"Absolute Beast": Passion for Sound Reviews the TOPPING NX7 Portable Amp

Note: This article is based upon the video "Topping NX7 Portable Amp Review - Perfection in your pocket! (sort of)” made by Passion For Sound on their YouTube channel and is printed here in partnership with Passion For Sound. The review was originally posted on April 5th, 2022. Edits have been made for clarity and length. You can buy the TOPPING NX7 on Apos Audio

Intro

Hey, folks. Welcome to another Passion for Sound audio review. A little while back, I posted on the community page here on YouTube and asked who would be interested in a review of the TOPPING NX7. It had been just announced as a new product, and many of your commented on that post and said you’d be interested in a review of it because it’s a good option for, say, a desktop system at work, where you don’t want to take up a lot of space, or if you want to drive larger headphones while wandering around the house, or maybe you need a true portable stack. That’s what the NX7 is designed for, and many of you said that you were interested. So here we are. Let’s take a look at the TOPPING NX7.

Power Outputs

The NX7 will deliver 1.4 watts of power into 32Ω, or 180 milliwatts into 300Ω, and obviously everything in between. 

The gain control is one of the areas where the NX7 is quite good. It gives you the ability to run a -14dB gain at basically a 0dB gain, and a +14dB gain. 

Basically, in the end, all we need to know is that you’ve got plenty of range from the most sensitive of IEMs all the way through to difficult high impedance headphones. If you’re wondering about low impedance planars, they’re completely fine as well. They’re going to run mostly in medium gain.

Design

There is a power light–just a very discreet one–on the back panel. It tells you when the unit’s on and also when the battery is getting low and when the device is charging. It’s a very simple device in general, but, while we’re talking about the design, I’ve already mentioned that it’s a full metal case, and that’s great. It feels really good and solid in the hand. I should also mention that it comes with a couple of rubber bands and also a rubber pad to protect whatever you’re sandwiching it with. 

At this point, I think the NX7 is a lovely device. It’s well-made, by the feel of it. I love the gain control. It gives you lots of flexibility and versatility. The inputs and outputs are all that you need–in fact, more than you need, because that 4.4mil does make it convenient to connect anything that’s got that balanced input without having to use adapters. 

As I said before, it’s not a balanced amplifier, but it’s just nice and convenient. My only real gripe is these side guards, and some people are gonna love them. 


Sound Quality 

I’ve listened to and reviewed a whole bunch of amps over the years that use the same sort of technology that’s built into the NX7. It’s TOPPING’s own version of what’s basically the THX technology, which is a nested feedback approach to essentially reduce distortion numbers.Sometimes the approach results in beautiful sound, and sometimes it results in a kind of flat and lifeless sound. The good news is that the NX7 results in beautiful sound.

It’s a wonderful-sounding portable amp. The sound is clean and neutral without the sterility or artificiality that some of these designs can have. In fact, as I listened to it in isolation, the only criticism I could level at it is that, like so many other amps with this type of design, it just lacks sound stage depth. Everything’s very left and very right, but it doesn’t feel congested or overly flat. It’s only when you start thinking about depth that you notice it’s missing.

For the most part, it is an engaging, enjoyable listen that’s wonderfully neutral and clean but still has a sense of smoothness and an organic nature to the sound that’s very enjoyable because it is so neutral and clean.

I’m not going to bother going into depth about what it does in isolation. It basically just presents the music–only louder. The sound stage width is good. The image separation is good. The instrument tonality–because it’s quite neutral but not artificial–is also very good. The only thing lacking, as I said, is a bit of sound stage depth.

Vs SMSL SH-6

For all my listening tests, I was using the Hugo TT2 as my DAC–so feeding the best quality DAC that I have to these and giving them the best chance to perform. For these tests, I was using the Meze Elite Headphones–again, the best possible headphone I could put in so that I was hearing everything that both amps had to offer.

What I heard when switching between the NX7 and the SH6 was that the SH6 brought everything closer to me. It was still an enjoyable sound overall, but it brought everything in. It did feel a little bit more compressed overall. The sound stage was smaller, less expansive. It wasn’t a bad listen, but the NX7 definitely had the edge in terms of spaciousness and neutrality.

The SH-6 comes across with a hint of warmth when compared to the NX7, and, as a result, the NX7 comes across as more resolving and more detailing, while still sounding very neutral and organic. If we boil it down to purely which one is most enjoyable and natural to listen to, I think the NX7 wins quite comfortably.

The SH-6 is a lovely amp, but it doesn’t sound like it’s got quite the same chops as the NX7 does, and that sort of surprised me. Normally, I’m used to finding desktop devices comfortably outperforming portable ones, but on this occasion it’s the NX7 that I would choose personally. If you gave me each of these as a choice and let me listen to either, I’d be reaching for the NX7.

Obviously, we need to take into account things like the fact that the SH-6 has a pre-amp ability. It’s also a desktop unit, so it’s got full-sized RCA connections. It’s got a full-sized 6.3mil connection, too. So it’s got benefits. I’m not for a second suggesting it’s a bad product, and I’ll be reviewing it very soon to give you all the details. I’m not saying it’s bad, but I was really impressed with the NX7. For an extra $50, it really stacks up from a performance point of view. It’s not just a trade-off where you’re spending more to get a small form factor. You’re getting more to get excellent sound, as well.

Vs TOPPING L50 

My next comparison is with the TOPPING L50. If you’ve seen my review of the L50 and E50 stack, you know that I absolutely adore the E50 DAC, but I wasn’t entirely sold on the L50. It’s a good solid amp for the price, but it’s nothing special. It’s another example of the same nested feedback technology that’s in the NX7, but the L50, in my mind, is a mediocre implementation of it. Having said that, I was really interested to see whether a portable amp would be better than a desktop amp. 

What I heard on the NX7 was a sound that was a little bit edgy, a little bit less refined, perhaps, than the L50. Things like cymbals were just a bit more aggressive, a bit splashier, a bit messier, in some ways. I flipped over to the L50 and things sounded quite polished, quite refined, and you might think that’s me saying that the L50 is better, but in reality the track I was listening to is meant to be a bit messy, a bit edgy and grunge, and that’s what the NX7 was giving me.

The L50 was giving me a bit of a lifeless rendition, whereas the NX7 was giving me all of the energy and passion of the musicians.

The sound from the L50 was probably a little bit fuller overall. The bass might have had a bit more behind it. The overall mid-range weight might have been a bit stronger, but strangely, on the flip side, everything felt less present. It’s like the sound was more distant, and I don’t mean that in a sound stage sense. I mean it was a bit lifeless, a bit ethereal. It just lacked the realness that I wanted.

In the NX7, the music had energy and life and spirit to it. From the L50, the music was just bland and flat and boring–not dreadful to listen to, it was just too polite. In fact, as I’m saying this now–this wasn’t in my notes–I think what’s probably going on is that the ability of the NX7 to produce a better, cleaner, more attacking leading edge without ever getting harsh or edgy or gritty or grainy–unless it’s in the music–brings the music to life. Having accurate leading notes and edges and a good sense of attack is where it stands out.

The L50, on the other hand, smooths it all out a little bit too much. And it’s not that the L50 is a smooth or overly warm and rich amp, it just doesn’t have the leading edge clarity that I believe the NX7 does.

Conclusion

The NX7 is an absolute beast. It’s driven everything from sensitive IEMs with no issues at all to difficult-to-drive planars. So if you do happen to be someone that still needs a portable style amplifier like the NX7, I can highly recommend this. It’s an absolutely brilliant piece of equipment. It sounds great across the board with everything. It’s engaging, enjoyable, and incredibly versatile.

As I said earlier, my only knocks against it are that it doesn’t give you a great deal of sound stage depth–but most amps like this won’t–and the side guards also do annoy me a little. Once I’ve stacked the NX7 with something, none of these issues are deal breakers. Once you have it plugged in and you’re just listening to the music and not worrying about the finer details that I might think about as a reviewer, it’s incredibly fun.