Use these reverse-engineered registers (verified at 0x4C address):
The Cx31993 is a very popular audio codec (ADC/DAC) used in many Linux-based devices, notably Pine64 products like the PinePhone and PineBook Pro.
Use a TCXO (SiT1552) if you need low phase noise for 384kHz playback.
If you experience distortion, clipping, or "tinny" sound, the issue is likely or sample rate mismatches : cx31993 datasheet fix better
The CX31993 is not a bad chip; it is a great chip trapped behind bad documentation and lazy OEM integration. With these fixes, your $10 dongle will outperform most $50 "audiophile" portable DACs.
The "fix" for low volume or missing microphone input is usually not a driver issue, but a issue. The Cx31993 is highly configurable; if the mixer paths aren't set correctly, the mic bias voltage might be off, or the ADC gain might be zero.
Users frequently report a buzzing or "hissing" sound, especially with sensitive In-Ear Monitors (IEMs). Conexant (CX-Pro) CX31993 USB-C Amp/DAC Review With these fixes, your $10 dongle will outperform
The CX31993 (also known as ) is a high-performance, low-power USB-C DAC/Amp chip widely used in budget audiophile "dongles." It is highly regarded for its 32-bit / 384kHz support and impressive signal-to-noise ratio (SNR) of Concept Kart Key Specifications
The Conexant/Synaptics CX31993 is an integrated single-chip USB audio solution designed for low-power, high-fidelity portable applications. Key Specifications Up to 32-bit / 384kHz PCM playback.
However, if you have ever searched for a solution, you have likely hit a brick wall. Official datasheets are locked behind Conexant’s NDAs (Non-Disclosure Agreements), leaving firmware corrupted dongles, driver conflicts on Windows, and Android compatibility nightmares unresolved. Users frequently report a buzzing or "hissing" sound,
Finding a formal datasheet for the Synaptics Conexant CX31993
If the device stops working mid-song or isn't recognized by your phone: AUDIOCULAR Conexant CX Pro CX31993 USB-C DAC & Amp
Reverse on shutdown: HP amp off → RESET → DVDD off → AVDD off.