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Review and Measurements of Topping DX3Pro DAC and Headphone Amp

777

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On the PCB, close to the power supply (left bottom), between 15VDC and GND, it does have a capacitor. so why would you worry about the power supply so much?


View attachment 20364

As you can see my friend, the high frequency noise it is still there and more, it is at the all signal outputs. Can that noise influence the perception of sound ? I don't know but the next circuits stages may not be very happy with it.
 

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kukocz

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As you can see my friend, the high frequency noise it is still there and more, it is at the all signal outputs. Can that noise influence the perception of sound ? I don't know but the next circuits stages may not be very happy with it.
Do you have any LPS to make a comparison? Maybe a test with 10xAA batteries could be performed to se the difference?
 

777

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The same RCA output but with my lab linear power supply at 15v and 1A settings. The HF noise went down.
 

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777

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The current consumption in a "DAC"-mode is at 0,1A.
 

splkn

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Mine has no problems with 3.5mm using my HD650. I remember much earlier in the thread someone having the same problem though (with full insertion).
Tell me please, do you recommend HD650 for listening with Topping DX3 Pro?
 

splkn

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I think it's the connection from qualcomm bluetooth to the 4493 chip. For USB there is XMOS in between, for the qualcomm there is little software to play with only the relay to protect from popping sound, which apparently makes it click constantly instead. I doubt they can solve it without hardware revision.
No relay is not in the digital part of the circuit.
 

Veri

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Tell me please, do you recommend HD650 for listening with Topping DX3 Pro?
I hear no difference between THX AAA and DX3 so that is saying something. It's very clean output. If you want distortion-less, pure audio then yes I fully recommend.
 

peder2tm

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As you can see my friend, the high frequency noise it is still there and more, it is at the all signal outputs. Can that noise influence the perception of sound ? I don't know but the next circuits stages may not be very happy with it.
Is the noise also present at the output when playing silence into a load? I am surprised if that amount of noise is not audible
 

chrisliuboy

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Like other one said, dx3 will probably filter most of that, i still think that dx3 needs a slightly better power supply,
Yep, I replaced one from Mean Well, just for the US plug and longer cable, also got feedback from Topping just saying if you want use another adopter just watch for the ripple, which is nice.
 

noobie

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That is just weird! But hey, good stuff.

I had the Bluetooth stop working as well last week... in my case, though my Bluetooth keyboard and mouse also stopped working, so it turned out to be that my laptop’s internal Bluetooth hardware’s driver had somehow gone bad (figured out by running Windows 10 Bluetooth troubleshooter). The troubleshooter did whatever magic it does and all was right again. Probably not what happened in your case but if it happens again you might want to try out the troubleshooter buried in Windows (if Windows is what you are using)
 

777

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Is the noise also present at the output when playing silence into a load? I am surprised if that amount of noise is not audible

It was not the load at all. You can not directly hear that high frequency noise. It is beyound the audio band but you lose the air of the instruments, you lose the depth of the scene, maybe the right timbre of the instruments. You will feel all of that on the highend audio system. Tomorrow I'll show you another upgrade in the power supply. It is about charging current of the first step-down converter, TPS54331. This DAC, Dx3Pro, is a very good, it could be better than many expensive products, deserves all that is best.
 

kukocz

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Dx3 has quite a lot of jitter (inaudible dB range) and low linearity. Those are all at audible frequencies. As a second tier DAC, it doesn’t need the best power supply at all, unless you can show a cleaner fft when using a better power supply.
Can't wait to see measurements...
 

MattG

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Re: random power-offs...

It happened to me just the other day. Mine is connected to a Raspberry Pi (model 3 IIRC), which I believe is USB2 only. Running DietPi (Linux-based). I leave it playing music 24/7 in my office. It was playing one night, and when I got up in the morning, it was shut off. As soon as I powered it back on, the music came through (i.e. the RPI + player software was still running just fine).

I think this has only happened to me a couple times, and I got mine back in late November... I think I have a 15v PSU I can try with. Although, how long do I let it run before declaring the new power supply a success? It seems to happen about once a month currently.

On Sunday, Jan 13, I found my 15v PSU. It's a MeanWell laptop-style brick (GS90A15-P1M) rated for 6 amps. Ludicrous overkill for the dx3pro, but it's what I have. At any rate, I swapped out the stock cheapie power supply for this one. We'll see if I have any more unexpected power-off events in the next month or so. I'm using this thread as my notes for when I did the PSU swap. :)
 

Stein

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Re: random power-offs...



On Sunday, Jan 13, I found my 15v PSU. It's a MeanWell laptop-style brick (GS90A15-P1M) rated for 6 amps. Ludicrous overkill for the dx3pro, but it's what I have. At any rate, I swapped out the stock cheapie power supply for this one. We'll see if I have any more unexpected power-off events in the next month or so. I'm using this thread as my notes for when I did the PSU swap. :)

Sorry, I have to ask this again from another member here. By random power-offs, do you mean a complete shutdown or does the LCD display a dot, like it does in standby mode?
 

yue

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also weird thing in @amirm's test is that in the first graph it shows a 0.0004% THD+N for 1Khz tone. However, in the THD+N versus frequency graph it's greater than 0.001% at 1KHz. why?
 
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MattG

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Sorry, I have to ask this again from another member here. By random power-offs, do you mean a complete shutdown or does the LCD display a dot, like it does in standby mode?

Actually, it is the latter, i.e. LCD still displays a dot, as though it's in standby mode. At least this is how it's been for all my cases. (Not sure if others have had a true/complete power-down.)
 

Stein

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Actually, it is the latter, i.e. LCD still displays a dot, as though it's in standby mode. At least this is how it's been for all my cases. (Not sure if others have had a true/complete power-down.)
We seem to have experienced the same issue then. Mine's been stuck in standby mode, but according to the Topping service people, it might not be the adapter.
 
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