Small size, high-res audio format support, and transparent sound make this wee dongle a winner.
I should have requested the Apple lightning variant of the Audirect Atom 2. Seriously. By ordering (what I, in a fit of delusion, thought would be) the more flexible USB-c version, I’ve pretty much undone one of the most compelling reasons to buy the Atom 2.
- Excellent form factor and build quality
- Supports all high-resolution music file formats
- Clear and transparent sound
- Neat little multi-color indicator LED
- Reasonably priced
- Relatively low power output designed for 32Ohm headphones and IEMs
- Only 3.5mm single-ended output
- Not a dramatic audible improvement over the basic Apple 3.5mm dongle
The Atom 2 is a very small and impressively attractive portable DAC/amp that elegantly plugs directly into the phone of your choice, Android or Apple. Or doesn’t, if you happen to have ordered the wrong one. If like me, you are trying to plug the USB-c version into your lightning port, you are rudely introduced into the great kludge that is converting lightning to USB.
“But why not a short OTG cable,” you ask? It should be that simple. But it isn’t. I’ve bought quite a few lightning to USB-c/mini/micro cables, and they all seem to work only sometimes when the moon and the color yellow align with a particularly smug sheep in Scotland.
So, Apple Camera Kit + USB A to USB-c adapter to the rescue. Kludge power activated!
Ok, so having solved the puzzle of getting it to work reliably, now we can talk about some of the other interesting aspects of the Atom 2. The ±1-inch-long metal-clad form factor makes it stand out in what is now a VERY crowded field of affordable portable DAC/amps.
While in online forums, “donglemadness” rages, I’ve been largely avoiding it. This recent obsession by portable audio enthusiasts and Chi-Fi manufacturers in producing and consuming a countless number of inexpensive DAC/amp dongles has reached a fever pitch.
The original high-quality, aftermarket dongles, the Audioquest Dragonflies, are widely scorned by the donglemadness enthusiasts. Too expensive! No balanced output! Not enough power! No MQA support! No 32bit/768kHz playback! We want it all!
I’m finding it difficult to get too caught up in the mania. These small devices share many similarities (both positives and limitations), like DAC chip, size, shape, price range, and power output. It takes a lot to stand out.
Only slightly larger than the excellent ddHIFI TC28i lightning to USB-c adapter, and sharing the same physical format, the Atom 2 manages to be fairly unique in the portable DAC/amp market. Well done, from a design point of view.
The Atom 2 sports a premium ES9281AC DAC chip and is capable of MQA decoding, 32-Bit/768kHz PCM, and DSD512 playback. Jinkies! Priced significantly under $100? Ok. Wow!
Much like the iFi Diablo, the Atom 2 also sports an absolutely UNBELIEVABLE 5 Watts of power! Well, no. I made that up. It’s unbelievable because it isn’t remotely true. The small form factor, paired with no internal battery, means that output power is bound to be limited—the amplification power peaks at ≥62mW@32Ω, with only ≥30mW@16Ω, and a measly ≥7mW@600Ω.
As a result, don’t even think about pairing the Atom 2 with less efficient full-sized cans. It’s clearly not meant to do so. While my compact car can’t pull a travel trailer, it doesn’t make it any less of a good car. We need to judge things by their intended usage.
So, let’s investigate the Atom 2 together, with limitations firmly in mind, and see if it’s a worthy upgrade from your included Apple (or Android) 3.5mm dongle. That’s what it’s meant to replace, after all.
Audirect, or HiliDAC (HiFi Improved Lossless Incredible DAC) as they are also known, is a manufacturer of electronics including high-definition video players, wireless sensors, and portable audio products, including the popular Beam 2. They are located in Shenzhen, China.
Their current lineup is what they consider their “second-generation DAC products.” They claim five years of experience and the company evolved to fill the void created by the removal of the “3.5 headphone jack, so we focus on portable DAC, attached to the phone as a turntable.”
- Form: Portable DAC/amp
- DAC Chip: ES9281AC
- MQA Support: Yes
- Format Support: PCM up to 32-Bit/768kHz, DSD512 decoding
- Output power: ≥30mW(16Ω), ≥62mW(32Ω), ≥7mW(600Ω)
- SNR: 118dB
- Frequency Response (Hz): 0.032dB@20Hz-40kHz
- THD+N: 0.0004%
- Removable Cable: N
- Output: 3.5mm single-ended
- Weight: 18g
- Dimensions: 28mmx14mmx11mm (LxWxH)
Little dongle. Little black box. The embossed “audirect” logo is not quite centered on the top, and the specifications are listed on a decal on the bottom. Slide off the top, and the Atom 2 is nestled in laser-cut black foam, with a second sheet of foam below holding the USB-c to USB-a adapter.
In the box
- Audirect Atom 2
- USB-c to USB-a adapter
- Basic instruction manual
Want or need a detailed instruction manual? Tough. A list of the LED indicator colors is basically all you get.
The dark anodized shiny metal casing (copper-zinc alloy) is very high-end looking but unsurprisingly is an absolute fingerprint magnet. The 3.5mm jack is offset on the rightmost end, and the tiny LED indicator is on the top left. The front plate is made of shiny red metal, and the Audirect and Atom 2 logos are printed in white on the front surface. The MQA logo is subtly printed on the side that plugs into the phone.
There are two versions available, one with an Apple lightning connector and one with USB-c.
The Atom 2 is a fairly weighty (18g) little piece of audio jewelry. It looks and feels great.
LED active bitrate indicator
The specs of the ES9281AC DAC chipset are pretty darn impressive. The Atom 2 can decode and playback basically any high-resolution audio format up to 32/768, 512 DSD, and MQA. The Atom 2 is rated for ultra-low distortion (0.0004%) and a high SNR (118 dB). It also boasts a dedicated crystal oscillator to reduce jitter for higher quality sound output.
MQA certification is a controversial topic these days, but the concern about paying extra for certification is pretty much moot when a sub-$100 product can include licensed MQA rendering. Rest assured, the Atom 2 is fully compatible with MQA files, regardless of your personal stance on the issue.
Audirect Atom 2 Sound
Paired with a reasonably efficient pair of IEMs such as the IKKO OH10 Obsidian or the Thieaudio Monarch, the Atom 2 provides an entirely enjoyable listening experience. It’s clear, free of background noise or hiss, and delivers enough low-end power to sound vibrant and dynamic at reasonable listening levels.
It’s a bit silly to pair the Atom 2 with a pair of headphones or IEMs that are far beyond its price range, so I conducted most of my listening with the new gold colorway 1MORE Triple Driver over-ear headphones. These sub-$200 headphones have a rated impedance of 32 Ohms and a sensitivity of 104.dB. Their rated maximum power is 50mW. (Full review coming soon).
I figured this would provide an optimal match for the Atom 2’s ≥62mW@32Ω power output rating. And frankly, I wasn’t disappointed. For less than $250 total you can have a whole lot of high-quality audio fun.
I’ve had the HELM DB12 AAAMP Portable in-line headphone amplifier hanging out for a while now, waiting for a proper reason for use. It uses THX-certified amplification and is designed to be ultra-clean with low distortion. The DB12 has an internal battery, a +6dB bass boost switch, and is rated at 111mW@32Ohms. It also adds in-line volume control and play/pause buttons.
The low output power of the Atom 2 proved to be a good foundation for the DB12.
While you do have to pay attention to volume levels upon connection, and there are some loud unwanted clicks if you’ve already got the headphones on your ears when you plug it in, the overall listening experience is somewhat improved, mainly for higher volume listening. The bass boost of the DB12 can be excessive at times but is fun if you are in the mood for some brain-shaking low-end.
But the Atom 2 alone proved sufficient for everyday listening with the Triple Driver headphones. The sonic signature leans towards a slightly warm, lower-midrange, upper-bass boosted sound that may help add a bit of body to thinner sounding IEMs or headphones. It’s pretty darn subtle, though, and for the most part, you just get the impression of clear sound reproduction.
Where to Buy
If for one reason or another, you are dissatisfied with the basic Apple (or Android) dongle that came with your device, or if you are looking for the ultimate in high-resolution file support capability, you could do far worse than giving the Audirect Atom 2 a serious look. If properly paired, it functions as an almost invisible link in your portable audio chain.
No, it’s not going to have the power to drive anything but efficient and sensitive IEMs and headphones properly. Luckily that is a pretty minor limitation these days, as there are many great options that pair perfectly with the 32Ohm requirements of the Atom 2.
If you really need to drive less efficient headphones on the go, there are other all-in-one DAC/amplifier dongle options that essentially do the same thing but with greater output power. Keep in mind though, that these other options offer their own unique set of compromises, including sound quality, battery drain, form factor, etc.
The Atom 2 is inexpensive, built well, attractive, and decent sounding. Furthermore, it’s tiny, plays most anything, and is dead simple to use. All around, a win in my book.