In this TOPPING NX7 review, I’m checking out the latest portable headphone amplifier from TOPPING Audio. The NX7 is powerful and features NFCA (Nested Feedback Composite Amplifier) modules, 3 gain modes and a 20-hour battery life. The price is $179.

Disclaimer: This sample was provided by Apos Audio for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.

TOPPING NX7

Package and Accessories

The NX7 arrives in a small black box with the TOPPING logo on the top. Inside the box, you’ll find:

• TOPPING NX7
• 3.5 to 3.5 audio cable
• USB charging cable
• Rubber band
• Rubber pad
• User manual
• Warranty card

Design

The NX7 is CNC machined from an aluminium block. Its dimensions are 135x70x16mm which is roughly the size of an average smartphone. The device has some real heft to it and feels solid in the hand.

On the front panel are (from right to left) the power/volume knob, 3.5mm auxiliary input, 3.5mm headphone out and 4.4mm headphone out. In addition, there are 2 corner guards on the front. These guards protect the panel and headphone plugs as well as help to prevent accidental volume changes in your pocket or bag.

Moving around to the back of the unit, we find (from right to left) the gain switch, power/battery LED and USB-C charging port.

Functionality and Battery Life

Using the NX7 is simple and straightforward. You simply plug into your phone or source using the included auxiliary cable and plug your headphones or earphones into the NX7. Easy!

With up to 180mW of high power under a 300Ω load, the NX7 can easily push full-sized headphones. Not only that but even at high volume, the distortion is extremely low (only 0.00008% at 200mW). TOPPING’s NFCA amplifier circuit has an SNR of 135dB making it one of the cleanest portable amps on the market.

Do you use sensitive IEMs? That’s fine too; the NX7’s output impedance is just <0.1Ω so it won’t add any colouration to the sound. That makes it versatile with every kind of earphone and headphone so sound matching is no longer something you need to worry about.

The battery life is up to 20 hours on low and medium gain and 10 hours on high gain. That should be enough to get you through a full day. However, charging the 4000mAh battery takes up to 4 hours so it’s best to start charging early.

Sound

Sources used for testing include the Soundaware M2Pro and iPhone with the Cayin RU6.

Headphones and earphones used for testing include the Beyerdynamic DT990 Pro, HarmonicDyne Zeus, TRN VX Pro and ItsFit Fusion.

So, how do you begin to describe the sound of something that’s essentially transparent? TOPPING amplifiers and DACs have some of the best measurements in the business when it comes to things like THD+N and SNR. This one basically takes noises and makes them louder.

Well, I’ll start by saying the NX7 has an unbiased sound signature. Each part of the sound spectrum from the bottom to the top gets the same equal treatment. There’s no bias towards the bass, mids or treble – it’s an even playing field. In fact, listening to the NX7 might just reveal traits about your source that you weren’t aware of.

The NX7 gives you details. When something has such absurdly low levels of distortion and a silent noise floor, all the details come through unhindered. There’s no masking or smearing of the signal because everything is so darn clean.

Using my Soundaware M2Pro as the source and listening to Above & Beyond’s “Sun & Moon (acoustic)”, I’m deeply impressed with the balanced and detailed presentation. The focus of the song is on the vocals but the instruments in the background are intricate and layered. Here the NX7 shows its ability to flex its muscles without sacrificing any of the subtleties in the recording.

Picking up the pace with Wheel’s “Hyperion”, the NX7 shows it can deliver the hard-hitting drums with gusto and punch. Not only that but the bass guitar is loaded to the brim with texture. Electric guitars growl and the vocals are detailed and engaging. All the while, the song’s rhythmic percussion is expressed with vigour and precision.

Its soundstage might not be as expansive as some desktop units but it’s far from being small, especially when paired with some good open-back headphones. There’s tons of depth in the stage and the NX7’s imaging and layering are superb.

Verdict

Coming into this review, I knew the TOPPING NX7 would not disappoint. But I was not expecting the degree of pleasure it would give me once I hooked it up to my favourite DAP. If you’re looking for a pure, uncoloured portable amplifier, I can’t think of a better option than the NX7. It has a rugged construction, good battery life and it delivers pure audio bliss.

Head over to Apos Audio to get yours today.