Dirt and pocket lint inside your phone or laptop's USB-C port can cause intermittent drops in power, leading to glitching or digital noise.
But "datasheet specs" don't always tell the whole story. Here is how to actually fix common issues and make this tiny chip sound even better. 1. The Real "Fix": Add the MAX97220 Amp
The CX31993 is infamous for stuttering on ARM SBCs (Single Board Computers). The typical error is snd_pcm_recover underrun occurred . : Create an ALSA configuration file ( /etc/asound.conf or ~/.asoundrc ) to increase the buffer size significantly. Adding pcm.!default type hw card DAC and ctl.!default type hw card DAC can also force the system to use the correct audio parameters. If the issue persists, disable the onboard audio entirely in the BIOS or raspi-config to free up DMA channels for the USB DAC.
| Register | Function | Useful values | |----------|----------|----------------| | 0x03 | HP amp gain | 0x00 = -6dB, 0x02 = 0dB, 0x03 = +6dB | | 0x06 | Mixer control | Bit 3 = HP enable | | 0x0A | LED/GPIO | 0x01 = LED on | | 0x10 | PLL config | Default 0x88 for 44.1/48kHz |
The following data represents the core technical capabilities of the CX31993 chipset found across various implementations: Specification Conexant CX31993 Resolution Up to 32-bit / 384kHz Dynamic Range Distortion (THD+N) Output Power ~65mW into 32Ω Output Voltage Practical "Fixes" & Improvements Android Volume Limit: cx31993 datasheet fix better
The official documentation provided by Intel and Cirrus Logic for these codecs was famously sparse. While the standard HDA registers were documented, the proprietary "Processing Capsules" (DSP functions within the chip) were hidden behind a "Black Box" interface.
// Example of the "Fix" found in Linux Kernel Source (patch_cirrus.c) // This sequence was not in the original datasheet 0x11, AC_VERB_SET_COEF_INDEX, 0x0020 , // Unlock the secret register 0x11, AC_VERB_SET_PROC_COEF, 0x0001 , // Enable the specific output path
Use bit-perfect media players like UAPP (USB Audio Player Pro) , Hiby Music , or Neutron Music Player .
, Neutron Music Player , or . These apps bypass the Android system's audio stack and allow you to access the hardware-level volume control of the DAC. Dirt and pocket lint inside your phone or
By analyzing the internal architecture of the chip, applying hardware schematic fixes, and deploying bit-perfect software tweaks, you can bypass generic implementation flaws and make your audio setup perform significantly better. Technical Specifications Index
The (also known as the Conexant CX Pro
| Parameter | Specification | Notes & Confidence | | :--- | :--- | :--- | | | 32-bit | Official Conexant page via WarmSeaIC | | Max PCM Sample Rate | 384 kHz | Official Conexant page; confirmed by independent audio tests | | DSD Support | DSD64/128 (DoP) | Found in most dongle specs (e.g., JCALLY, Celest) | | SNR (Signal-to-Noise Ratio) | >128 dB | Widely cited in product specs / WarmSeaIC summary | | DNR (Dynamic Range) | >120 dB | Cited in many product descriptions | | THD+N (Total Harmonic Distortion + Noise) | <0.0003% | Cited in many product descriptions | | Output Power (Standard) | 65mW @ 16Ω / 30mW @ 32Ω | Cited in many product descriptions | | Supported Headphone Impedance | 16Ω – 600Ω | Cited in many product descriptions | | Power Supply Voltage | ~5V | USB bus-powered | | Power Consumption | Very low | "Runs cool" / consumes only a few milliamps per official CX31993 page | | Amplifier Topology | Class G (at least in Framework Card implementation) | Direct from a developer contact with Conexant | This noise might be filterable | | Output Voltage (Vrms) | 1.0–1.1V (standard standalone) | For standard CX31993 dongles, confirmed by ASR Meizu mBlu discussion | | Output Voltage (MAX97220 combo) | Up to ~2V (high-gain) | This voltage doubling may cause hiss with ultra-sensitive IEMs |
If you plug a removable cable into the dongle before connecting the earphones to the cable, the chip detects infinite impedance. It locks into an incorrect power state, resulting in a thin, distorted, or quiet sound profile. 2. Power Rail Isolation Constraints : Create an ALSA configuration file ( /etc/asound
The CX31993 is a highly popular, budget-friendly USB-C digital-to-analog converter (DAC) chip found in dozens of portable headphone dongles. While it offers impressive 32-bit/384kHz audio resolution for its price, users frequently encounter hardware quirks, driver conflicts, and configuration bottlenecks.
Whether you are wrestling with Windows crackles, Android silence, or low output volume, the solution is not to throw money at a new DAC, but to systematically apply the right fix. The goal is to transform this cheap, ubiquitous dongle from a source of frustration into the high-performance audio tool it was always meant to be.
, to provide a "better" and more powerful driving force for demanding headphones. According to product listings on and specialty retailers like ConceptKart , its core capabilities include: Hi-Res Audio Support : Maximum sampling rate of 32-bit / 384kHz , allowing for high-definition, lossless playback. High Signal-to-Noise Ratio (SNR) : Delivers an impressive -128dB SNR
This is perhaps the single most-reported problem with CX31993 dongles, particularly when the dongle is connected to a PC with an AMD GPU or a gaming motherboard.
Maximum sampling rate of 384 kHz | Volume adjustments and an equalizer | Signal-to-Noise Ratio (SNR) of -128dB | Output of 2 Vrms. Concept Kart