The SMSL AL400 is a modern all-in-one amplifier built for listeners who want serious hi-fi performance without filling the rack with separate boxes. It brings together a high-power stereo amplifier, a high-resolution DAC, a full phono stage, Bluetooth streaming, and HDMI eARC in a single, compact chassis—essentially a complete home audio hub for both music and TV.
At the heart of the AL400 is Texas Instruments’ proven TPA3255 power amplifier, delivering enough muscle to drive demanding speakers with ease. Whether you’re connecting passive speakers, feeding sound from a TV via HDMI eARC, spinning vinyl, streaming from a computer, or plugging in a set-top box, the AL400 is designed to handle it all cleanly and efficiently.
Digital duties are handled by a Cirrus Logic CS43131 DAC, paired with an XMOS XU-316 USB interface for ultra-stable data transfer. High-resolution support is comprehensive: PCM up to 768 kHz, DSD256, and full MQA and MQA-CD decoding via USB, optical, and coaxial inputs. For wireless listening, SMSL has included Qualcomm’s QCC5125 Bluetooth chipset with LDAC and aptX HD, ensuring high-quality playback from compatible smartphones and tablets.
Vinyl, TV, and fine-tuning
Unlike many compact amplifiers, the AL400 doesn’t treat vinyl as an afterthought. The built-in phono preamp supports both MM and MC cartridges, allowing direct connection of serious turntables without external gear.
Sound shaping is equally flexible. A three-band parametric EQ lets users adjust frequency, gain, and Q-factor to tailor the sound to their room or personal taste. Subwoofer integration is also well thought out, with 0°/180° phase selection, adjustable sub level, and four selectable low-frequency crossover points.
For TV setups, HDMI eARC enables high-quality audio return with automatic volume synchronization, making the AL400 a seamless upgrade from a soundbar while retaining proper stereo fidelity. Everyday control is handled via the included remote, which also allows screen brightness adjustment and automatic display shutoff for distraction-free listening.
Compact size, serious output
Despite its modest footprint, the AL400 delivers real power:
165 watts per channel into 4 ohms
85 watts per channel into 8 ohms
Measured performance is equally impressive, with low distortion, high signal-to-noise ratio, and excellent channel separation—numbers that reflect SMSL’s focus on clean, modern engineering rather than gimmicks.
SMSL AL400 – Key Specifications
Inputs: RCA / Bluetooth / USB / Optical / Coaxial / Phono / HDMI eARC
Output power (RMS): 165 W ×2 (4 Ω), 85 W ×2 (8 Ω)
THD+N: 0.003%
SNR: 101 dB
Channel separation: 100 dB
USB PCM: 44.1–768 kHz, 16–32 bit
USB DSD: DSD64–DSD256
Optical/Coaxial PCM: 44.1–192 kHz, 16–24 bit
Optical/Coaxial DSD: DSD64 (DoP)
MQA decoding: USB / Optical / Coaxial
MQA-CD decoding: Optical / Coaxial
USB mode: Asynchronous
OS support: Windows 7–11, macOS, Linux
Power consumption: 40 W
Dimensions: 254 × 45 × 210 mm
Weight: 1.7 kg
The SMSL AL400 is a compact but highly capable integrated amplifier that bridges modern digital audio, vinyl playback, and TV sound in one elegant solution—ideal for anyone who wants powerful, flexible hi-fi without the clutter.
