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Review and Measurements of Topping DX3Pro DAC and Headphone Amp

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Aside from the phantom clicks, the only flaw in my book is the sole 3.5mm jack. Kind of wish they went the extra mile there, since it's so much easier to adapt to 6.35mm than vice versa.
I think I saw somewhere (probably here) that it was an issue of space. Not sure how big the PCB inside is in relation to the aluminum housing, but I'm guessing they would have had to make the whole unit larger or the screen smaller in order to accommodate 6.35mm jack. That's pretty much the only thing missing here in a premium product.
 

voon

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I have a problem with this device ;( I tested it with cheap phone IEMs (the 3.5mm TRRS jacks I think you call them .. for a microphone as well). It worked fine at usable volumes .. but suddenly one ear gets hot and the IEMs right channel dies. I tried with another cheap IEM .. same thing ... right channel dies. I cracked open the casings and used a voltage meter to see what's going on and I see around up to 0.5V on the working left channel, depending on music, volume etc it changes, but stays below around that. And the right channel shows nearly 5V! I'm no electronics guy at all, using a Fluke meter was already my limit.

The chinese seller says, Topping said "I should use the right headphones and mine are not hifi enough and don't have the right impendance". What? I don't buy that if it was playing happily before at a moderate volume knob setting, so nothing outrageous. Also I won't test this with a normal no-mic TRS headphone while the meter says 5V.

Could anyone tell me what's going on? I don't trust my dx3 pro anymore.
 
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amirm

amirm

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Thread Starter #944
I cracked open the casings and used a voltage meter to see what's going on and I see around up to 0.5V on the working left channel, depending on music, volume etc it changes, but stays below around that. And the right channel shows nearly 5V!
The winding has burned out on the one channel allowing the voltage to rise to maximum. So that is "normal."

Hard to predict what caused the one channel to die. Do you have any none-IEMs to try with it?
 

Davros

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just got dx3pro it is much ticking noise each sound played how to fix it ? Hope it is very expensive in my country
 

voon

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The winding has burned out on the one channel allowing the voltage to rise to maximum. So that is "normal."

Hard to predict what caused the one channel to die. Do you have any none-IEMs to try with it?
Thanks for your quick answer! I only had these two cheap phone IEMs ... I do have other IEMs like the UE TF10, which I had running on the dx3 at home, and that worked .. it also worked at work, the first one did not immediatly burn, that was all of a sudden after a minute or so of hearing music.

I do have a pair of Beyer Dynamic DT880 .. but I can't risk those for such a test.

I'm a bit stressed cause I bought the dx3 thinking it'd be a nice dac for my laptop .. it didn't say it doesn't work with IEMs ;( at least not in a language I understand.
 
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Everyone has heard your opinion. You have stated it many times. Topping is here, acknowledged their design decision and are working on another approach. Your comments are not helping accelerate a solution, or even identify why it happens more or less in some systems.
That's plainly not true, people can go back in the thread and see I helped pretty much identify the exact issue under what circumstance before Topping restated it, I also posted a temporary solution to stop it using Voicemeeter back on page 28. But fine, I'm really not that surprised you're glossing over salient facts again....
 
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Jimmy

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Maybe your unit is defective and has a large DC offset in one channel, try to measure it as is explained here (smaller values are tolerable, 5v is not):

http://www.rock-grotto.co.uk/dcoffset.htm

Maybe the DC servo circuitry is broken, since the amp doesn't seem to use output caps.

You can just cut the cable of your dead headphones for measurements, but if you have a 5v in one channel just send it for repair or it will kill sooner or later every headphones you plug in.

Thanks for your quick answer! I only had these two cheap phone IEMs ... I do have other IEMs like the UE TF10, which I had running on the dx3 at home, and that worked .. it also worked at work, the first one did not immediatly burn, that was all of a sudden after a minute or so of hearing music.

I do have a pair of Beyer Dynamic DT880 .. but I can't risk those for such a test.

I'm a bit stressed cause I bought the dx3 thinking it'd be a nice dac for my laptop .. it didn't say it doesn't work with IEMs ;( at least not in a language I understand.
 

Yuno

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That being said, I've been happening into a repeatable circumstance wherein the relay clicking completely stops during USB output and everything works with smooth, silent sailing from there on out. I haven't isolated the cause
The reason is that you are not using exclusive mode, and audio is being "held" by some application. If you open video on youtube, start playing it, then pause and leave it paused, clicking will stop. That's because clock is set for that youtube video playing in the background. If you close your browser, clicking will come back. It's pretty much the same reason why continuous playback doesn't produce clicking, there is no stop, so clock is not changed.
We have had a bunch of workarounds 20 pages ago or so, the best one is using optical as many people know by now. Voicemeeter one is acceptable for people without spdif output.

And as for negativity and whining, I agree that there is a lot of this in this thread and it's main reason why I stopped posting anything (plus the fact we have topping response anyway) but also if we did not start discussing clicking here and mass contact topping who knows if they would ever decide to produce any kind of fix on their own.
 

maty

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Maybe your unit is defective and has a large DC offset in one channel, try to measure it as is explained here (smaller values are tolerable, 5v is not).
Off topic

I have measured near 3 Vdc in my terrible electrical grid (50Hz/230Vac). I know, it is incredible but true.
 

voon

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Maybe your unit is defective and has a large DC offset in one channel, try to measure it as is explained here (smaller values are tolerable, 5v is not):

http://www.rock-grotto.co.uk/dcoffset.htm

Maybe the DC servo circuitry is broken, since the amp doesn't seem to use output caps.

You can just cut the cable of your dead headphones for measurements, but if you have a 5v in one channel just send it for repair or it will kill sooner or later every headphones you plug in.
Hm, I can't really get to the socket inside the unit ... the cable between front knob/display stops me from sliding out the board and I can't unscrew the front .. it's seems to be screwed to the unit from the iside by means of very long, thin allen keys entering from the back :/ I also tried to cut the cable and measure there on another IEM, but the cables are so utterly thin .. I'm not sure I'm really having access to the copper inside or if the strands are somehow laquer painted or whatever .. I could not read the voltage there .. I could at the sodler points of a broken driver .. that's where I measured the 5V.

Now I have conflicting info though ... Amir says it's normal to have 5V in one earbud due to a wasted driver and you're saying it's faulty in any case?

PS: Sending the unit back to china would cost me 50ish USD ... argh
 

Jimmy

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Audio is AC, not DC, a small DC component in the signal is acceptable, but 5v=5000mv which is hundreds of times what's tolerable, and the symptoms are exactly what you described, coil overheating and subsequent damage.

If you aren't able to use the dead iem's cable for measurement, you can just buy a male 3.5 headphone plug unscrew the cover and make the measurement at the connectors.

If you received a defective product I would consider it a DOA (dead on arrival), the vendor should take care of everything, not you, if you bought through ebay or AliExpress use them to mediate.


Hm, I can't really get to the socket inside the unit ... the cable between front knob/display stops me from sliding out the board and I can't unscrew the front .. it's seems to be screwed to the unit from the iside by means of very long, thin allen keys entering from the back :/ I also tried to cut the cable and measure there on another IEM, but the cables are so utterly thin .. I'm not sure I'm really having access to the copper inside or if the strands are somehow laquer painted or whatever .. I could not read the voltage there .. I could at the sodler points of a broken driver .. that's where I measured the 5V.

Now I have conflicting info though ... Amir says it's normal to have 5V in one earbud due to a wasted driver and you're saying it's faulty in any case?

PS: Sending the unit back to china would cost me 50ish USD ... argh
 
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Hm, I can't really get to the socket inside the unit ... the cable between front knob/display stops me from sliding out the board and I can't unscrew the front .. it's seems to be screwed to the unit from the iside by means of very long, thin allen keys entering from the back :/ I also tried to cut the cable and measure there on another IEM, but the cables are so utterly thin .. I'm not sure I'm really having access to the copper inside or if the strands are somehow laquer painted or whatever .. I could not read the voltage there .. I could at the sodler points of a broken driver .. that's where I measured the 5V.

Now I have conflicting info though ... Amir says it's normal to have 5V in one earbud due to a wasted driver and you're saying it's faulty in any case?

PS: Sending the unit back to china would cost me 50ish USD ... argh
If you have UE TF10's can you not detach the cable and measure the plug?
 
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PS: Sending the unit back to china would cost me 50ish USD ... argh
Sorry I don't have any technical advice to offer. But if you can find a way to ship it back for a bit less, PayPal will cover the return shipping up to $30 USD if you used them to pay. (max 12 times a year)
 

derp1n

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The winding has burned out on the one channel allowing the voltage to rise to maximum. So that is "normal."

Hard to predict what caused the one channel to die. Do you have any none-IEMs to try with it?
:oops: It's not normal for it to immediately happen to two previously working earbuds.
 

Veri

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Mine just arrived. There's more clarity than my laptop's embedded cirrus logic at least :D sound is GOOD.

I'm using OSX on my work computer and there's no clicking noise besides the first initial one. Windows problem?

And god I'm really running out of desk space. sorry for the clutter
t.jpg
 
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