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Review and Measurements of Topping DX3Pro DAC and Headphone Amp

JohnYang1997

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Zout.PNG
Measured with 8ohm load and no load. 0.1-0.2db difference. I took 2% difference. So 2% * 8ohm is 0.16ohm across the board. Really nice and consistent.
Edit: no i read it wrong. It's lower than 0.1db So 0.1ohm and less.
As the chip topology it's delta-sigma so basically it has to over sampling to a very high frequency. Idk the frequency exactly but you can get hint from the oscillator. I'm not an expert in that regard so I'll leave it as is.
 

JohnYang1997

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Hi, did you end up trying a 25Vdc external power supply?
The output of regular is fixed. Using high voltage makes not difference.
And I saw in the notification maybe you have changed, that power bank will eliminate ground related noise. Actually the smps are double insulated so already no ground noise to pass through. Sure you may try it may still function well. You just won't see improvement.
 

JohnYang1997

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But SMPS's can be sources of AC leakage current? A battery will not?
SMPS runs at very high frequency so not a problem. In fact, power bank also has smps in side to make sure the voltage is constant.
There may be some leakage but not an actual concern if the design was complied to safety standard as far as I know.
 

noel_fs

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Hi, does anyone know how DSD is handled with the headphone output of the DX3 Pro, with digital volume control?

Is DSD converted to PCM?

Maybe you know @amirm or if you have a Topping contact, can they clarify?
I dont know it for a fact, but im quite sure it just does pcm conversion and volume goes from there.
 

Music1969

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SMPS runs at very high frequency so not a problem.
RME just touched on this today:

"There is one weak point, though: the SMPS (power supply). It does not provide full isolation against ground loop noises, even produces its own (leakage current)."

As I mentioned, while battery powerbanks have switching regulators, they do eliminate this 'weak point' of SMPS's that RME discusses - full isolation against ground loops and no leakage currents...

https://www.audiosciencereview.com/...-adi-2-dac-and-headphone-amp.7546/post-198553

A lot of Pro Audio DACs have 12Vdc inputs and sometimes engineers use car batteries to power them, for this reason (immunity to AC related issues).
 
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I am very tempted by the prime day discount, but I am fearing for the issues discussed here and finally I think that I maybe better served by a portable amp like the NX4 DSD or the Xduoo XD-05.
 
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I just experienced the random shutdown that many of you have had with the DX3 Pro.
It just happened while I was playing music. I had to switch on the device by pressing the knob once and DX3 continued from where it was when it had switched off.

I didn't see that coming as I have had the unit nearly 3 weeks now and has received hundreds of hours of playtime already Untill now I haven't had the slightest problem.

Fingers crossed it won't happen again but I would lie if I claimed I'm not worried...
 

Wolven

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I just experienced the random shutdown that many of you have had with the DX3 Pro.
It just happened while I was playing music. I had to switch on the device by pressing the knob once and DX3 continued from where it was when it had switched off.

I didn't see that coming as I have had the unit nearly 3 weeks now and has received hundreds of hours of playtime already Untill now I haven't had the slightest problem.

Fingers crossed it won't happen again but I would lie if I claimed I'm not worried...
Yes, it is completely random. You can expect the shutdowns every 2-3 weeks.
My first unit did it, and the tested replacement unit does it too.
I worried about it too, but now I'm just chalking it up to live and learn. Odds, are it will be fine until the warranty expires.
 
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Yes, it is completely random. You can expect the shutdowns every 2-3 weeks.
My first unit did it, and the tested replacement unit does it too.
I worried about it too, but now I'm just chalking it up to live and learn. Odds, are it will be fine until the warranty expires.
If it does it every 3 weeks or, say, once a month, I'm totally fine. I hope it just won't get any more frequent or any worse down the line.

I know some have already replaced the PSU with a Mean Well brick and continued having the occasional drops but to my restricted knowledge, these switch offs probably are having to do with momentary voltage drops or spikes that a better PSU will potentially be able to address or even eliminate.

If that's the case, the automatic on/off relay of the unit is susceptible to voltage variation curves.
I have measured the voltage of the stock PSU with my multimeter and it reads substantially higher that the nominal 15V - 15.21 which is of course within range but at the higher end of the tolerance limits Taking into account that it is a cheap SMPS which barely outputs 1A, it does not particularity ooze quality (very lightweight and cheap plastics) or is worth of any trust. It's similar to one I have for powering a series of infra red lights for my security cameras.

At such low rated amperage capacity I'd bet the voltage drops can be a regular case, especially when the unit consumes current close to the PSU real capacitance.

That's the most reasonable theory I can think of.

I just ordered a Mean Well PSU which is substantially more powerful (rated at 1.66A) and hopefully it will also have a better voltage stabilization circuitry and overall power handling.
 

Wolven

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If it does it every 3 weeks or, say, once a month, I'm totally fine. I hope it just won't get any more frequent or any worse down the line.

I know some have already replaced the PSU with a Mean Well brick and continued having the occasional drops but to my restricted knowledge, these switch offs probably are having to do with momentary voltage drops or spikes that a better PSU will potentially be able to address or even eliminate.

If that's the case, the automatic on/off relay of the unit is susceptible to voltage variation curves.
I have measured the voltage of the stock PSU with my multimeter and it reads substantially higher that the nominal 15V - 15.21 which is of course within range but at the higher end of the tolerance limits Taking into account that it is a cheap SMPS which barely outputs 1A, it does not particularity ooze quality (very lightweight and cheap plastics) or is worth of any trust. It's similar to one I have for powering a series of infra red lights for my security cameras.

At such low rated amperage capacity I'd bet the voltage drops can be a regular case, especially when the unit consumes current close to the PSU real capacitance.

That's the most reasonable theory I can think of.

I just ordered a Mean Well PSU which is substantially more powerful (rated at 1.66A) and hopefully it will also have a better voltage stabilization circuitry and overall power handling.
Let us know how it goes. If it works for you I may replace it too, although like you said some people have replaced it and still are having issues. I'm going to just live with it for now.
 

Toku

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I used 2 DX3 Pros for 8 months with a UBS connection to a Windows 10 PC. And I experienced Self sleep many times. The trouble was reported to this forum. S / N of two DX3ro is 1808 -----.
However, since this symptom does not occur when OPT and Coax are connected, it is considered that the cause is a problem with the USB setting of PC, and if "USB selective suspend 'setting" of Windows 10 is set to Disable, it will be normal for two months thereafter.

USB selective suspend is normally set to "Enable" in windows 10.
But I really have to wait a little longer to see if this is really the cause. The power supply uses the accessories of the product.
Windows 10 has used Ver 1809 and Ver 1903.

Please search the Web for the contents of "USB selective suspend 'setting".

https://www.windowscentral.com/how-prevent-windows-10-turning-usb-devices
https://www.groovypost.com/howto/usb-selective-suspend-windows-explained/
 
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