Review and Measurements of Topping DX3Pro DAC and Headphone Amp

[Veri]

Hello to everybody, I am new of the forum and I find these technical reviews fantastic.

Going back to measurement results, I can not understand why the line level output is worst than the headphone output.
The FFT shows more noise on the line output, while the headphone output looks much better with lower noise floor and less spikes and this is confirmed by a higher measured SINAD.
So according to these results it seems better to feed an amplifier from the headphone output instead of rca line...

Feeding it from the amplifier output and using the (digital) volume control on the dx3pro for volume seems ideal, yes.

 

[pii75]

Is it possible to repeat the linearity test using headphone output? I am just curious to see if it gains some bits more...

 

[Krunok]

Going back to measurement results, I can not understand why the line level output is worst than the headphone output.

Probably different op-amps were used in output buffer line out stage and headphone output stage.

 

[Krunok]

Is it possible to repeat the linearity test using headphone output? I am just curious to see if it gains some bits more...

It probably would as it has lower noise floor, but that difference is not something you would be able to hear.

 

[Veri]

Probably different op-amps were used in output buffer line out stage and headphone output stage.

While a plausible explanation, I'm not inclined to think that would have as much of an effect.

 

[Krunok]

While a plausible explanation, I'm not inclined to think that would have as much of an effect.

"As much"? I would say the difference is rather small..

 

[Veri]

"As much"? I would say the difference is rather small..

I'd like to think that any suitable opamp should perform nearly the same, some dB in SINAD seems a lot to me but idk ..

 

[Krunok]

I'd like to think that any suitable opamp should perform nearly the same, some dB in SINAD seems a lot to me but idk ..

It is basically 106dB vs 108dB, so not really a big deal.

 

[pii75]

It is basically 106dB vs 108dB, so not really a big deal.

In any case we can agree that these differences are not due to AKM chip, otherwise same noise would be find on headphone output too.

 

[pii75]

It is basically 106dB vs 108dB, so not really a big deal.

I agree that differences are small and would not be able to hear, but I think it is the same disappoint we have with the "ESS hump", we desire to look at a beautiful linear graph regardless how it sounds... The same here I would like to look to a flat line in the linearity test graph because AKM could do it

 

[amirm]

Hello to everybody, I am new of the forum and I find these technical reviews fantastic.

Going back to measurement results, I can not understand why the line level output is worst than the headphone output.
The FFT shows more noise on the line output, while the headphone output looks much better with lower noise floor and less spikes and this is confirmed by a higher measured SINAD.

Welcome to the forum. On your question, the dashboard for headphone output uses 600 ohm load which is far smaller than 100K used for DAC testing. That lower impedance can suppress noise interference. In addition, the mains leakage profile changes between these two outputs and that is mostly what is visible on the graphs.

So there is really no difference to speak of there.

 

[pii75]

Welcome to the forum. On your question, the dashboard for headphone output uses 600 ohm load which is far smaller than 100K used for DAC testing. That lower impedance can suppress noise interference. In addition, the mains leakage profile changes between these two outputs and that is mostly what is visible on the graphs.

So there is really no difference to speak of there.

Thanks for the explanation.
Looking to other linearity tests done on other devices, I see the number of bits are more or less the SINAD value divided by a 6 factor. With a SINAD of 106 dB I was expecting at least 17,5 bits. Why this is not true in this case? Sorry bother you with this question, I know this is not important for the evaluation of this specific DAC that seems very good (and probably it will be my christmas gift), it's a more generic question to understand the meaning of the tests. Thanks

 

[amirm]

Looking to other linearity tests done on other devices, I see the number of bits are more or less the SINAD value divided by a 6 factor. With a SINAD of 106 dB I was expecting at least 17,5 bits. Why this is not true in this case?

There is no direct correlation between SINAD and linearity. Linearity filters out distortion for example. So that is not a contradiction.

 

[Varenyk]

Hello Amir, registered so I could ask you this. I understand that you mainly focus on objective experiences and measurements but I was wondering how you think this unit sounds.

With the headphones you've tried, do you reckon its neutral / on the leaner side like say JDS The Element or does it have a tilt towards brightness or darkness / warmth?

Also, when and where can I get this? I've been searching for a DAC / AMP for the longest that has Optical in, Digital volume control, volume control for active speakers, <5ohm headphone out impedance, sounds neutral to warm, and doesn't cost an arm and a leg.

 

[amirm]

Hello Amir, registered so I could ask you this. I understand that you mainly focus on objective experiences and measurements but I was wondering how you think this unit sounds.

With the headphones you've tried, do you reckon its neutral / on the leaner side like say JDS The Element or does it have a tilt towards brightness or darkness / warmth?

Also, when and where can I get this? I've been searching for a DAC / AMP for the longest that has Optical in, Digital volume control, volume control for active speakers, <5ohm headphone out impedance, sounds neutral to warm, and doesn't cost an arm and a leg.

He there. Welcome to the forum. The sound is neutral and any tonality you hear is reflective of the sound of your headphones, not the amp. At higher volume, any leanness/brightness is usually the result of lack of power and that is not a problem here.

As to schedule, I have not asked them but given the fit and finish of this unit, I say it is very close to production.

 

[Varenyk]

He there. Welcome to the forum. The sound is neutral and any tonality you hear is reflective of the sound of your headphones, not the amp. At higher volume, any leanness/brightness is usually the result of lack of power and that is not a problem here.

As to schedule, I have not asked them but given the fit and finish of this unit, I say it is very close to production.

Thank you for the quick response. I appreciate what you do and keep up the great work.

Are there any other units you'd recommend that would match my above mentioned criteria aside from this one?

Only other one that nearly met all of my criteria was the Matrix Mini-i but it had ~12 ohm headphone out which made all the bass disappear on my Fostex THX00. (~30ohm headphones?)

Also, how warm/hot to the touch does this topping unit get? Say after 1-2 hours of being on.

 

[avatar]

Great amp! I hope the a50 will be even better.
what is the max voltage output in low/high gain ? I think you should report it in every amp review.
thanks

 

[Peib]

This is cool to hear.

I've got a mx3 on the way to compare that headphone amp to my o2. Looking at specs it's not the same as dx3, but still has potential with low output impedance.

A50 is probably what I ultimately want. D50 as DAC, mx3 for powering speakers and eq, A50 has headphone amp..... Yes

Any idea about when it will be released?

 

[bravomail]

Thx for the review! For the price though I would feel much more confident with Schiit Modi3 (which you measured excellent, same(?)AK DAC chip) and massively powerful Schiit Magni. Cause I would still have my doubts about built-in headphone amp of this new Topping unit.

 

[andreasmaaan]

Cause I would still have my doubts about built-in headphone amp of this new Topping unit.

What gives rise to these doubts? The Magni has about double the output power, but otherwise the headphone amp section of the DX3 outperforms it in every respect.