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Review and Measurements of Topping DX3Pro DAC and Headphone Amp

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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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. ;)
 
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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.
 

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.
 

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:

 
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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
 

rebbiputzmaker

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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:

What he is writing is correct, but not every single circumstance. For example very old (vintage) drivers with accordion surrounds can be very stiff after years storage etc. The resonance frequency will change with use.
 

Killingbeans

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Are you electrical engineer ?
There's a big difference between working as an engineer with high precision and/or power circuits in the realm of RF, and working with "simple" audio.

When working with RF you have to account for the fact that EVERYTHING becomes a filter at high enough frequencies and that all kinds of parasitic effects come to play. But practically none of these "electrical engineering problems" have any impact below 20kHz (or 100kHz for that matter).

One of the snake oil vendor's favorite tricks is to cherry pick some phenomenon that's a genuine PITA for a NASA engineer trying to make a satellite do nearly impossible things, and claim that this specific phenomenon is also a real hindrance in the pursuit of "audio nivana", when in fact it's completely irrelevant. It's based on 'engineering', so it has to be true, right?

Just because something is a real problem in certain parts of the field of electrical engineering, doesn't mean it's also relevant for audio.
 

amirm

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What he is writing is correct, but not every single circumstance. For example very old (vintage) drivers with accordion surrounds can be very stiff after years storage etc. The resonance frequency will change with use.
Modern drivers do too but once you put them in a cabinet, the impact becomes very small. Regardless, no one is talking about "very old" drivers. Statement was made generically about all speakers.
 

NTomokawa

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I think transducer break-in (or burn-in) has more to do with psychoacoustics than anything else. That is, the mind adapts to the sound.

Granted, rigourous measurements are few and far between.

But transducer break-in at least has some degree of truth in it. Wait until we enter the domain of "cable break-in"...
 
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I think transducer break-in (or burn-in) has more to do with psychoacoustics than anything else. That is, the mind adapts to the sound.

Granted, rigourous measurements are few and far between.

But transducer break-in at least has some degree of truth in it. Wait until we enter the domain of "cable break-in"...
My 1000.00 power cord sounded like my 10.00 power cord out of the box, and after 500 hours of burn in, it started to open up and sound like the 1000.00 power cord I paid for. You mean to tell me that was all in my head?:eek:
 
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My 1000.00 power cord sounded like my 10.00 power cord out of the box, and after 500 hours of burn in, it started to open up and sound like the 1000.00 power cord I paid for. You mean to tell me that was all in my head?:eek:
Did you burn in the wiring in your house? It will make it sound like a $2,000 power cord. At least in your head. :)
 
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