Audirect Atom 4 USB-C DAC & Headphone Amplifier Dongle
Audirect Atom 4 USB-C DAC & Headphone Amplifier Dongle
Audirect Atom 4 — Portable USB-C DAC & Headphone Amplifier Dongle
Unlock studio-grade audio from your smartphone, tablet, or laptop with the Audirect Atom 4. Powered by the flagship ESS9281AC PRO DAC chip and a two-stage amplification circuit, the Atom 4 delivers audiophile-level clarity, dynamics, and power in a pocket-sized dongle weighing just 19 g. Whether you prefer single-ended or fully balanced listening, the Atom 4 has you covered with both a 3.5 mm SE output and a 4.4 mm balanced output — all driven by True Balanced architecture for ultra-low noise and distortion.
Key Features
- ESS9281AC PRO DAC Chip — High-resolution decoding up to 32-bit / 768 kHz PCM and DSD512
- True Balanced 4.4 mm Output — Dual RT6863C op-amps in the first stage; switching amplifier in the second stage for exceptional headroom
- High Output Power — Up to 4.2 Vrms (balanced); ≥ 126 mW @ 32 Ω; ≥ 7 mW @ 600 Ω — drives everything from sensitive IEMs to demanding full-size headphones
- Ultra-Low Distortion — THD+N: 0.0004%; SNR: −119 dB for pristine, artifact-free sound
- Flat Frequency Response — < ±0.08 dB up to 40 kHz ensures true-to-recording accuracy
- Universal Compatibility — USB Type-C input works with Android smartphones, Windows, macOS, and more (USB Type-A adapter-friendly)
- Ultra-Compact & Bus-Powered — 19 g, no built-in battery required; draws power directly from your host device
- Plastic Housing — Lightweight and durable for everyday on-the-go use
Technical Specifications
| Model | Atom 4 |
| DAC Chip | ESS9281AC PRO × 1 |
| Op-Amp | RT6863C × 2 |
| Audio Input | USB Type-C |
| Audio Output | 3.5 mm Single-Ended / 4.4 mm Balanced |
| Frequency Response | < ±0.08 dB up to 40 kHz |
| Max Output Voltage | Up to 4.2 Vrms (Balanced) |
| Output Power (32 Ω) | ≥ 126 mW (Current Drive) / ≥ 137 mW (Current Drive) |
| Output Power (600 Ω) | ≥ 7 mW (Voltage Drive) / ≥ 29 mW (Voltage Drive) |
| SNR | −119 dB |
| THD+N | 0.0004% |
| PCM Sampling Rate | Up to 32-bit / 768 kHz |
| DSD Support | Up to DSD512 (2.8224 MHz DSD64 base) |
| Weight | 19 g |
| Built-in Battery | No (bus-powered) |
| Housing Material | Plastic |
| Country of Origin | Made in Mainland China |
Who Is the Atom 4 For?
The Audirect Atom 4 is ideal for audiophiles, musicians, and everyday music lovers who want a significant upgrade over their device's built-in audio output without carrying bulky equipment. Its True Balanced 4.4 mm output pairs beautifully with high-end IEMs and full-size headphones alike, making it a versatile companion for commuting, travel, home listening, and studio monitoring on the go.
For more information on high-resolution audio standards and formats, visit the National Institute of Standards and Technology (NIST) for technical audio measurement references.
Frequently Asked Questions
Q: What devices are compatible with the Audirect Atom 4 USB-C DAC dongle?
A: The Atom 4 is compatible with any device featuring a USB Type-C port that supports USB audio output, including Android smartphones, Windows PCs, macOS laptops, and iPads with USB-C. For USB Type-A computers, a standard USB-C to USB-A adapter (not included) can be used.
Q: What is the difference between the 3.5 mm and 4.4 mm outputs on the Atom 4?
A: The 3.5 mm output is a standard single-ended connection suited for most consumer headphones and IEMs. The 4.4 mm output is a True Balanced connection that provides higher output voltage (up to 4.2 Vrms), lower crosstalk, and greater dynamic range — ideal for balanced-terminated audiophile headphones and in-ear monitors.
Q: Does the Audirect Atom 4 support hi-res audio formats like DSD and MQA?
A: Yes, the Atom 4 supports PCM up to 32-bit / 768 kHz and DSD up to DSD512 via its ESS9281AC PRO chip. MQA support depends on your playback software's unfolding capability — the Atom 4 will pass through the decoded stream at full resolution.
Q: Does the Atom 4 require a battery or external power source?
A: No. The Atom 4 is entirely bus-powered, drawing its operating power directly from the connected host device's USB port. There is no built-in battery, keeping the dongle lightweight at just 19 g.