The Audirect Atom 2 is a compact digital-to-analog converter (DAC) and amplifier combination unit which connects to the transport device via USB-C. The Atom 2 was provided to me for review by ShenzhenAudio, where it is available for purchase for $79.99.
I have used the Audirect Atom 2 with the following headphones:
- Moondrop S8
- Moondrop Variations
- Moondrop Quarks
- SeeAudio Yume
- Nicehck ME80
I have tested these headphones with local FLAC and Spotify Premium. Visit my last.fm page to get an idea of what I listen to:
I did not use the Atom 2 to play any Master Quality Authenticated (MQA) files in my evaluation and will not address MQA in my review other than to say this: I am strongly opposed to MQA and view its inclusion on any device as superfluous if not an outright negative. It is an anti-consumer, objectively inferior medium to lossless Pulse-Code Modulation. Please refer to Archimago’s review of the controversies surrounding MQA or GoldenSound’s video on MQA for deeper dives on the topic.
PACKAGING AND ACCESSORIES:
The Audirect Atom 2 comes in a rectangular deep blue box. The lid of the box is embossed with the Audirect logo, and technical specifications for the Atom 2, as well as Audirect’s corporate contact information, are provided on the rear of the box. The adapter is held in a foam mounting sheet inside the box. In addition to the Atom 2 itself, the box contains a user manual with appropriately brief instructions as well as a reference guide for the Atom 2’s indicator light.
The Atom 2 also comes with a USB-C female to USB-A male adapter. This adapter breaks USB specifications and does not have active circuitry to prevent backpower. I do not recommend using this adapter. If you must use an adapter like this with the Atom 2 or any other USB-C dongle DAC/AMP, I recommend the ones from CableCreation, which does have this important safety feature.
DESIGN, BUILD QUALITY, AND AESTHETICS:
The Audirect Atom 2 has an ultra-compact block-like design. The body of the device is a polished slab of copper-zinc alloy with a chrome red faceplate. The Audirect logo and “ATOM 2” printed in white on the faceplate. The USB-C male connector protrudes straight out of the back of the device, and the single-ended 3.5mm jack is set into one of the side faces. There is an indicator light on the top face of the Atom 2 which displays different colors depending on the sample rate and format of the material being played back. “AUDIRECT CO., LTD.” is etched below the USB-C connector on the transport-facing side of the Atom 2, and the MQA logo appears off to the side of the connector.
The biggest problem with the Atom 2’s design is that its finish is a fingerprint magnet. In addition, the seam between the body and the faceplate accumulated a small amount of grime over the course of my evaluation. One final nitpick I have with the Atom 2 is the inconsistent font choices for different bits of text on the device. The faceplate logo, device name, and company name all use different fonts. It would have been more consistent to use the same font used in the logo for all the text on the device.
The Audirect Atom 2 is powerful enough to drive just about any in-ear monitor. I reach my typical listening volume with my phone’s system volume set to 58% with the hardish-to-drive Moondrop S8. On Windows, I reach the same volume at a system volume setting of 40/100.
POWER CONSUMPTION AND HEAT MANAGEMENT:
The following power consumption measurements were taken while the Audirect Atom 2 was in use:
The Audirect Atom 2’s power consumption while in use is roughly comparable to the Hiby FC3 and Meizu HiFi Pro. The power draw is higher than that of the gold standard for USB-C audio devices, the Apple dongle:
The Atom 2 does have a standby mode that kicks in when the device is plugged in without a connected headphone:
While heat management is adequate for a typical multi-hour listening session, the Atom 2 can get very hot if left playing overnight. It does cool off quickly once playback is discontinued in this scenario.
STANDARDS COMPLIANCE AND FUNCTIONALITY:
The Audirect Atom 2 correctly implements Android’s headset button standards. This means that the Atom 2 registers button presses on the attached analog headset and correctly triggers the appropriate behavior (play/pause, volume-up, volume-down, and voice assistant).
The Atom 2 also correctly sends connector status to the host device. When connected to a USB-C port but not connected to a headset, the Atom 2 is not accessible as an output device. The Atom 2 becomes the active output only when connected to a headset. Disconnecting the headset but leaving the Atom 2 connected to the USB-C port returns audio playback to the previously used audio output.
Both of the Atom 2’s connectors fit snugly and I did not have any issues with playback being discontinued by jostling the connectors in the pocket or otherwise disturbing the transport device.
While the Audirect Atom 2’s sound quality is adequate for portable use, over the course of my evaluation I could not shake the sense that it was slightly inferior in terms of resolution and detail retrieval to my favorite source device, the Hidizs S9. I routinely felt that transient delivery was slightly blunted in comparison. In a volume-matched(<.1 dB), sighted, non-instantaneous switching (1–3 second delay) comparison of the Atom 2 and the S9, this impression held true. There seemed to be slightly less definition to notes and less space around them, and transient delivery seemed slightly less precise. The difference is very small and only evident to me in a quiet home environment with the Moondrop S8, which is by nearly all accounts an incredibly resolving monitor. I discovered in my review of the E1DA 9038S that I could hear the differences between digital filters, and I suspect that is the reason for my perception.
The Audirect Atom 2’s primary differentiating factors are its extremely compact form factor and its laudable standards compliance. In most other respects, it is adequate but not exceptional.
The Audirect Atom 2 can be purchased below: