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Topping DX3 Pro+ Review (DAC & Headphone Amp)

staticV3

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@SiegwardZwiebelbrudi Here's the most likely culprit based on your audio file:
Screenshot 2022-07-28 125017.png
These blips happen at regular intervals in your track and probably trigger the DX3Pro+'s DC protection.
 
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@SiegwardZwiebelbrudi Here's the most likely culprit based on your audio file:
View attachment 220922
These blips happen at regular intervals in your track and probably trigger the DX3Pro+'s DC protection.
wow, thats super interesting! SHOULD they trigger DC protection though or is this a bad implementation from Topping? I struggle to find a proper alternative at that price, any stack with the same power is at least a hundo more expensive
 

staticV3

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SHOULD they trigger DC protection though or is this a bad implementation from Topping?
Afaik this kind of signal has no reason to exist in music. If you find it, then the mixing/mastering engineer didn't do their job.
Whether the potential for damage is high enough to justify such a sensitive protection circuit, I don't know.
I struggle to find a proper alternative at that price, any stack with the same power is at least a hundo more expensive
Meizu HiFi + Topping L30 II is $15 less expensive than the DX3Pro+, but significantly more powerful.
No Bluetooth, display, S/PDIF input, or remote though. Also not sure what the DC protection is like on the L30 II.
Max Voltage before clipping (knee) vs Load.png Max Power before clipping (knee) vs Load (1).png Perceived Loudness Increase_ L30 II vs DX3Pro+ (clipping_ knee).png
 
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torcid

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This is what Topping service has to say about the constant HP ERR issues with the DX3 Pro+ ( Thanks for saving my headphones from burning i guess)

Hi,

Sorry for the delay getting back to you.

Based on the audio file you provided, we have conducted relevant tests. We detected that the bass of this song is so low that it triggers the protection of DX3 pro+, which is likely to burn the headphones if it is not protected.

DX3 pro+ is equipped with headphone protection circuit. When you listen to this song with headphones, please lower the volume.

Best Regards

With firmware update v1.23 they tweaked the overcurrent protection kicking in to fast. You can try it out with updating your firmware to the newest version.

"What's updated:
Fixed an issue where the built-in amp overload protection was too sensitive to prompt "HP ERR" under certain circumstances."


But overcurrent protection has it's reason. So they will not deactivate it...

Newest firmware is v1.25 from July.

I had the protection kicking in 3 times. 1 time while playing online multiplayer and 2 times while playing (the same) amateur smartphone video from ukraine with loud explosions in the background. But when i lowered the volume it didn't kick in anymore.
 
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With firmware update v1.23 they tweaked the overcurrent protection kicking in to fast. You can try it out with updating your firmware to the newest version.

"What's updated:
Fixed an issue where the built-in amp overload protection was too sensitive to prompt "HP ERR" under certain circumstances."


But overcurrent protection has it's reason. So they will not deactivate it...

Newest firmware is v1.25 from July.

I had the protection kicking in 3 times. 1 time while playing online multiplayer and 2 times while playing (the same) amateur smartphone video from ukraine with loud explosions in the background. But when i lowered the volume it didn't kick in anymore.
so it seems its an issue with low frequencies below 20hz, i applied a highpass filter 10hz Q 0.7 that resolved the issue.

obviously i am on the newest firmware, if you scroll up in this thread, you´ll notice i made a post when 1.25 was released XD
 

torcid

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so it seems its an issue with low frequencies below 20hz, i applied a highpass filter 10hz Q 0.7 that resolved the issue.

obviously i am on the newest firmware, if you scroll up in this thread, you´ll notice i made a post when 1.25 was released XD

The thread is 61 pages long! ;)

How do i know that you installed it? ;)

I had the overcurrent protection kicking in with v1.23
 
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The thread is 61 pages long! ;)

How do i know that you installed it? ;)

I had the overcurrent protection kicking in with v1.23
well, it really doesn´t matter, but my post was quite recent, so you might have noticed that as well as you noticed this...
as far as your issues, check out applying a high pass filter, some audioengineers don´t filter subsonic stuff out in the mix and this triggers dc protection
 

staticV3

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@rarewolf (2) is what you want. If that doesn't work, try the Apple USB2 CCK plus a regular printer cable (A male to B male), or the Apple USB3 CCK if you want to charge your iPhone while it's connected to the DX3
 

nsfgp

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if you choose method 2) it's extremely safe and there will be no disadvantage. it's called "impedance balanced" and many professional audio equipments are wired this way. it has all the nice properties balanced output has, such as common mode noise rejection, ground loop elimination, etc.
See the table in http://www.paformusic.org.uk/gl_b.htm#Balanced

The maximum output is 2V instead of 4V. if you don't listen at that high volume a lower voltage is even better.
This means even DX5 has 6 db higher dynamic range, because 4V is 6db hotter than 2V, DX3Pro+ has the same low absolute noise level as DX5.

The RCA to XLR connector is easy to do: connect RCA+ to XLR Pin 2, RCA ground to XLR Pin 1, and a 20Ohm resistor between XLR pin 1 and 3. Then you're all set.
The method works because the 20Ohm resistor is exactly what DX3 Pro+ has in its final output circuit.

Here's the wiring from google image search:
View attachment 195336

(please replace the 100 Ohm to 20Ohm)


See it in action:

View attachment 195337


If you want to apply this solution to another unbalanced product, you have to change the resistor value.
In some rare cases, you need to get the DAC output circuit and copy more passive components to Pin3 as well.
Fortunately for DX3Pro+ only a 20Ohm resistor is needed.


Conclusion: If you don't need full 4V output, just stay with your DX3 Pro+. It's trivial to make it balanced.
Don't purchase DX5 for its balanced output.
Folks I came across this older post from Audiofun and found it very interesting and educational. It seems this method can also be adapted to most if not all RCA/Unbalanced output from a device if you want to feed it into a balanced-input device. Of course voltage output of the unbalanced output will needs to be determined if sufficient for the input device in order to work well. The key is you need to know/determine the output impedance of the unbalanced output of the source device.
I then PM'ed Audiofun and asked a few followup questions. Just wanted to post our conversation here as below so everyone can see it. Hope you may find it useful.
I have not tried such conversion yet FYI.

----------------------------
Q: Would it works the same if I connect it as below? (which is simpler to do, R is the 20 ohm resistor)

1659048011247.png


Answer from Audiofun:
it works for eliminating the ground loop, but to avoid interference, you need to make sure the cable is very short.
alternative is to do a short dongle like this, and then connect to your speaker/amplifier using a long normal cable.
rule of thumb is, the closer 20ohm is to the device, the better.
---------------------------------
More Questions and Answers:
> One more question though. The 20 ohm value we use .. is it based on the Output impedance value of the DX3Pro+ published by Topping?? It is specified in Topping's manual/product listing BUT how do we know if it is accurate/true??

It's accurate. I measured it.

> Is it better/needed for us to measure the actual Output Impedance of our DAC and get the exact resistor value to use??
If so do you have instruction on how to measure output impedance of our DAC's RCA output??

a. You can do a tear down and find the circuit look like advertised:
https://nwzimg.wezhan.net/contents/sitefiles3604/18020413/images/4953000.jpg
the leftmost two resistors are marked with 30X, which means 20Ohm

b. You can do a tear down and measure the resistor using a multimeter. it's 20Ohm

c. You can avoid a teardown and connect output to a resistor A and then ground. Output a constant voltage. Let's say R_A = 100Ohm, and you measure the voltage it divides using a multimeter. Then change R_A to 200Ohm. Measure again. You'll get another voltage. Then you can calculate the internal resistor using simple math.

Shortcut: Let R_A = 20Ohm. You get voltage V1. Let R_A = infinity (don't connect a resistor), you get voltage V2. If V2 = 2V1, then You know internal resistor is equal to the first R_A (20Ohm).

d. You can avoid a teardown by just trusting me or Topping.
---------------------------------------------------------------------------
 

Ultor

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Hello :)

I have a Sundara, and I'm hesitating between this DX3 Pro+ and the Atom Plus stack.
I'll leave my previous stack (Modi MB + vali 2) in a closet, ha ha ha
 

rarewolf

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Hello :)

I have a Sundara, and I'm hesitating between this DX3 Pro+ and the Atom Plus stack.
I'll leave my previous stack (Modi MB + vali 2) in a closet, ha ha ha

Personally, I’m a bit miffed about Topping dropping the new versions of the E30/L30 DAC & Amp the same day I purchased the DX3Pro+…
 

rarewolf

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Actually, I’m somewhat happy the DX3P+ includes Bluetooth… which reminds me…

I listened to a reviewer imply the Bt antenna is for LDAC only… true?
 

Bleib

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Actually, I’m somewhat happy the DX3P+ includes Bluetooth… which reminds me…

I listened to a reviewer imply the Bt antenna is for LDAC only… true?
What, no. How could that be? It's for BT functionality
 

rarewolf

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But the combi it's more than double the price of the DX3Pro+ ;)

US$300 versus US$200. The pair was in my budget and had a few other features I’d like, but I think I’ll appreciate the convenience of having Bt in the end…
 

Bleib

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US$300 versus US$200. The pair was in my budget and had a few other features I’d like, but I think I’ll appreciate the convenience of having Bt in the end…
Plus it's nice to have digital control over the volume
 

Merkurio

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@JohnYang1997 Implementing hardware PEQ capabilities for future Topping models (using the QCC5171 for example) is part of the company’s roadmap?

Giving the astonishing value and performance/features of this single DX3 Pro+ box, adding it DSP capabilities a la Qudelix would be an absolute game changer and a huge market advantage for the first to do it properly (not counting RME).

I tell you this because FiiO is already thinking about the implementation in desktop products without the typical dongle size limitation, but you have the edge at engineering level, so you should take advantage of it. :)
 

rarewolf

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Plus it's nice to have digital control over the volume

I’m not sure I understand. According to the use of DAC/amp dongles (e.g., L&P W2), it’s always better to maximixe the digital volume at the source and adjust the listening volume at the amplifier, and that’s analog(?) Sure, it may be digital control, but we’re talking about the analog’s amplitude, correct?
 
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