Audio converter InLine 33054E USB-C to 3.5 mm with built‑in DAC, 15 cm cable

InLine 33054E USB-C to 3.5 mm with built‑in DAC, 15 cm cable is an active audio adapter that converts digital USB-C audio output to analogue via an integrated Conexant CX21988 codec. The compact aluminium-bodied adapter includes a 15 cm shielded cable and a 3.5 mm female jack that supports both audio output and microphone input. It is designed as a plug-and-play solution for smartphones, tablets and laptops without a dedicated headphone socket and enables high-resolution playback and reliable headset communication.

Advantages

The built-in DAC provides up to 96 kHz / 24‑bit digital-to-analogue conversion, while the ADC supports 48 kHz / 16‑bit microphone input, reducing distortion and signal loss for clearer sound. With a measured signal-to-noise ratio of 100 dB and THD+N of -85 dB, the adapter delivers clean and detailed audio reproduction. The adapter supports both CTIA and OMTP headset wiring standards and automatically detects insertion/removal of headphones. Its aluminium housing and shielded flexible cable improve durability and stable signal transmission. No additional drivers are required for most devices, enabling immediate plug-and-play use.

Suitable for (tasks / use cases)

• Listening to music from USB-C smartphones, tablets and laptops that lack a headphone jack
• Using stereo headsets with microphone for voice calls or video conferencing
• Basic on-the-go audio monitoring and playback with consumer headphones (typically around 32 Ω)
• Connecting analogue speakers or portable audio equipment with a 3.5 mm input

When it may not be suitable

This adapter is not a professional studio interface and does not replace multi-channel audio interfaces or devices that require balanced XLR or TRS connections. Users requiring ultra-high-end audiophile amplification, headphone amplifiers with high output power, or multi-channel routing should consider dedicated audio equipment. Compatibility with very old or non-standard USB-C implementations or proprietary smartphone audio modes cannot be guaranteed.

Key specifications

• Codec chip: Conexant CX21988
• Digital-to-analogue conversion (DAC): up to 96 kHz / 24 bit
• Analogue-to-digital conversion (ADC) for microphone: 48 kHz / 16 bit
• Signal-to-noise ratio (SNR): 100 dB
• Total harmonic distortion plus noise (THD+N): -85 dB
• Crosstalk suppression: -50 dB
• Headphone compatibility: CTIA and OMTP wiring standards
• Typical matching headphone impedance: ~32 ohms
• Cable length: 15 cm, shielded and flexible
• Housing material: aluminium
• Connector: USB-C male to 3.5 mm female jack

How to use

Connect the USB-C plug to a compatible phone, tablet or laptop and insert your 3.5 mm headphones or headset into the adapter jack. The device should recognize the adapter automatically and switch audio output to the connected headphones without installing drivers on most systems. For headsets with a microphone, the ADC handles voice input; select the adapter as the audio input device in your communication application if needed. To disconnect, remove the headphones and unplug the USB-C connector.

What to consider before purchase

• Ensure your device supports USB-C audio output and standard USB-C accessory operation
• Check whether your headset uses CTIA or OMTP wiring if microphone functionality is required
• Consider headphone impedance and sensitivity; very low-impedance or high-power headphones may need a dedicated amplifier
• Not intended as a multi-channel or professional audio interface

Usage recommendations

For best results, use with consumer headphones around 32 ohms and keep the 15 cm cable free from sharp bends. When using the microphone, confirm the adapter is selected as the input in your app settings. Avoid connecting to devices with non-standard USB-C implementations; if no audio is detected, try a different host device or check for software restrictions on USB audio output.