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Review and Measurements of Topping DX3Pro DAC and Headphone Amp

flowzeph

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Make sure that the volume is not full blast when you switch from speakers to headphones . It's always good to turn the volume back down when you turn it off at night and before connecting your IEM. So far, my DX3 pro is behaving nicely but I intend to check the inside very soon for a cleanup and soldering inspection. The serial is 19025930xx
Ahh I see. I don't think I'll be using IEM's at this stage. Would there be the same cause for concern for the DT1990's? And would you recommend doing the same for them?
 

auronthas

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Ahh I see. I don't think I'll be using IEM's at this stage. Would there be the same cause for concern for the DT1990's? And would you recommend doing the same for them?
I would suggest you reduce the DX3 Pro volume to -30 to -30dB, before you switch to headphone mode. Should be safe.
 

flowzeph

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I would suggest you reduce the DX3 Pro volume to -30 to -30dB, before you switch to headphone mode. Should be safe.
Thank you.

My apologies in advance as I have limited understanding of how the DX3 works, since
I will be exclusively using it for my PC and the DT1990's, will I need to power off/on (and additionally lowering the volume to that range) the DX3 Pro every time I shut off/turn on my PC?

If so, would it be good practice to unplug the headphones before shutting down/after booting up?
 

flowzeph

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Just turn down the volume after using it so that it will be at lower volume when you boot your computer. Watch out for not using the no volume mode.( direct sound, better sound controlled by the app, but not as safe)

Thanks a lot for the help.

Just to clarify, you're suggesting I do not use the no volume mode?
 

lator

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After a bit of reading though, some people have had their IEM's damaged from the DX3 Pro which is very concerning and would like to know if anyone could clarify if I should be cautious/wary? I will be receiving the DX3 Pro within 3 business days at the same time that I'm receiving a new pair of Beyerdynamic DT1990's, with the intent to drive them with this DAC/Amp. However now I'm unsure if I should be cautious/wary of any potential damage that could be caused by a faulty unit.
This unit doesn't have protective circuit to prevent headphone or hearing damage. There has been some reported cases of damaged headphones due to DC voltage reaching the driver coils.
 

flowzeph

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This unit doesn't have protective circuit to prevent headphone or hearing damage. There has been some reported cases of damaged headphones due to DC voltage reaching the driver coils.

That's what I'm afraid of currently. Are there any preventative measures (aside from reducing the volume as suggested) that could be reliably taken? I've seen some posts about buying a separate power adapter (15V1a/15V2a) and was curious about the efficacy of that method.

Another related note as I've seen a few posts and videos about receiving the wrong power adapter(EU plug when in USA for example), if I receive a non-Australian power adapter, would this particular product be inadequate?

https://www.amazon.com.au/LENCENT-U...power+adapter&qid=1562584163&s=gateway&sr=8-4
 

Music1969

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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?
 

Noob2313

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I asked Amazon (USA) for a replacement [for the first unit, which died after just 5 hours of run time]. It arrived yestered and died after 24 hours of run time...

At Amir's urging, I contacted the Amazon seller, Shenzen Audio, to see what they wanted to do about this double failure.

They contacted the factory, who said there was "a quality issue with the PCB."

They're going to send me a replacement unit direct from the factory, but advised that "the factory will take a few days to upgrade it." Whatever that means??
 
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thomasjast

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At Amir's urging, I contacted the Amazon seller, Shenzen Audio, to see what they wanted to do about this double failure.

They contacted the factory, who said there was a "quality issue with the PCB."

They are going to send me a replacement unit direct from the factory, but advised that "the factory will take a few days to upgrade it." Whatever that means??

Means you're getting a modded model with a different op-amp and impedance by the looks of it.
 

Music1969

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The volume doesn't have anything to do with DSD decoding , it's just a volume control.

Main reason I asked is because digital (not analogue) volume control of 1 bit SDM (DSD) can be a complicated topic. I'm not sure it's so straight forward.

Even today, how ESS do it is a little bit of a 'black box'. I can't find much info about how AKM do it.

Also, when I refer to digital volume control, I'm referring to the volume knob of the DX3 Pro (the DAC chip's digital volume control) not the software player's digital volume control.
 
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Veri

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Main reason I asked is because digital (not analogue) volume control of 1 bit SDM (DSD) can be a complicated topic. I'm not sure it's so straight forward.

Even today, how ESS do it is a little bit of a 'black box'. I can't find much info about how AKM do it.

Also, when I refer to digital volume control, I'm referring to the volume knob of the DX3 Pro (the DAC chip's digital volume control) not the software player's digital volume control.
Considering in RME ADI-2, when using direct DSD the digital volume control is automatically unusable/off, I can only assume it is using some hybrid mode or likely >PCM conversion method to keep the digital volume in control.

As you say this is much of a 'black box' as far as I can see.
 
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amirm

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Even today, how ESS do it is a little bit of a 'black box'. I can't find much info about how AKM do it.
I can't find any info either other than it being able to attenuate DSD:

1562655770610.png


If the disable bit is not set, DSD as well as PCM to go to the same attenuator subsystem.
 
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amirm

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Oh, looking at it again, it seems like if you enable volume control, DSD is converted to PCM and level adjusted. Otherwise it bypsasses the conversion to PCM and goes directly to output filter (Switched Capacitor Filter/SCF).
 

flowzeph

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Just received the Topping DX3 Pro however have not received my DT1990's yet so I'm using my old DT990's.

Going from my iFi nano BL to the DX3 is almost night and day. The sound seems to widen and bring out the musicality of the DT990's much more, the sibilance is tamed quite a bit and the clarity is absolutely sublime and crystal clear. The lack of channel imbalance is also very welcoming coming from the nano. I do very much hope this unit lasts because my experience so far has been mesmerizing.

Big thanks to Amir for the review.
 

Music1969

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Hi @amirm

Any chance you can measure the headphone output distortion, the same way you measured for the Chord Hugo2, testing against real headphone loads?
 

letsgoo

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This unit doesn't have protective circuit to prevent headphone or hearing damage. There has been some reported cases of damaged headphones due to DC voltage reaching the driver coils.
Is there any Aftermarket adapter or socket for that function?
 

pauze

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Ah yes, i forgot to ask.

Anyone here with any 600ohms HP ? I will be using the Beyer T1 (gen 1) on the DX3 Pro.

As such, going by @amirm tests, i believe it will be able to drive it successfully ?

I have Beyer DT880 600ohms. I feel the DX3pro can drive my headphones to uncomfortably loud volumes on most of my music, and that's close to max volume in high gain mode. On quieter tracks, I'd love to have more room to go louder that the DX3 allows, but they still play loud enough for me to enjoy. I am looking to perhaps add an Atom to my setup for those times I want more power with those headphones, but am in no rush considering how loud it already plays.
 
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