Repairing the Audirect Atom 4 DAC

My beloved Audirect Atom 4 dongle DAC started experiencing intermittent sound in the left channel. Since the earphones worked perfectly with other devices, it was clear that the issue was an internal contact failure. I bought it on AliExpress, so I didn’t expect any official support—I decided to take it apart myself.

Audirect Atom 4: Small, Handy, and Great Sound

To briefly introduce the product, it’s a relatively recent release in Audirect’s Atom series. It features the ESS9280 AC Pro chipset, delivering decent sound quality and a power output of 137mW (@32Ω), which is quite respectable for its size. The fact that it packs both 3.5mm and 4.4mm jacks into such a compact body is a huge plus, making it perfect for convenient use with a smartphone.

A Disappointing Internal Design

The entire housing is secured by just one star screw at the right end, making the disassembly process incredibly easy and the maintenance accessibility excellent. Not that a typical user would ever need to open it, though.

Opening the housing revealed several surprising design choices. While the 3.5mm jack was securely soldered directly to the main PCB (on the right in the photo), the 4.4mm jack—likely due to space constraints—was mounted on a separate daughterboard (on the left) and connected to the main board via five wires. What was even more baffling was the mounting method for the 4.4mm jack: it was fixed to the base solely with hot glue, with no additional support structure. This made it highly vulnerable to the physical stress exerted when plugging or unplugging cables.

Unstable 4.4mm Balanced Jack and Causes of Disconnection

The 4.4mm balanced jack’s 5-pole configuration consists of L+, L-, R+, R-, and Ground. Among the four conductors connecting the daughterboard to the main PCB, the L- line also acts as a physical anchor for the jack, meaning it connects to the opposite side of the board compared to the other four wires. As the hot glue holding the jack lost its grip, the jack began to wobble, putting excessive strain on the anchor point and pushing it to the brink of disconnection. This movement was clearly the cause of the signal issues.

Solving the Problem with Silver Solder and Loctite

Once the problem was identified, the repair was straightforward. Simply patching the existing connection felt like a temporary fix that would eventually fail again, so I removed the loose wires. I then used silver solder to create a robust, direct connection to the PCB.

I also reinforced the physical mounting. I added a drop of Loctite between the wall faces where the 3.5mm and 4.4mm jacks meet to lock them in place mechanically. Now, the jacks are rock solid and won’t wobble easily, even with frequent use.

Final Thoughts

After reassembling the unit, I performed a listening test. Hearing the sound clearly without any dropouts was a huge relief. Even with branded products, sometimes you find design flaws like this when you peek inside. Anyway, my Atom 4 is now firmly reinforced and has officially become a “permanent fixture” in my collection that I can no longer sell. Haha!

🔗 Original Post :
Audirect Atom 4 DAC 소리가 안 들린다면? 4.4 단자 내부 결함 자가 수리 도전기
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