My Audirect Atom 4 dongle DAC began cutting out in the left channel. The earphones worked normally with other sources, pointing to a contact problem inside the DAC. Since I’d bought it on AliExpress and wasn’t expecting official support, I decided to open it up.
Audirect Atom 4: Compact and Convenient
This relatively recent addition to the Atom range uses an ESS9280 AC Pro chipset. It sounds good and delivers 137mW (@32Ω), respectable output for such a small device. Having both 3.5mm and 4.4mm sockets in that compact body is particularly handy when using a phone.
A Disappointing Internal Design
A single star screw at the right end holds the housing together. That makes it easy to open for maintenance, although most owners would never have a reason to do so.
Inside, the arrangement was less reassuring than the easy access. The 3.5mm socket is securely connected to the main PCB on the right of the photo. The 4.4mm socket sits on a separate daughterboard to the left, presumably because of the limited space, with five wires running between the boards. What bothered me was how the 4.4mm socket was held down: hot glue, without another support structure. Inserting or withdrawing a plug puts force on the socket, and that mounting looked poorly equipped to keep it still.
How the Loose 4.4mm Socket Caused Dropouts
The 4.4mm balanced connection has a 5-pole layout: L+, L-, R+, R-, and Ground. Among the four conductors joining the daughterboard to the main PCB, L- also provides a physical anchor. Its connection is on the opposite side from the other four wires. Once the glue lost its hold, the socket could rock backward and forward, loading that anchor until it was close to disconnecting. The movement appeared to be the reason the signal became intermittent, rather than a problem with the earphones.
Repairing the Connection and Securing the Sockets
Having found the fault, I didn’t want merely to patch the same unstable joint and wait for it to fail again. I removed the loose existing wires and used silver solder to make a stronger direct connection on the PCB. The aim was to deal with the unreliable connection rather than leave it hanging from the same weakened support.
I also worked on the physical mounting so the sockets wouldn’t simply move and strain the repaired joint again. Between the adjoining faces of the 3.5mm and 4.4mm sockets, I added a drop of Loctite to hold them together mechanically. After that reinforcement, operating the connectors no longer made them wobble easily. Restoring the electrical connection and securing the parts were both part of this repair.
Final Thoughts
After reassembling the housing, I listened again. The channel that had been cutting in and out came through clearly again during that listening test, which was a relief. A familiar brand doesn’t prevent a disappointing internal design, and opening this one exposed a weakness I hadn’t expected from the outside. My Atom 4 is now held firmly together again. With this repair in place, it has also become a permanent part of my collection rather than something I would sell.
