REVIEW: Naim Uniti Atom Headphone Edition

If you asked me which integrated amplifier is the best, it would be a difficult question to answer indeed. But the Naim Uniti Atom is certainly high on the list at its price range. At least if would like streaming and and a small footprint to go with it – it really is unique.

Good as it may be, the regular Uniti Atom does not really shine as a headphone amplifier, even though it does have a 3.5 mm headphone output on the front. I don’t know if anyone has complained about this to Naim, but now finally the British hi-fi manufacturer has chosen to swing the wand and turn the whole construction into a pure headphone amplifier!

 

The Naim Uniti Atom Headphone Edition, which is the full name of the new amplifier, looks like its namesake. Only here the speaker outputs are completely gone, in favor of some hefty headphone outputs in the form of 6.3 mm unbalanced jack, a 4.4 mm balanced PENTACONN connector, and also a balanced 4-pin XLR output on the back.

On the back you will also find two preamplifier outputs, one being unbalanced RCA and the other balanced XLR, in addition to digital inputs. Finally, unlike most other headphone amplifiers, the Uniti Atom HE also has a remote control, meaning it’s a full-fledged preamplifier.

For a complete hi-fi system, an additional power amplifier is needed, such as Naim NAP 200 DR or NAP 250 DR. And, of course, speakers. Or why not, indeed, a pair of active loudspeakers?

The only thing I miss is a USB-DAC input, which could take over as sound card for the PC. That would really be something!

If you have a headphone cable with an XLR connector, connect it to the back of the amplifier. Otherwise you will find analog preamplifier outputs and digital inputs here. But no USB-DAC input. Photo: Naim

Music streaming

If you’re like me and want an amplifier packed with technology, then Naim does not disappoint. There are plenty of built-in streaming options. Roon Ready will be appreciated by many, allowing you to open Roon on your PC or Mac, and stream directly over the home network. In addition, there is both Airplay 2, Chromecast and even Bluetooth with aptX. There’s also direct support for Spotify Connect, Tidal, Qobuz and Internet radio, to name a few.

Connect to the network with either wireless Wi-Fi or wired Ethernet.

The Naim Uniti Atom HE can be operated with the buttons on the front panel. Photo: Naim

Delicate digital stage

Both the streaming platform and the DAC part are the same as in the integrated Uniti Atom. This means, among other things, a SHARC digital processor, which makes as many as 2.7 billion calculations per second using 40-bit “floating point” resolution. This gives many more possible digital values than the so-called “fixed point”, and which together with 16 x oversampling should minimize jitter and remove all annoying frequencies that can give the analog filter in the digital converter an undesirably high working temperature. We are promised that the jitter measurements are the lowest ever measured with these Burr-Brown DAC chips.

Brand new amplifier stage

The amplifier section is what really makes the Atom HE stand out. This is made especially for this amplifier, and can drive headphones with 1.5 watts in 16 ohms. If you are only used to speakers, this may not sound like much, but with headphones you only need milliwatts. It is more than enough power for most headphones, perhaps with the exception of the most infamous planar magnetics (such as the infamous HiFiMAN HE-6).

Naim claims to be using some technologies from the flagship amplifier Statement: Among other things, the Atom Headphone Edition operates in pure Class A until it becomes uncomfortably loud, after which it switches to AB.

 

Ease of use

Connecting the amplifier for the first time is really easy: Hold the remote control next to the amplifier and press the Home button to pair. Select language, download the Naim app and connect the product to the wi-fi network from there. Select Uniti Atom HE in the app, and the network setup starts. Ethernet cable is, of course, the simplest and most stable. Select a name for the amplifier, such as Office or Music room, or just keep the amplifier name.

When done, enter your user data in your Tidal or Qobuz account in the Naim app to stream from there. Or just open the app you normally use, and stream to the amplifier via Chromecast or Airplay.

The Naim app has a pleasant user interface, and I personally like that my favorite music is on the front page, regardless of whether it is taken from Tidal, Qobuz – or both. But to be honest, I almost always use Airplay or Chromecast from my mobile, while the PC and Mac usually play from Roon. Which makes the most out of high-resolution music files.

Same cooling fins as on the integrated Uniti Atom. Photo: Naim

Dreamy headphone sound

Uniti Atom HE is perhaps the world’s coolest headphone amplifier with built-in streaming – so how does it sound? Well, to say that it sounds good or great would be a big understatement. It sounds eminently good! Especially with balanced cable, then you just have to remember to press the headphone button in the upper left corner on the front. Otherwise no sound will come.

Sennheiser HD 800S

Sennheiser HD 800S are fantastic headphones, but they are not exactly known for their warm sound. On the contrary, they are analytical but without getting boring, with a slightly slimmer bass than some listeners might prefer. But they also have a wonderfully large and open soundscape. Perhaps the largest among any headphones in its class. The combination places these among the world’s best headphones, in my ears.

Uniti Atom HE brings out all the qualities I love about the HD 800S. The super tight, though not the fullest bass, the extreme dynamics – and with a tonality and resolution few can dream of. Its touch of warmth in the midrange area is a very nice bonus.

Billie Eilish’s voice glows on the ballad Your Power, the vocal cords tickle the ears ever so softly. There’s a lot of air, but the details at the top are never thrown at me. They are presented in a restrained albeit clear manner.

In comparison, you will hear even more air and details coming from Sennheiser’s own amplifier HDV 820, but it is also presents the bass region in a slimmer manner.

The bold and fully analog Auralic Taurus, for the occasion connected to a simple and affordable – but neutral and good – Grace Design Standard DAC Balanced, sounds in turn more muscular and even fuller in the lower midrange and down in the bass are. I have always thought this is the perfect match with the HD 800S. And the combo is really good. But even though the Naim amplifier may not have exactly the same fullness in the bass, it delivers the transients significantly quicker. It also has a better defined and larger soundstage, and the details come more naturally against a blacker background.

Hard-hitting rock and pop bring out the same differences, and I actually feel that the HD 800S sounds more entertaining with hard drums through the Naim amplifier compared to the Taurus, and especially when compared to the HDV 820. The music played through the Naim amplifier gives me greater peace inside, if you will.

Focal Clear MG

Focal Clear MG are also a very good pair of headphones, and with these, the Naim amplifier will come into its own even more. With Avenue Beats’ hip-hop banger F2020 Remix the snare drum sounds realistic, with a nice body and bottom end. With the Sennheiser amplifier, this one sounds significantly thinner, while the Taurus in turn has a warmer and fuller bass. The kick drum sounds even bigger with Taurus than with Naim, but at the same time it sounds as if the drum skin is a little looser. Naim is faster, especially in the middle bass. The Naim amplifier also has plenty of power surplus, just not quite as wild as the Auralic Taurus. It is, nonetheless, powerful enough to make the Clear MG headphones bottom out if you push them too hard playing very bassy music. To most people’s ears it might be very loud, but to mine just right…

Drop / HiFiMAN HE-4XX

In collaboration with the powerbuy website Drop, HiFiMAN has created the HE-4XX, a sort of improved version of the HE-400i. The HE-4XX is quite affordable, but very good. But also a very heavy load. The Taurus has a higher gain and can therefore drive these even louder than the Naim Uniti Atom HE. But I’m more than content when I crank up the Naim amplifier. Which also sounds better than the Auralic Taurus. On some vocals, Auralic triggers a slight sharpness in these headphones that I don’t really care for, while the Naim amplifier presents the sound more naturally.

Atom Headphone Edition as a preamp

I have only managed to test the Naim amplifier in shorter sessions as a preamplifier. But you do not have to listen for long to realize that it is really good. Together with the power amplifier Hegel H20, it presents the sound with a warmer glow in the midrange than with Hegel’s own P30, which I in turn experience to have a slightly broader soundstage. But Atom HE sounds really good, and also has enough gain to work well with the low sensitivity but otherwise excellent amp EAM Lab Studio 362.

Naim Uniti Atom HE: Conclusion

The Naim Uniti Atom Headphone Edition may seem like a strange product to some. Naim has taken the multi-talented Uniti Atom, removed the speaker outputs and thus made it a much more market specific product. But if you listen a lot to headphones – or need a capable preamplifier – then this is one of the coolest products we can think of.

Uniti Atom HE forces power and speed out of even the toughest headphones, and with just enough warmth in the midrange, it makes already good headphones sound magical. The amp has plenty of power, and you’ll have to look hard to find headphones it can’t drive.

Naim Uniti ATom HE also excels as a preamplifier. There are certainly better dedicated preamps out there at the price point, but the magic it gives off through headphones is also reflected through a hi-fi system. No one can really ask for more. I don’t know of a more complete preamplifier / headphone amplifier / network player at this price. It’s simply a must-hear!