen Q value on the EQ curve graph.

I sent this list to the WalkPlay team. Let's see how quickly they will react. They have been very responsive so far.

Please let me know if any of you find other issues.

Web UI - There is no Vertical scrolling control on EQ Effect Page \ Online (maybe on other tabs as well - nothing yet to scroll for now)

 

[jkim]

Web UI - There is no Vertical scrolling control on EQ Effect Page \ Online (maybe on other tabs as well - nothing yet to scroll for now)

I don't get this. Would you be more specific?

 

[LDvo]

I don't get this. Would you be more specific?

Yes, sure, minor but annoying UI thing - see on the right highlighted - missing way to scroll vertically thru different published preset items
(PgDn/PgUp works, but cannot use mouse):

 

[jkim]

Yes, sure, minor but annoying UI thing - see on the right highlighted - missing way to scroll vertically thru different published preset items
(PgDn/PgUp works, but cannot use mouse):



View attachment 470334

What browser are you using? In my case with Chrome on Windows 11, I can scroll using my mouse wheel by putting its cursor on that part. Up/down arrow or PgUp/PgDn keys work, too. A scroll bar would be nice, though.

 

[LDvo]

What browser are you using? In my case with Chrome on Windows 11, I can scroll using my mouse wheel by putting its cursor on that part. Up/down arrow or PgUp/PgDn keys work, too. A scroll bar would be nice, though.

I use standard Edge with touchpad (Chromium engine i guess) - yes, scroll bar is missing, i think.
Looks like this Web app is missing basic QA testing in general.

 

[jkim]

Important Update (8/16/25)

WalkPlay/TTGK is another company reacting to the issue of DRE-induced distortion associated with the CS431xx chips! A new firmware release (V0.3) for the TRN Black Pearl changed a key parameter related to DRE operation. With this firmware installed, the Black Pearl does not exhibit audible distortion behavior caused by DRE while retaining reconstruction filter options. An analysis based on measurements was added to the bottom of the original review.

 

[Fullwonder]

Hello, I got this dac as an upgrade from cx31993 there is no more noise like before with my Artti T10 and it sounds really good. But I have weird problems like using the buttons on the dac can lead to disconnection or high screeching sound and it's random. also in order to change the headphone or reconnect it seems that I must wait for a few seconds before inserting another headphone or connecting the dac itself to another/same device or it will not work (light indicator won't turn on)

I'm using version 0.3

 

[jkim]

using the buttons on the dac can lead to disconnection or high screeching sound and it's random.

Welcome to ASR! Would you be more specific on this issue? What kind of button usage? Although you said it's random, how can we most likely replicate this problem?

 

[swa2023]

Great review. Could you please show the 32-tone level sweep with 0dBFS referenced to 50mV? I want to know "Cirrus Hump" distortion at low output level.

 

[jkim]

Great review. Could you please show the 32-tone level sweep with 0dBFS referenced to 50mV? I want to know "Cirrus Hump" distortion at low output level.

I am not sure what you mean by "0 dBFS referenced to 50 mV". You mean the hardware volume control set to near 50 mV for the input signal at 0 dBFS? It does not matter whether you lower the volume with hardware buttons or software processing---both methods are digital volume adjustment. All the information about the device's distortion behavior versus signal level is there in my review.

 

[HissingFree]

Great review. Could you please show the 32-tone level sweep with 0dBFS referenced to 50mV? I want to know "Cirrus Hump" distortion at low output level.

I think you would be looking at around -30dBFS if you want to know distortion at 50mV.

 

[jkim]

[8/19/2025] New Firmware

A firmware update (V0.4) has been released, which fixes:

• Gain applied to high- and low-shelf filters
• Output gain mode (low/high) in the DAC Filter module
• EQ Curve plotting for high- and low-pass filters

 

[zany.ninja]

Is currently on sale for $32.55 (!) at Shenzhen Audio. Just fyi.

(That's the price displayed to me in the EU - not sure if it's the same price for the US).

 

[LDvo]

Is currently on sale for $32.55 (!) at Shenzhen Audio. Just fyi.

(That's the price displayed to me in the EU - not sure if it's the same price for the US).

Also same excelent price now on Amzn

 

[LDvo]

[8/19/2025] New Firmware

A firmware update (V0.4) has been released, which fixes:

• Gain applied to high- and low-shelf filters
• Output gain mode (low/high) in the DAC Filter module
• EQ Curve plotting for high- and low-pass filters

Thanks for fast turn around. I have to try

 

[jkim]

Again, below is a list of issues with TRN Black Pearl that I found (or remain) after the recent firmware (V0.4) and app updates were applied:

1. EQ Effect apply to device: There is an issue with the web app applying an EQ setting (either a default or custom setting) to the device. An EQ setting chosen in the web app is not saved to the device even after clicking on the “apply” button, and cannot be read by the Android app.—pending
2. EQ Effect shelving filters: The Low-shelf filter’s Q factor shows a correct effect on the EQ Curve but actually applies a wrong Q value. Specifically, it seems to interpret user’s Q factor input as a “shelf slope” or S parameter. For example, to have an effect of Q = 0.707, the user have to enter Q = 1.0. Note that the Q factor has a clear, technical definition. It should not be mistaken as the S parameter. The High-shelf filter has the same problem, except that the Q factor’s effect is wrong even on the EQ Curve on the app.—needs to be solved
3. EQ Effect Gain: This is not an issue but a suggestion. Currently, the range of a Peak or a Shelf filter’s gain adjustment is -10 to +10 dB. This is generally too narrow. I suggest increasing the range to either -12 to +12 dB or -15 to +15 dB.—suggested

I sent this list to the WalkPlay team. Let's see how quickly they will react this time.

EDIT. To avoid confusion, note that the first issue is not a big problem since the app has no problem retrieving an EQ preset selected previously within each app type. The issue is only when the Android app tries to read a preset applied by the web app.

 

[KDRN]

Again, below is a list of issues with TRN Black Pearl that I found (or remain) after the recent firmware (V0.4) and app updates were applied:

1. EQ Effect apply to device: There is an issue with the web app applying an EQ setting (either a default or custom setting) to the device. An EQ setting chosen in the web app is not saved to the device even after clicking on the “apply” button, and cannot be read by the Android app.—pending
2. EQ Effect shelving filters: The Low-shelf filter’s Q factor shows a correct effect on the EQ Curve but actually applies a wrong Q value. Specifically, it seems to interpret user’s Q factor input as a “shelf slope” or S parameter. For example, to have an effect of Q = 0.707, the user have to enter Q = 1.0. Note that the Q factor has a clear, technical definition. It should not be mistaken as the S parameter. The High-shelf filter has the same problem, except that the Q factor’s effect is wrong even on the EQ Curve on the app.—needs to be solved
3. EQ Effect Gain: This is not an issue but a suggestion. Currently, the range of a Peak or a Shelf filter’s gain adjustment is -10 to +10 dB. This is generally too narrow. I suggest increasing the range to either -12 to +12 dB or -15 to +15 dB.—suggested

I sent this list to the WalkPlay team. Let's see how quickly they will react this time.

EDIT. To avoid confusion, note that the first issue is not a big problem since the app has no problem retrieving an EQ preset selected previously within each app type. The issue is only when the Android app tries to read a preset applied by the web app.

are they considering to add a DRE switch in the future?

i wonder if walkplay apply the same fixes in other brand's dac with the same module. and maybe their future cirrus logic modules too, like the

TT39518F01-PROMAX​