Audirect ATOM4 Portable DAC Amp with ESS9281AC PRO Chip

The Audirect ATOM4 is a pocket-sized portable DAC amp that upgrades the sound from your smartphone, tablet or computer. It pairs an ESS9281AC PRO DAC chip with dual RT6863C amplifiers to deliver detailed, clean audio from the USB-C port you already have.

If you are looking for an Audirect DAC that fits in your pocket, the ATOM4 offers both a 4.4mm balanced output and a 3.5mm single-ended output. That means you can use it with most wired headphones and IEMs, whether you listen on the commute, at your desk or at home.

It weighs about 19g, has no battery to charge, and works as a plug-and-play USB audio device with compatible hardware.

Key Features of the Audirect ATOM4 Portable DAC Amp

• ESS9281AC PRO DAC chip: Converts digital audio with high accuracy, so you hear more detail in high-resolution music files.
• Dual RT6863C amplifiers: Two operational amplifiers in the headphone amplification stage help drive your headphones or IEMs with a clean signal.
• PCM 32-bit/768kHz decoding: Supports high-resolution PCM files, so your lossless and hi-res libraries play at their full quality.
• DSD512 support: Plays native DSD content up to DSD512 for listeners who collect high-end audio formats.
• 4.4mm balanced output (up to 4.2Vrms): Offers a higher output level for balanced headphones and IEMs that need more drive.
• 3.5mm single-ended output (up to 2Vrms): Works with the standard headphone plug found on most everyday earphones and headphones.
• Independent circuit design: Separate digital and analog power sections are designed to reduce interference, helping keep the sound clean.
• Low distortion (0.0004% THD+N, manufacturer-reported): Helps keep the music accurate and free of audible coloration.
• USB-C connectivity: Connects to compatible smartphones, tablets and computers, so setup is quick and simple.
• Compact metal body (about 19g): Durable and light enough to carry in a pocket or bag all day.
• Plug-and-play and bus-powered: Draws power from the connected device, so there is no battery to charge or replace.

Why Choose the Audirect ATOM4 Portable DAC Amp?

Phones and laptops are built for convenience, and their built-in audio is rarely tuned for critical listening. The ATOM4 gives you a dedicated DAC and headphone amplifier without carrying a bulky device.

With the ESS9281AC PRO chip, a signal-to-noise ratio of about 119dB and frequency response within ±0.08dB up to 40kHz, it is built for clean, detailed playback. This Audirect DAC suits listeners who want a clear step up from a phone or laptop headphone jack.

The 4.4mm balanced output delivers up to 137mW at 32Ω and 29mW at 600Ω, so it can drive a wide range of headphones and IEMs. The 3.5mm output keeps it compatible with the gear you already own.

Because it is bus-powered with no built-in battery, the ATOM4 is always ready when you plug it in.

Technical Specifications