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

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#41
@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.
Well, that is unfortunate, as that would mean their A30 amp is way less powerful than advertised. I was considering buying it, but now it is a bit anemic for my use case. That, coupled with the output impedance, it doesn't look that appealing anymore.
 
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#42
NX4 DSD looks good. @amirm will it be possible to get the frequency and THD responses of the line out? I saw someone say on Youtube that the line out is better than the headphone out, so that might be interesting.
 

dc655321

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#44
Well, that is unfortunate, as that would mean their A30 amp is way less powerful than advertised. I was considering buying it, but now it is a bit anemic for my use case. That, coupled with the output impedance, it doesn't look that appealing anymore.
Even if Topping's A30 power specs are 1/2 of what is stated on their site, that is still 775mW @ 32 Ohms and 70mW @ 600 Ohms.
What headphones do you think that is inadequate for?
 
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#45
Even if Topping's A30 power specs are 1/2 of what is stated on their site, that is still 775mW @ 32 Ohms and 70mW @ 600 Ohms.
What headphones do you think that is inadequate for?
Hi, I was looking for an amp for HE4XX. They need about 500mW @ 49 ohms for 115 dB. At your given values, this satisfy that. Even O2 has that much power, with decent output impedance to boot. Problem is that I was looking for something with a bit more overhead (could be useful for a bit of bass boosting, when needed).
 

dc655321

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#47
I was looking for an amp for HE4XX. They need about 500mW @ 49 ohms for 115 dB. At your given values, this satisfy that. Even O2 has that much power, with decent output impedance to boot. Problem is that I was looking for something with a bit more overhead (could be useful for a bit of bass boosting, when needed).
Yes, by my wholly inept arithmetic skills, 477mW will get you 115 dB with the HE4xx (info from here).
I agree it's nice to have that level of headroom available - say, listening at 90dB average volume, having 25dB of headroom is a good thing.
I just hope you're not listening at 115dB average SPL! At that level, you'll be needing even stronger amps before long ;-)

As to the output impedance of the A30, you should be fine pairing that with the HE4xx, as they have a flat impedance curve. You will just be loosing a dB or two of volume at all frequencies. Just nudge the volume up. Slightly.
 
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#49
Have you actually tried even 100dB on any headphone or earphone for say 5mins, just for starters ??
Oh, no. My average 'loud' listening volume is around 75 dB to 80 dB (with closed-backs, I guess it could be a bit higher with open-backs). I have measured it before (though, not properly enough). I was just talking about the transient peaks. I listen to a lot of classical music from various countries, with different musical styles and instruments. The dynamic range of a lot of them is high. So I was considering 115 dB taking those into consideration.

It is true that small distortions in transient peaks may not be really noticeable, and depending on my listening volume, it might not even hit that. I have been satisfied listening to portables that drive my headphones to around 107 dB. I was just looking for something that is transparent and clean and also gives me some overhead. Looking at the performance of the rest of the Topping gear, I was interested in A30.
 
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#50
I am not saying A30s output is not enough. 1.5W @ 32 ohms just looked impressive. (Sort of worst-case-scenario-proof).

On the other hand, NX4 DSD is looking better and better. It is the cheapest 9038 DAC/Amp and it is portable. And now it measures well. If the line out is even better (considering how the low-gain measurements look promising), this could replace my DAC (just getting rid of one more piece of equipment from my table sounds wonderful). If the UDA38Pro I was considering doesn't pan out, I will end up getting this.
 

bakker_be

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#51
Oh, no. My average 'loud' listening volume is around 75 dB to 80 dB (with closed-backs, I guess it could be a bit higher with open-backs). I have measured it before (though, not properly enough). I was just talking about the transient peaks. I listen to a lot of classical music from various countries, with different musical styles and instruments. The dynamic range of a lot of them is high. So I was considering 115 dB taking those into consideration.

It is true that small distortions in transient peaks may not be really noticeable, and depending on my listening volume, it might not even hit that. I have been satisfied listening to portables that drive my headphones to around 107 dB. I was just looking for something that is transparent and clean and also gives me some overhead. Looking at the performance of the rest of the Topping gear, I was interested in A30.
35-40 dB transient peaks? That seems a lot, even on classical music ...
 

maxxevv

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#52
At a similar price point, you could consider a look at the Breeze Audio's (so called) HA5000 based headphone amplifier.
Its a discrete amp, and plenty of power. Very low, sub-1 Ohm output impedance value too.

But to be upfront, I have not heard it myself, just some anecdotal reviews and the specs sheet.
 

maxxevv

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#53
35-40 dB transient peaks? That seems a lot, even on classical music ...
Some headphones such as the HD800 and the HD650 do have transient impedance peaks that are like 125% and 80% above its rated impedance values though.
 
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#54
At a similar price point, you could consider a look at the Breeze Audio's (so called) HA5000 based headphone amplifier.
Its a discrete amp, and plenty of power. Very low, sub-1 Ohm output impedance value too.

But to be upfront, I have not heard it myself, just some anecdotal reviews and the specs sheet.
I am also considering that. But the problem is the lack of information (and to some extent, the physical size of the unit. Still, at least it won't slip around). My interest in A30 is due to the good measurements of the rest of their gear.
 
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#55
35-40 dB transient peaks? That seems a lot, even on classical music ...
30 dB is easily possible, maybe 40 dB is a bit much. I had previously observed sounds (background vocals) dipping below -40 dB from listening volumes. I guess decay of instruments will go even lower, though I haven't measured that. I haven't measured peaks properly either.
 

bakker_be

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#56
30 dB is easily possible, maybe 40 dB is a bit much. I had previously observed sounds (background vocals) dipping below -40 dB from listening volumes. I guess decay of instruments will go even lower, though I haven't measured that. I haven't measured peaks properly either.
I think that, in my listening environment, I wouldn't be able to hear that low, especially not with my extremely open Focal Elear, which by the way sound quite well with the A30 :)
 
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#57
I think that, in my listening environment, I wouldn't be able to hear that low, especially not with my extremely open Focal Elear, which by the way sound quite well with the A30 :)
My room, under best circumstances, has about 20-30 dB ambient noise. But, I wasn't talking about that. I was talking about the levels I measured while mixing some traditional folk music. There, the artists stood in groups at different distances from the recording base (they had trouble selecting perfect conditions for recording, perfectly calm night without wind, away from city noises, etc.). Still had trouble during mixing :D
 
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#58
Even if Topping's A30 power specs are 1/2 of what is stated on their site, that is still 775mW @ 32 Ohms and 70mW @ 600 Ohms.
What headphones do you think that is inadequate for?
First, to all, I'm sorry for going off-topic, but I promise this is the last time.

I saw a guy post in head-fi that he measured the output of A30 with a multimeter and 150-ohm pure-resistive load and got 10.5V at high gain (at peak distortion, I guess). So, it seems like Topping posted the correct values for A30. I looked for this as the 26.6Vpp Topping posted in specs kept bugging me, as that would only be possible with output power close to the rated ones.

Things became clearer when I looked at the specs again and noticed that they are rating the power at 1% THD+N. Even @amirm's graph is showing around 3.1V @ 33 ohms @ 1% THD+N, which is near the 293 mW @ 32 ohms that they were advertising. Massdrop quotes the proper specs in their NX4 DSD page, which is strikingly similar to the results here. For A30, Topping's website gives the proper ratings, but for NX4 DSD, their advertising department seems to have messed up the values. So, in conclusion, I didn't read all the sources clearly enough before starting my rant :D
 

DuxServit

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#59
Hi Amir,

Thank you for a great review. I have been looking for such a portable amp/DAC for a while, so this review is timely. Definitely on my to-buy list.

The thread over at HF mentioned a new more expensive version to come out (NX4S ?) so perhaps it’s a good time to get one of these NX4. I’m always weary when audio companies try to “improve” things with an “S” version :)
 

dc655321

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#60
Hi Amir,

Thank you for a great review. I have been looking for such a portable amp/DAC for a while, so this review is timely. Definitely on my to-buy list.

The thread over at HF mentioned a new more expensive version to come out (NX4S ?) so perhaps it’s a good time to get one of these NX4. I’m always weary when audio companies try to “improve” things with an “S” version :)
Are you talking about this post? From November 2017?
 
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