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

[RayDunzl]

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.

You're not going to measure the DAC3 balanced outputs?

 

[amirm]

You're not going to measure the DAC3 balanced outputs?

He was asking about balanced headphone output which has a 2.5 mm four segment connection. Not the normal balanced line output of the DAC (which these don't have).

 

[RayDunzl]

My mistake...

Carry on.

 

[Jimster480]

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.

Well supposedly you can mail it back to them and they will fix it. I haven't had any of my Topping stuff break (thank God) so I don't have the insight into that process. But I can tell you the support is very responsive and they are overall very nice and even the support can get technical.

 

[amirm]

China stuff at least to west coast of US often takes a less time than their estimates. But yes, it is a shame it is not stocked in US with prime shipping.

 

[Guermantes]

Nice to see the NX4 measures well as an amplifier as I've had my eye on the Topping NX5 to pair with my audio player. Hopefully it is even better.

 

[mindbomb]

On the first few tests where there isn't a load mentioned, does that mean the test was done on the line out or the headphone out? If line out, does this mean the gain switch and volume control affect the line out voltage? Also, the frequency response showing the drooping is on the line out with no load?

 

[amirm]

On the first few tests where there isn't a load mentioned, does that mean the test was done on the line out or the headphone out?

The combo THD graph was with loads ranging from 300 ohms down to 33.

Labeling them is tedious so I didn't.

 

[dc655321]

On the first few tests where there isn't a load mentioned, does that mean the test was done on the line out or the headphone out? If line out, does this mean the gain switch and volume control affect the line out voltage? Also, the frequency response showing the drooping is on the line out with no load?

I believe the review states that the headphone out was used for all measurements as being representative of the biggest use-case.

I have not used the line out, but it's my understanding that if the usb port and the line-out are occupied but the headphone out is not occupied, then the gain and volume have no effect. Could be wrong though...

 

[dc655321]

Measured output power as indicated on the graph is about half of what Topping specs I think.

@amirm, I think your measurements are almost spot on what Topping have included in their specs (57 mW @ 300 Ohms, 150 mW @ 32 Ohms).
I believe they have an "off-by-2" error in their listings (counting the sum of both channels).

Was also curious: are you set up to perform cross-talk measurements?
I feel that this is an important performance parameter, and is often overlooked.

 

[mindbomb]

@amirm
so was the frequency response measurement done with 32 ohm load? If the low frequency roll off is from output capacitors, I'm wondering if that will get better with use of higher impedance headphones.

 

[zenmastering]

Yep, that's how the line-out works. There's one plugged in to my mastering console and the internal level control is disabled in line-out mode. I have the NX4DSD and the D50. In comparison, the slightly softer top-end of the NX4 seems to be explained by Amir's test results.

I believe the review states that the headphone out was used for all measurements as being representative of the biggest use-case.

I have not used the line out, but it's my understanding that if the usb port and the line-out are occupied but the headphone out is not occupied, then the gain and volume have no effect. Could be wrong though...

 

[amirm]

@amirm, I think your measurements are almost spot on what Topping have included in their specs (57 mW @ 300 Ohms, 150 mW @ 32 Ohms).
I believe they have an "off-by-2" error in their listings (counting the sum of both channels).

Great. Nice to see them advertise correct spec.

Was also curious: are you set up to perform cross-talk measurements?
I feel that this is an important performance parameter, and is often overlooked.

Yes. When I get a chance I will run it. I am still doing these tests manually rather than automating them. With the later, I should be able to run all the tests easily.

 

[amirm]

@amirm
so was the frequency response measurement done with 32 ohm load? If the low frequency roll off is from output capacitors, I'm wondering if that will get better with use of higher impedance headphones.

If you had asked me yesterday, I would have remembers the answer. But today I have already forgotten. If I get a chance I will re-run with different loads.

 

[vito45]

Thanks for review, I will order NX4 sometime in this week.

 

[amirm]

Keep us posted on how you like it. I see reports that some may have more channel imbalance than the one I tested.

 

[amirm]

Just tested frequency response at 100 kohm load and 33 ohm:

As you see, the overall response does not change.

 

[amirm]

And here is the effect of bass boost:

It is quite aggressive as frequencies get low. And it extends pretty far to 1 kHz.

 

[dc655321]

And here is the effect of bass boost:

View attachment 13252

It is quite aggressive as frequencies get low. And it extends pretty far to 1 kHz.

That plot is a bit more aggressive than Topping's literature by about 1-2 dB. Interesting...

 

[chungjun]

With Michael coming this week, measuring the Benchmark DAC3 will be a priority.

Looking forward!