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Review and Measurements of Topping DX3Pro DAC and Headphone Amp

yue

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Jul 21, 2018
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I bought @yue DX3Pro and I have been listening to it for 3 days so far. It is rock solid and working as well as my original unit. I will keep reporting as I continue to use it.

Problem used to occur almost every day under my heavy use. I mentioned above that @Toku and I once ran continuous tests independently for very long time (@Toku ran it for many days. I ran it for over 18 hours) but unable to trigger problems. But we did witness it (in my case a lot) in our daily use. So I was wondering if there're anything related to user interactions --- such as start/stop/switch songs of different formats/sample rates more often, or static electricity I carry during winter (this is Topping's hypothesis) could cause the issue.

I would recommend trying a spark ignitor (to simulate static electricity carried by humans, or power fluctuations caused by a poor adaptor) and see if it triggers the problem.

Topping's static electricity hypothesis make sense to me, as both my Macbook Pro and the unit use 2-prong adaptors and have a light vibrating feeling when I touch the metal surface. Though I didn't feel shocked when the device stopped playing.
 
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Jestercow

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Jan 4, 2019
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A little wooden cube or anything the right size just under the adapter would be cheaper.
More worried about a kid, pet, or clumsy self tugging the cord sideways; pigtails let the cable unplug before stressing anything expensive.
 

archangel015

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Feb 8, 2019
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Does dx3pro need burning in? or no need to? Also, can I get recs for bassy headphones? I currently have an hd6xx.
 

777

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I see, coz I remember audio gd products are like burned in or something.

All the audio product need the burn in. The difference is if you want to take into account this phenomenon. On the speakers is most intense. Sometimes, the devices with powerfull negative feedback are much more "immune" and you doesn't feel it(like DX3Pro). GD products are in most cases with minimal global negative feedback and is likely to feel the burn-in phenomenon of the electrolytic capacitors.
 

Stonetown

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I see, coz I remember audio gd products are like burned in or something.
No its a big big big tall tale, so big that too many believes it. But all skilled electronic engineers know its fake news. However non-engineers or non educated "self-learned" think they know better than the experts as with many other things in the modern society (parents stops vaccinating their children etc). Its truth that the less you know the more you think you know, unfortunately. Especially all misconceptions by many here who don't know how to show and test scientifically statistically that something is thru or just a self scam or coincidence.
Be critical to all those self proclaimed experts!
Cheers
/Per
 

Stonetown

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All the audio product need the burn in. The difference is if you want to take into account this phenomenon. On the speakers is most intense. Sometimes, the devices with powerfull negative feedback are much more "immune" and you doesn't feel it(like DX3Pro). GD products are in most cases with minimal global negative feedback and is likely to feel the burn-in phenomenon of the electrolytic capacitors.
One more bullshit statement!
 

777

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One more bullshit statement!

Good joke :). Did you hear about electrolytic capacitor formatting ? Aging ? Re-formatting ? About aluminium oxyde layer which act like a dielectric ? Did you know the chemistry of the electrolytic capacitors ? Are you electrical engineer ?
 
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Stonetown

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Good joke :). Did you hear about electrolytic capacitor formatting ? Aging ? Re-formatting ? About aluminium oxyde layer which act like a dielectric ? Did you know the chemistry of the electrolytic capacitors ? Are you electrical engineer ?
Yes, Yes, YES!
And we also know that there is never ever anyone in the whole world who passed an official scientifically blind test listening to different capacitors, different cables, etc. I am sorry to inform you. But keep on and believe that you can. you are the best! ;)
Cheers,
/Per
 
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y845133y

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Jan 28, 2019
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I got the TI simulation tool for TPS54331 and set it as below.
* Input voltage: 15v , Output voltage: 10v , Output current: 0.5amp
The L1 is 47uH same as DX3-PRO. The Input and output capacitors is Panasonic 100uF/25v aluminum cap (ESR: 300mohm:facepalm:). The output ripple is 41.5mV.
P.png

SCH.png

Ripple1.png

Check the MLCC capacitor SPEC and select it for reducing output ripple. The 10uf, 22uf and 47uf MLCC is good for decreasing the PWM noise.
MLCC_CAP.png

Try to add a 47uf MLCC. The output ripple is 1.2mV.:)
1549883733405.png

1549883791356.png

Change the C2 to SANYO OS-CON (16SPS100M) ESR:25mohm. The output ripple is 3.5mV.:)
1549884060022.png

I think the aluminum cap is not good for PWM power output. It needs a low ESR cap.
 

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777

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Or maybe both in parallel 100uF ÷ 10uF. The output current in your simulator is too large. All DX3Pro has a 0.13A current with DAC output. On the +/-10v rails there are diodes in series.If I can insert a resistor there, I can measure the current on this rails. I'll see the ripple with the oscilloscope too.
 

rebbiputzmaker

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Good joke :). Did you hear about electrolytic capacitor formatting ? Aging ? Re-formatting ? About aluminium oxyde layer which act like a dielectric ? Did you know the chemistry of the electrolytic capacitors ? Are you electrical engineer ?
It is really not worth talking about. I guess some here would just plug in a 30 year old unit and just turn it on. Real men don't need no stinking vairacs. ;)
 

777

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This is the output voltage ripple of 10v regulator (aprox. 60mVp-p) but at the opa1612 voltage pin the situation is much better. There is a series ferrite which form a low pass filter and the voltage ripple at opa1612 pin is aprox. 9mVp-p.
 

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mikehoopes

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Aug 2, 2018
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Location
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At last i try it out my self, and i can say i am very satisfied with this dx3 dac/preamp ,just strange that i cant hear difference in quality playing between Bluetooth via phone , optical connection straight thru media player and USB thru laptop (all playing spotify) could this be because BT is very high quality or just DAC do its best job and all connections? :rolleyes:

Video:
I noticed that the BT input is louder than the USB, with both sources at 100% volume. I don't know if that has something to do with my USB driver being set to 32-bit.

That said, AAC over BT from Apple Music on my iPhone sounds good to me on the DX3 Pro. Those that hyperbolically denigrate AAC (and double-encoded AAC) should try to ABX that codec with others. It might tone down the rhetoric.
 
OP
amirm

amirm

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I see, coz I remember audio gd products are like burned in or something.
There is a lot of talk about burn in but none of that holds to scrutiny. When I borrowed the Schiit Yggdrasil the owner thought burn in made it better so I ran it for 2 weeks, making daily measurements. Not a thing changed.
 
OP
amirm

amirm

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On the speakers is most intense.
No. This was studied at Harman and found the difference in frequency response was negligible once the driver was put in a box. Dr. Toole says it best in his book:

index.php
 

splkn

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Jan 15, 2019
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I got the TI simulation tool for TPS54331 and set it as below.
* Input voltage: 15v , Output voltage: 10v , Output current: 0.5amp
The L1 is 47uH same as DX3-PRO. The Input and output capacitors is Panasonic 100uF/25v aluminum cap (ESR: 300mohm:facepalm:). The output ripple is 41.5mV.
View attachment 21719
View attachment 21718
View attachment 21720
Check the MLCC capacitor SPEC and select it for reducing output ripple. The 10uf, 22uf and 47uf MLCC is good for decreasing the PWM noise.
View attachment 21721
Try to add a 47uf MLCC. The output ripple is 1.2mV.:)
View attachment 21723
View attachment 21724
Change the C2 to SANYO OS-CON (16SPS100M) ESR:25mohm. The output ripple is 3.5mV.:)
View attachment 21725
I think the aluminum cap is not good for PWM power output. It needs a low ESR cap.
Then it is better to use Cap Tant Polymer for example these https://www.arrow.com/en/products/tcjy157m016r0070/avx
 
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