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

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Hello,
Thanks for your work and precious informations !
I have a HD800, with a very old PPA custom amp ... So I am very interested by this NX4 or the DX3.

I am a little bit in trouble with the numbers of the NX4 : Topping claims a power for the NX4 at 124mWx2 at 300ohms, but if I understand well the measurements above, it is 20mW (it seems at high gain) ? Other measurements seem to be coherent with the Topping numbers, so maybe a bad interpretation from me ?
Topping claims a power for the NX4 at 114mWx2 at 300ohms when thd+n < 1%.
in amirm's measurements, when THD + N = 1%,it is almost 6Vrms , 6V * 6V / 300ohms,it is 120MW。






 
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Hello everyone. Amazing info. Great work Amir. Objective clarity in all of the noise.

So I recently decided to order a Topping D10, Loki Mini, and a JDS Atom to power my new HE4xx headphones because of Amir’s review. Here is my question. If the NX4 is as good or better of a DAC as the D10 and D30, can I use the NX4 as just a pure DAC and still run it thru the Loki and Atom to get the benefit of the Atom’s qualities when it is powering the He4xx’s? Also then I would still get to use the Loki in desktop mode, but the NX4 could be taken portable when I was on the go. Or is it super bad to run a DAC/amp to another amp, or you lose all of the qualities of the Atom? Sorry that is a lot of question, but I think you guys understand what I mean. In short, can the NX4 replace the D10 or a dedicated DAC needed for the Atom to sound its best?
 

amirm

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Or is it super bad to run a DAC/amp to another amp, or you lose all of the qualities of the Atom?
Not at all. Distortion-free amplification is important regardless of how you feed it.
 
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Not at all. Distortion-free amplification is important regardless of how you feed it.
So does that mean that the NX4 can replace the D10 as a DAC even though it is not RCA separated? Do I just keep the volume low on the NX4 so the Atom is doing all of the heavy lifting?
 

amirm

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Yes and no. I don't know if the NX4 DSD works on external power without its batteries. I had trouble with an iFi DAC that way, requiring certain power up sequence for external power which I got tired of following. In other words, if your use is mostly desktop, use a desktop DAC.
 
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Yes and no. I don't know if the NX4 DSD works on external power without its batteries. I had trouble with an iFi DAC that way, requiring certain power up sequence for external power which I got tired of following. In other words, if your use is mostly desktop, use a desktop DAC.
I would say it would be 50/50 desktop/portable. Other things I have read seem to imply that leaving it plugged in for constant desktop use was a thing people do per conversations about how that would effect the battery. So I guess volume low, gain low. The main desktop difference for me will be the ability to use the Loki. For years I had my AudioTechnica D40s and liked them but I wanted to “move up”. I got the HE4xx’s but was immediately disappointed in how much the mids around 500Hz were so dominant that it made everything sound like it was coming out of a tin can.

Once I EQed it in iTunes it fixed it for my ears and the highs and lows were present again and I like the punch of the bass more than my D40s and it just sounds like there is less noise, more music. But EQing with iTunes mobile is preset and other EQing apps don’t work with Apple Music. So I figured I would get a hardware solution for desktop as well as get the Atom so I can get good volume out of the HE4xx’s and better cleaner sound. But if the NX4 can just be used instead of the D10 then it’s two birds one stone. I can have the Loki when desktop and maybe sometimes portable, but most portable situations I could just unplug the NX4 and go. No Loki, but still way better sounding on HE4xx’s than the iPhone can do.
 
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Oh sorry, one last thing. I am wanting a Starbucks headphone that is also a good upgrade from my D40’s (which got stepped on and broken). What is a good “can’t go wrong” closed back headphone to go with my new setup? More V shaped (but still clean and separated like the HE4xx’s) that is under 200? I love soundstage and rarely find highs too high and I prefer punch in bass more than rumble thick bass.

Oh and thank you again for such a quick response. You will save me a lot of time and money. I will hop over to your Patreon to show my appreciation, but I have a feeling whatever money I give you will be felt way shorter than how long I will be benefiting from your advice. So thank you again.
 

flipflop

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Oh sorry, one last thing. I am wanting a Starbucks headphone that is also a good upgrade from my D40’s (which got stepped on and broken). What is a good “can’t go wrong” closed back headphone to go with my new setup? More V shaped (but still clean and separated like the HE4xx’s) that is under 200? I love soundstage and rarely find highs too high and I prefer punch in bass more than rumble thick bass.
Sony MDR-7506 or Beyerdynamic DT 770.
 
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I was thinking about the 770s. Good to know I was headed in the right direction. I listened to the Sony MDR-Z7 and holy cow, the bass was great and the highs were pretty good, but most of the mids and a lot of vocal sounded like it was at the end of a tunnel. Maybe the 7506 is different. I will research both. Thank you.
 

flipflop

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I listened to the Sony MDR-Z7 and holy cow, the bass was great and the highs were pretty good, but most of the mids and a lot of vocal sounded like it was at the end of a tunnel. Maybe the 7506 is different.
MDR-Z7 have a large dip in the 1-2 kHz range, sucking the vocals to the back in the mix. They also have bass bleeding into the mids, further muddying up the vocals.
MDR-7506 have none of these issues. If anything, the vocals might be too forward.
 
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Okay back to the NX4 and getting the its amp to get out of the way of the Atom. So I I’m a software engineer and I can rewire a house or solder a component together, but I am clueless on sound engineering. I’ve noticed that most DACs are measured at 2 volts. Does that means that if I want the NX4 to be putting out only 2 volts on low gain, and is this something that a simple multimeter on the headphone jack while putting the knob on the NX4 at various levels until it is right at 2 volts. Sorry this may be super stupid/your welcome for a good laugh :)
 

dc655321

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Does that means that if I want the NX4 to be putting out only 2 volts on low gain, and is this something that a simple multimeter on the headphone jack while putting the knob on the NX4 at various levels until it is right at 2 volts.
The NX4 has three modes (I think? I've only ever used 1) ):

1) headphone amp and dac - usb AND headphone ports plugged in
2) amp only - IN/Lineout port AND headphone port plugged in
3) dac only - usb AND IN/Lineout ports plugged in

The "charge" usb port is independent of these three modes.

EDIT: just checked this, and 2) and 3) work as above. Note also that mode 3) outputs 2 Vrms and is independent of the volume pot.
 
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Ah okay. I didn’t read enough on the product page to see that there is a true DAC only function. I looked on forums for 2 hours to try to find out but I should have gone straight to the product info on Massdrop which says it right there. Oh well :) When I get them in the mail next week and if it turns out I don’t like the performance of the Loki (or if I am able to be confident that in a digital EQ through an app) and/or if the Atom doesn’t really add much at all beyond the NX4 by itself, I will send back the Loki and Atom and save that money.

I’m hoping that the NX4 is able to be very good enough for portable and that the Atom/Loki will be worth keeping so that I have total control of whatever headphone I’m using. Powering the HE4xx with the phone or Mac, if I put the bass end of the EQ to a good punchy bass level (around +6dB) even with the software preamp (a feature not even on phone apps) set to -6dB to match the increase bass, the power just isn’t there and it gets very distorted. With the phone I can only go up +3dB because there is no software preamp, before it is super distorted. I’m hoping that the power of the NX4 I can do some app based EQing without distortion, and when desktop bound, I can really make the HE4xx’s sound like what I will probably one day find in another headphone without EQing which is ideal obviously.

I know many people won’t care about these thought-stream details, but someone who is shopping from scratch might want to know all of these details to help inform their decision.
 

MrC

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I know you already have the info you needed but just to say that I am currently using an NX4 DSD on my desk at work and I have been using it also as a DAC only into a DSP (BSS) feeding some Meyer speakers with great results. Although my headphones aren't really power hungry (80 Ohm), I never have volume over 60% on low gain, so it is quite powerful for its size.

I have an Atom and a P20 on their way for my desk and will be using the NX4 as the DAC for them until I decide on what desktop version I will replace it with. The NX4 will then be used for portable and travel setups, doing a mighty fine job of it also :)
 
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I know you already have the info you needed but just to say that I am currently using an NX4 DSD on my desk at work and I have been using it also as a DAC only into a DSP (BSS) feeding some Meyer speakers with great results. Although my headphones aren't really power hungry (80 Ohm), I never have volume over 60% on low gain, so it is quite powerful for its size.

I have an Atom and a P20 on their way for my desk and will be using the NX4 as the DAC for them until I decide on what desktop version I will replace it with. The NX4 will then be used for portable and travel setups, doing a mighty fine job of it also :)
I had already ordered the D10 and was considering the D30 when I saw a review from a member here on YouTube talking about how great the D30 was, but that the NX4 from a DAC perspective was equal or even better compared to the D30 which is supposed the be very similar to the D10 concerning sound qualities. I’m not after a DAC for it to raise the highs and bass of my way-too-mid-heavy HE4xx’s in their non-amped state (shoot, they could sound way different once powered properly - though I doubt it - better once amped yes, but not a total different sound signature). But from research it seems that no one says that DACs have a HUGE effect on signature. The HE-4xx is simply not the right headphone for me signature wise. But I know the Loki will fix that because even a bit of tweak with a software EQ and a huge drop on 500K makes me like the HE-4xx a lot, they’re just distorted due to the power need created by EQing.

So I’m not after a DAC for what EQing (Loki) can do. And I’m not after absolute transparency, 99% transparent is good enough. But a EQ can’t add depth or soundstage. I’m hoping a DAC can and the NX4 is supposed to be able to do that.

I used to have a pretty powerful high end Onkyo system (I forget which model - it was 15 years ago). But there was a song that has a part where there is THX effect where the sound builds and builds in a similar sense to THX. When I would play that on my Onkyo, it had such depth and clarity that it would give me chills every time. I have been chasing a headphone solution to get me back there on that song ever since. My Audio Technica D40x’s are fine sound signature wise as-is and EQing only hurts it. But on that song it’s totally lifeless. My HE-4xx’s are much closer to my goal on that song but that is only after EQing, but it is un-amped so it distorts. I’m hoping that with big power from the Atom, better than iPhone DACing with the NX4 and EQing with the Loki, I will be to where I was with the Onkyo, or close at least.

What confuses me is that everyone calls the D40x “neutral” and everyone calls the HE-4xx fairly “neutral”. But to my ears, the D40 sounds great signature wise, and I like V shape. But the HE-4xx sounds extremely inverted U shaped (well at 500K anyway). So even if my ears can determine V vs inverted U, my ears can definitely tell that they are not both “neutral” because they are wildly different. Problems with subjectivity I suppose.
 
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dc655321

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But a EQ can’t add depth or soundstage. I’m hoping a DAC can and the NX4 is supposed to be able to do that.
Re: depth and soundstage.
Those are properties of recordings and how they're rendered by transducers, not electronics. I'm afraid no DAC or amp will help in that regard.
 
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Re: depth and soundstage.
Those are properties of recordings and how they're rendered by transducers, not electronics. I'm afraid no DAC or amp will help in that regard.
Yes, definitely a properly supported headphone/amp combo vs a different amp (equally supporting) of the same headphone will not, but surely a fully powered headphone versus a headphone that is struggling just to get the sounds out without distorting (or even filled with distortion), is going to result in one combo (underpowered) having less depth and stage than the properly powered one. I mean, if I take my headphones and raise the volume on my Mac enough to create crazy distortion, all sonic properties fall in the crapper, but at least it is nice and loud. But no quality is doing well. That is the case right now. The HE-4xx’s have low impedance (35ohms) so they can get loud on anything, but the sensitivity makes that volume poorly supported on 50mW of power so it distorts. So one good amp versus another, sure no soundstage difference. But no amp versus amp? There has got to be better soundstage when you are talking about correcting terrible distortion. Everything will sound better about it. Or am I missing something?
 
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Sorry I didn’t say the sensitivity. The HE-4xx has 35/93. By comparison the HD-800 is 300/102. So even though the HD800 (a headphone known for desperately needing an amp) gets very loud at 15w at 300ohms. So a HD800 on a Mac or iPhone won’t distort but it won’t get loud either. A HE-4xx has the opposite problem. Easy volume on anything, but it needs 150mW for the same volume to be properly supported. And I can hear the problem in obvious mega distortion with even a tiny bit of EQing, considering +3dB on an EQ doubles the needed power to 300mW. My Mac has around a 50mW to work with at 35ohms. So I have got to think that a good amp will improve every sonic quality, including soundstage.
 

dc655321

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That is 93 dB/mW. Good so far...

By comparison the HD-800 is 300/102.
That is 102 dB/V. Different units. To put things in the same dimensions, 102 dB/V is 98 dB/mW for the hd-800.
Not radically different...

The distortion you refer to could be due to current-limiting clipping: 35 Ohm is a more demanding load than 300 Ohm, obviously.

But, assuming for a moment that your source is not current-limited, 50 mW into a 93 dB/mW headphone would yield about 110 dB.
Is that not enough volume?
 
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