• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Review and Measurements of Topping NX4 DSD Dac and Portable Headphone Amplifier

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
15,435
Likes
9,473
Location
Seattle Area
#1
This is a detailed review and measurements of the Topping NX4 DSD portable headphone amplifier and DAC. It is on a kind loan from a forum member and highly anticipated review. Retail price (shipped from China) on Amazon with free shipping is USD $160 as of this writing. The unit has internal battery so truly portable.

Aesthetically from box design and the DAC itself, it oozes quality and nice industrial design. Nothing cheap feeling. The packaging alone would make you think you are buying a luxury product yet the price says otherwise. I have no idea how Chinese companies like Topping pull this off:

Topping NX4 DSD DAC and headphone amp Review and Measurements.jpg


You want to know why I never, ever want to get in the business of making audio products? This is the proof. :)

Feature wise, this is a rich product with great format support with PCM up to 768 kHz and DSD512. There are two gains: high and low. A bass boost switch. And a jack for that is for both line in and out (!). I did not test this but the unit can be used as a pure headphone amplifier by using this jack and line out for DAC-only use. My testing was with the headphone jack as that is the most common use.

Battery life which I did not test is stated to be 7.5 hours.

As is with all Topping products, the unit comes with printed documentation that includes measurements from Audio Precision analyzer. Full regulatory certification is included which even some high-end audio equipment lacks. Those of you who are worried about "EMI" should be shopping products that have such certification.

My objective testing was with ASIO4ALL ASIO wrapper. For subjective listening I used the USB class driver in Windows 10 creators edition using Roon player for bit-exact playback.

Measurements
Let's start with our usual dashboard with gain setting in low but max volume:

Topping NX4 DSD DAC Dashboard Low Gain measurement.png


We see nice output level of 2 volts but with slight channel imbalance. Distortion is very low. SINAD which is the inverse of that, shows distortion and noise free dynamic range of 104 dB, well in excess of what we need for CD playback (93 dB with dither).

Clicking the switch to high gain and max volume, performance degrades substantially:
Topping NX4 DSD DAC Dashboard High Gain Max Volume measurement.png


We get super nice boost in output level, nearing 6 volts. But distortion has gone way up (relatively speaking). Fortunately bringing the volume knob down a few clicks gets us back to excellent performance:

Topping NX4 DSD DAC Dashboard High Gain Least Distortion measurement.png


5.1 volts output with good distortion numbers.

Let's look at frequency response:

Topping NX4 DSD DAC frequency Response measurement.png


Not ecstatic about the droop at either end of the spectrum although the effect on those of us over 25 years old (ahem), is negligible. Still, I like to see ruler flat response.

Channel imbalance in mid-frequencies where our hearing is most sensitive is 0.06 dB so not a concern. More to come on this later at other volume levels.

Harmonic distortion and noise is excellent. Here I compare it to the well performing portable Sabaj Da3 and Dragonfly Black:

Topping NX4 DSD DAC THD+N vs frequency measurement.png


We see that the Topping NX4 DSD is in a different class. Its distortion is so low that it causes my analyzer to have trouble reading it (as indicated by those "T" symbols). I am working on refining the analyzer settings to not do that.

Digging into the spectrum of the distortion we see:

Topping NX4 DSD DAC THD+N 1 kHz measurement.png


The Topping NX4 DSD has substantially lower amount of second harmonic compared to Sabaj Da3. It is also well behaved, lacking that "hump" that exists in the output of Sabaj Da3.

Same story continues in Jitter test:
Topping NX4 DSD DAC Jitter measurement.psd.png


Note that compared to my older analyzer, these are higher resolution FFTs, showing USB packet noise that was not visible before. At -120 dB these are not audible concerns at all. But like to see them suppressed regardless.

Let's get back to channel balance and see what happens when I turn the volume down from max to min manually and plot the difference between left and right (in dB on the right vertical axis):

Topping NX4 DSD DAC Channel Balance measurement.png


Tracking is good until about -40 dBV (-45 dB attenuation), staying below 0.2 dB of error. From there, it takes a nosedive so better not operate it beyond that region. See my subjective listening tests on the impact of this practice.

On output impedance, I expect to see the typical 10 ohm but was pleasantly surprised that it was much lower at just 0.9 ohms:

Topping NX4 DSD DAC output impedance measurement.png


I love to see this in their desktop products! It eliminates any worry of interacting with the headphone to change its frequency response.

Let's see the output voltage (and hence power) relative to distortion:
Topping NX4 DSD DAC output vs distortion measurement.png


For reference I am showing the Sabaj Da3 at 33 ohm. We see that the NX4 DSD sails way past it with lower distortion and higher output voltage/wattage. Measured output power as indicated on the graph is about half of what Topping specs I think. The discrepancy can go away by climbing up the distortion line instead of staying at its minimum level.

Subjective Listening Test
In the interest of getting this review out quickly and reducing my significant backlog of products to review :), I did not perform an AB tests. Instead, I just plugged in different headphones and listened to my music library.

On channel imbalance, I only hear that at the extreme low end of the volume level, close to muting. This was with both my Sony headphones and sensitive IEMs. Definitely not a concern in my listening experience.

Bass boost is nicely done when listening to mid to lower volume levels. It nicely fills in the low and adds impact without any distortion. It is especially good for compensating for less than good feel of IEMs. Once you start hearing distortion though, adding the bass boost really screws things up. So only use it for less then ear bleeding levels. :)

With my power hungry Sennheiser HD-650 headphones, there was plenty of volume. I always want more headroom with this headphone when I can get it :), but otherwise, it is a fine pairing.

Other than this, the unit is delightful. I am listening to my music library while composing this review and enjoying it.

Conclusions
Let me make a confession before giving you my conclusion: people accuse me so much of being in Topping's pocket based on good reviews I have given them that I secretly wish that some of their products don't do well so that I can say that and get out of jail!!! :D Alas, that opportunity is not here yet. The Topping NX4 DSD is a superb portable DAC and headphone offering at super attractive pricing.

Yeh, channel balance could be better and frequency response droops a bit. But other than that, Topping shows one more time that proper engineering matters. And design verification matters. That attention to quality and execution matters. And bargain prices matter.

The DSD NX4 has impressed me greatly. It would be my choice for a portable headphone+DAC or a stand-alone desktop DAC for that matter. All the positive vibes on this unit are indeed true.

Recommended!

As always, questions, comments, corrections, etc. are welcome.

-----
If you like this review, please consider donating funds for these types of hardware purchases using Patreon (https://www.patreon.com/audiosciencereview), or upgrading your membership here though Paypal (https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054).
 
Last edited:
Joined
May 21, 2018
Messages
93
Likes
48
#2
Im extatic to see how these chi-fi (no racism at all here) just demolish "brand" named products. Truth be told the difference between sabaj and this is not gamebreaking for me as i already enjoy it so much BUT next time i get to splurge ill deffo look at topping as a serious contender for my bucks.

Simply amazing.
 
Joined
May 20, 2018
Messages
10
Likes
0
#5
Was waiting for this review to come out!! Thanks @amirm !
Is it possible to show the frequency response with bass boosted - want to understand how the boost is applied. Thanks!
 
Joined
May 21, 2018
Messages
93
Likes
48
#6
Is there a chance to see what is sabaj capable on balanced output and not maxed volume (as we see there is degradation in quality in some products when volume is maxed and to check is the "balanced" usage worthwhile or is it just a marketing gimmick). Also id like to see the whole shebang like pure dac oput on topping since it could possibly outperform even these stellar results.
 

Thomas savage

Look into my eye..
Moderator
The Watchman
Patreon Donor
Joined
Feb 24, 2016
Messages
6,408
Likes
2,661
Location
uk, taunton
#7
$ 10 to the first guy to paint “ topping shill” on ya camper VAN..

This unit looks great, congratulations to topping on another fine effort.

Probably not practical but I’d love us to take two unmarked boxes with known measured performance ( one close to ideal another some way off but ‘popular ‘) to a Audio show and conducted proper blind listening tests. Not to shame or promote brands but to dig into whether worse measured performance really means less ‘ preferable ‘ sound.

Maybe the results would be no better than random but that in itself would be enlightening imo.
 
Joined
May 21, 2018
Messages
93
Likes
48
#8
The veils would be lifted for sure. Tho not the kind of veil lifting they like to dribble about.

Side note, i got a friend that makes stuff (audio) ill see if i can drag him to forum since he really is a wunderkind. He once conducted an experiment with some beast of his and audio cables. There was a curtain between the listeners and amp so they didn't know what was playing. He connected cheap cables and and told them they are cheap copper wire for mains he uses. They didn't like it, then he connected a beast cable at the time, something reaching 250 per mono meter. They were amazed at the clarity and punch of the sound. After listening for good 15 minutes he told them he didnt change the cables. Everyone just left without a word. Story goes that a lot of that elitist circle jerk wont talk about him at all. Portraying him as charlatan. Stunt with no name boxes playing would be a sight to see for sure.
 

dc655321

Active Member
Patreon Donor
Joined
Mar 4, 2018
Messages
266
Likes
155
#9
Was waiting for this review to come out!! Thanks @amirm !
Is it possible to show the frequency response with bass boosted - want to understand how the boost is applied. Thanks!
The Topping site shows measurements of the bass boost effect - starts at 1kHz and rises to 5 dB at about 40Hz.

Using the NX4 DSD with my HD-6xx, the bass boost fills out the headphone's somewhat anemic sub-bass quite well at lower listening volumes.
However, the extra weight in the 100-200 Hz region does make the already warm 6xx a touch muddy. Like I said, at lower volumes it's a nice effect.
 
Joined
May 15, 2018
Messages
15
Likes
4
#10
Thanks!!! So is this the best measured portable device right now? How would it compare against Chord Mojo? With the new equipment is it correct to compare devices against each other?
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
15,435
Likes
9,473
Location
Seattle Area
#11
Think Amirn missed out the Linearity test readings on this though.
Yeh, realized that right before going to sleep. :) I had forgotten to export it out of photoshop so did not see it. Here it is:

Topping NX4 DSD DAC linearity measurement.png


As noted, variations are almost the same as my analyzer itself so good response goes to 120 dB/20 bits.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
15,435
Likes
9,473
Location
Seattle Area
#12
Is there a chance to see what is sabaj capable on balanced output and not maxed volume (as we see there is degradation in quality in some products when volume is maxed and to check is the "balanced" usage worthwhile or is it just a marketing gimmick).
I have bought the parts but have not yet built the cabling to measure balanced. With Michael coming this week, measuring the Benchmark DAC3 will be a priority. After that I will try to free up some time to build that.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
15,435
Likes
9,473
Location
Seattle Area
#13
Thanks!!! So is this the best measured portable device right now? How would it compare against Chord Mojo?
The Chord Mojo was on load unfortunately so I don't have it to compare. They are both good units though.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
15,435
Likes
9,473
Location
Seattle Area
#14
With the new equipment is it correct to compare devices against each other?
Not quite yet. I am still optimizing the settings of the new analyzer. Good news is that when I do that, the results are agreeing. So while you can compare the old and new reviews, just don't go down to minute detail. :)
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
15,435
Likes
9,473
Location
Seattle Area
#15
The veils would be lifted for sure. Tho not the kind of veil lifting they like to dribble about.

Side note, i got a friend that makes stuff (audio) ill see if i can drag him to forum since he really is a wunderkind. He once conducted an experiment with some beast of his and audio cables. There was a curtain between the listeners and amp so they didn't know what was playing. He connected cheap cables and and told them they are cheap copper wire for mains he uses. They didn't like it, then he connected a beast cable at the time, something reaching 250 per mono meter. They were amazed at the clarity and punch of the sound. After listening for good 15 minutes he told them he didnt change the cables. Everyone just left without a word. Story goes that a lot of that elitist circle jerk wont talk about him at all. Portraying him as charlatan. Stunt with no name boxes playing would be a sight to see for sure.
Yes, it is a balanced between telling the "audio truth" and making enemies. :) Hence the emphasis in our mission statement to have fun.
 

Thomas savage

Look into my eye..
Moderator
The Watchman
Patreon Donor
Joined
Feb 24, 2016
Messages
6,408
Likes
2,661
Location
uk, taunton
#16
Yes, it is a balanced between telling the "audio truth" and making enemies. :) Hence the emphasis in our mission statement to have fun.
we just need to take some of ‘amirs’ kebabs and rice with us and maybe some Mrs amirs pickles...

 

mi-fu

Active Member
Patreon Donor
Joined
Jun 7, 2018
Messages
244
Likes
203
Location
New York
#17
Thanks @amirm for posting another excellent review!

I have to admit I only began to notice this Chinese company since I came to this forum. Topping seem to be an outlier in the sense that its products are not plagued by careless design, poor quality control, or capricious supply-chain issues, which happen so frequently among Chinese manufacturers.

For a small startup like company, I'm impressed!
 

Krunok

Major Contributor
Joined
Mar 25, 2018
Messages
1,507
Likes
576
Location
Zg, Cro
#18
Conclusions
Let me make a confession before giving you my conclusion: people accuse me so much of being in Topping's pocket based on good reviews I have given them that I secretly wish that some of their products don't do well so that I can say that and get out of jail!!! :D Alas, that opportunity is not here yet. The Topping NX4 DSD is a superb portable DAC and headphone offering at super attractive pricing.

Yeh, channel balance could be better and frequency response droops a bit. But other than that, Topping shows one more time that proper engineering matters. And design verification matters. That attention to quality and execution matters. And bargain prices matter.

The DSD NX4 has impressed me greatly. It would be my choice for a portable headphone+DAC or a stand-alone desktop DAC for that matter. All the positive vibes on this unit are indeed true.

Recommended!

As always, questions, comments, corrections, etc. are welcome.
As we have been accustomed to here comes another detailed review. Also, nice to see that new analyser is proving itself worthwile.

P.S. If you don't make a not-so-shiny review of some Topping product any time soon I believe we will all start to suspect from where the money came to purchase that new fancy analyser.. :D :D
 

Jimster480

Addicted to Fun and Learning
Patreon Donor
Joined
Jan 26, 2018
Messages
722
Likes
290
Location
Miami
#19
I have bought the parts but have not yet built the cabling to measure balanced. With Michael coming this week, measuring the Benchmark DAC3 will be a priority. After that I will try to free up some time to build that.
Can't wait for that review.
Great work on this review aswell!
Another great topping product it seems.
I'll probably add it to my collection someday if I need a mobile DAC/Amp.
Right now my HTC 10 does great on its own!
 

Ron Texas

Senior Member
Joined
Jun 10, 2018
Messages
432
Likes
194
#20
Amazon lists the delivery time as July 10 to July 31 or 3 to 6 weeks. I suspect the vendor gathers orders and can't move ahead until he has a certain amount. With a lot of this Chi-fi stuff, if it breaks, it will not be worth the effort to get it fixed. That's not a disaster on a low priced item.
 
Top Bottom