Updated October 2026 · specs checked Oct 10, 2026.
Quick Answer
The SU-1 is a very small standalone DAC (SMSL calls it “ultra-tiny”): USB-C in, RCA out, with optical and coaxial inputs too. It uses an AKM AK4493S chip (not an ESS chip, as some older listings say) and an XMOS XU316 USB receiver. It needs a separate headphone amp.
The most compact way to feed a budget amp: AK4493S, XU316 USB, optical and coaxial inputs.
Two AK4493S chips plus a remote, display and volume control, for buyers who want more features.
The all-Schiit option at $149, built to stack with a Magni.
Who should NOT buy the SU-1: anyone without a separate amp (buy a DAC/amp combo instead, see our best DAC/amp combos under $200 ), and anyone who wants a remote or balanced output.
Specs
| SMSL SU-1 | |
|---|---|
| DAC | AKM AK4493S |
| USB receiver | XMOS XU316 |
| Inputs | USB-C (power and data), optical, coaxial |
| Formats (USB) | PCM to 32-bit/768 kHz, DSD512, MQA |
| Output | RCA, 2.0 V RMS |
Figures are SMSL’s published specs as listed by retailers and reviewers.
SMSL in Context
SMSL, based in Shenzhen, and Topping are the two Chinese brands that dominate budget DACs and amps. SMSL often offers similar hardware to Topping at slightly lower prices with fewer extras. The SU-1 is its entry standalone DAC.
Build and Connections
The SU-1 is tiny and plain. USB-C carries both power and audio, which simplifies cabling, and optical and coaxial inputs cover a TV or console. Output is a single pair of RCA jacks at 2.0 V RMS, the standard line level that any budget amp expects.
Sound and Measurements
SMSL’s published distortion and noise figures are far below audibility, and owners consistently describe the SU-1 as clean and neutral. Between this, the E30 II and the Modi 5, the differences you’ll notice are features and size. The amp and headphones decide the sound.
The Budget Stack
Rated at 2.5 W into 32Ω and 415 mW into 300Ω, with a −10 dB gain setting for IEMs. $119.
About 2.6 W into 32Ω and compact enough to sit beside the SU-1. About $129 direct.
For headphone-specific amp advice, see the HD 600 , HD 560S , DT 770 Pro and HE400SE pairing guides.
Verdict
The SU-1 is a sensible first DAC for a separates stack if you want small and simple. If you’d use a remote or volume control, spend a little more on the Topping E30 II . For more options, see our best DACs under $200 .
