Review and Measurements of Topping DX3Pro DAC and Headphone Amp

[aka_Z]

Looks like that is not well protected against interference . Motherboard should be, it's in the metal/aluminium case after all. Except display part and volume control. Maybe problem is coming trough power supply. I bought ferrite core (SF-130), made couple of loops of power cable and then close the core around, didn't help. Tried the same with audio cable coming from DX3Pro to power monitors, didn't help. Anyway, you can give a try, it costs around $4.

 

[gypsygib]

I have experienced some interference with my power monitors and have traced it to DX3pro too, it comes and goes. I don't know why it has started to happen. Basically, it sounds like interference of the kind you would get if you put a phone or antenna next to an unshielded speaker.
This thing is an antenna of sorts, (non scientific description).

Try headphones on high gain, you may hear it as well in one of the channels.

 

[david99]

This is what I received from Topping support regarding issues with DX3 Pro after exchange of few email in last month:

Dear David



Sure. Now we lock the problem is in OPA2140. For defect units, when we replace the OPA2140, it works fine even after 100+ hour aging test.



Best Regards!

----------------------------------

TOPPING service

 

[Pavel]

The headphone amplifier in the Aune T1 is made in a similar way to the DX3. But it uses NE5532. And the sound is much better than the DX3.
I prefer to listen to the DX3 line output -> Aune T1 amplifier (tube removed) -> Grado SR1E (32 ohm)

 

[antero]

I've noticed that this unit has been put up back on amazon.de by shenzenaudio and it's back in stock on audiophonics.fr as well. Is it safe to assume that these are the new, revised units?

 

[nirschl]

Well, fingers crossed but, I have been using this unit since December with no real issues. other than working the remote and realizing there is an order to connect an iOS device to it. I'm using an iPhone X and a camera connection kit to USB and HD600's. Yamaha monitors for the iMac via RCA line out. Listening to Eric Bibb - A Selection of Analogue Bibb as I type. Plenty of power and superb clarity.

My question for those with more experience than me...how do I get it(or even the D10) to recognize DSD instead of PCM? Using Onkyo HD Player via iPhone X with several DSD 5.6Mhz/ PCM 192khz files. When connected and playing it immediately goes to PCM. And when I switch to "Real Time DSD Conversion" in the app the sound stops. Any ideas here?

 

[david99]

I've noticed that this unit has been put up back on amazon.de by shenzenaudio and it's back in stock on audiophonics.fr as well. Is it safe to assume that these are the new, revised units?

I wrote to audiophonics some week ago an they have 1901 on stock so those are definitely not revised ones, if there are even some revised ones. According to response from Topping they didn't changed nothing in new batches they are just heavily testing them 100+ hours.

 

[Veri]

I wrote to audiophonics some week ago an they have 1901 on stock so those are definitely not revised ones, if there are even some revised ones. According to response from Topping they didn't changed nothing in new batches they are just heavily testing them 100+ hours.

Wait then how about that OPA2140?

 

[antero]

I wrote to audiophonics some week ago an they have 1901 on stock so those are definitely not revised ones, if there are even some revised ones. According to response from Topping they didn't changed nothing in new batches they are just heavily testing them 100+ hours.

They weren't in stock until a week or so ago though. I'd like to not deal with returning if the unit breaks which is unfortunate since this unit has everything I would want.

 

[david99]

Wait then how about that OPA2140?

I asked if they changed something in design and answer was no. So asked if there was bad batch of OPA2140 or something else which leaded to damage of OPA2140. Response was that they do not know but all defective units they received back are working after replacement of OPA2140. And they replied they are soon sending new batch out to sellers and only change on manufacturing process on them according to topping is included heavy testing 100+ hours. They believe there is no change of design needed so either it was bad batch or "inappropriate process for OPA2140" whatever that means. They also replied that if they heavy testing on defective-reparied units will be without failures it will mean it was probably bad batch of OPA2140.

 

[david99]

They weren't in stock until a week or so ago though. I'd like to not deal with returning if the unit breaks which is unfortunate since this unit has everything I would want.

I communicated with them on 25.2.2019 when they confirmed they have only units with serial starting 19015 on stock. Hard to say if something changed by the time. But if you will ask them please confirm in this thread current status. Thanks

 

[gypsygib]

Could the OPA2140 defect cause intermittent noise in the heaphone at high gain?

I ask because like another user I hear unwanted noise like antenna noise only in the right ear on high gain with RCAs plugged in. Need to know if I should RMA or if it's normal.

 

[Wolven]

Try headphones on high gain, you may hear it as well in one of the channels.

I tried with the headphones in high gain, but didn't detect interference. With the speakers it comes and goes in DAC mode. Ohh well.

 

[gypsygib]

I tried with the headphones in high gain, but didn't detect interference. With the speakers it comes and goes in DAC mode. Ohh well.

Did you play audio through the headphone and have the RCAs plugged in? I find it noticeable after I play audio through the headphones then stop instead of just switching from line out to headphone. It definitely comes and goes and I have to focus to hear it.

Also low impedance headphones make it more noticeable.

 

[amirm]

Wait then how about that OPA2140?

Based on what I understand, it is the soldering of the parts that resulted in this failing. So the fix is more care in manufacturing and not a design issue.

 

[gypsygib]

Here's a recording of the noise for anyone interested.

It's louder in person in the headphones as it was recorded with a cell phone and there's background noise. It's most noticeable around 9 seconds.

https://soundcloud.com/devin-maguire-76845986%2Fdx3-pro-noise-high-gain

 

[agjell]

Based on what I understand, it is the soldering of the parts that resulted in this failing. So the fix is more care in manufacturing and not a design issue.

If that really is the case, I guess some owners of faulty units will try to fix this themselves. Is there a higher performing chip that would work as a direct replacement for the OPA2140?

 

[amirm]

If that really is the case, I guess some owners of faulty units will try to fix this themselves. Is there a higher performance chip that would work as a direct replacement for the OPA2140?

Fixing SMD parts is not for faint of heart. At any rate, if the problem is there, it will damage the opamp in which case you have to replace it. I think it is best to send it back to them for fix.

 

[david99]

Based on what I understand, it is the soldering of the parts that resulted in this failing. So the fix is more care in manufacturing and not a design issue.

Hi Amir, thanks for sharing this is info you have from topping?

 

[amirm]

Hi Amir, thanks for sharing this is info you have from topping?

Yes although there is some language barrier on interpreting what they are saying.