You use 8-16 Ohm IEMs at high volume for hours. In that case, buy a dongle with a discrete op-amp (e.g., the JCALLY JM20 or the Apple USB-C dongle, which runs ice cold). Conclusion: The Datasheet Doesn't Lie, But It Omitted Comfort The Conexant CX31993 is a marvel of budget audio engineering. The datasheet is technically correct that the chip is "low power"—from a silicon perspective. But the physical packaging, cheap LDOs, and lack of thermal management in $5 dongles make the user experience "hot."
The answer lies in the . The CX31993 contains an integrated headphone amplifier . The datasheet specifies that the chip can drive loads down to 16 Ohms. When you plug in high-sensitivity IEMs (like the Moondrop Chu or 7Hz Zero), the amp section works fine. cx31993 datasheet fix hot
If you own an CX31993-based adapter (commonly sold by brands like Avani, Abigail, or JCALLY), you may have touched the body after 20 minutes of use and felt a concerning, near-painful heat. Is this normal? Will it damage your phone or laptop? You use 8-16 Ohm IEMs at high volume for hours
To answer this, we have to go where no YouTuber has gone before: the . Since the datasheet is a restricted, technical document often hidden behind NDA walls, we have reverse-engineered the public specs, power delivery schematics, and user telemetry to diagnose why the chip runs hot and—most importantly— how to fix it. Part 1: What the Datasheet Doesn't Tell You (But We Do) The official Conexant (now Synaptics) CX31993 datasheet lists the chip as a "high-performance, low-power audio codec." The keyword is low power . The sheet claims a typical current consumption of 20-30mA for the digital-to-analog conversion. The datasheet is technically correct that the chip
But when you plug in headphones (32 Ohm or lower), or use a passive analog volume control (like a USB knob), the amplifier enters a Class A/B bias region where efficiency plummets.
By applying the , performing the Thermal Pad Mod , or simply buying an impedance adapter, you can continue enjoying 384kHz playback without burning your fingertips.
However, a widespread issue has plagued users across Reddit, Head-Fi, and GitHub forums: