Интегральные усилители — SMSL AS400

The AS400 is a compact all-in-one integrated amplifier designed by SMSL in China, bringing together a DAC, an MM phono stage, a headphone amplifier, Bluetooth and HDMI ARC in a CNC-machined aluminium alloy chassis. Its amplifier section uses an Infineon MA5332MS Class D chip, the converter is a Cirrus Logic CS43131, USB is handled by an XMOS XU-316 and the volume is set by an NJW1194A chip.

Key specs that matter

SMSL quotes 2 x 85 W into 8 ohm and 2 x 165 W into 4 ohm, with THD+N of 0.003%. The signal to noise ratio is 107 dB and channel separation is 98 dB. Line input sensitivity is 280 mV with an input impedance of 22 kohm. The case measures 210.4 x 46 x 254 mm and weighs 1.568 kg, and power consumption is 40 W at normal volume from a 100 to 240 V AC supply. The launch price was USD 279, and the black chassis carries a silver anodised aluminium front plate.

Engineering and use context

Seven sources can be connected - USB-C, an RCA line input, Toslink optical, coaxial, HDMI ARC, a moving magnet phono input and Bluetooth with aptX HD, LDAC, SBC and AAC. Via its USB port the converter takes PCM up to 32-bit and 768 kHz, DSD256 and MQA, and MQA-CD decoding is also included, while the optical and coaxial inputs reach PCM at 24-bit and 192 kHz and DSD64 over DoP. Besides the speaker terminals, the rear panel carries an RCA preamplifier output meant for an active subwoofer, so the unit can run as a 2.1 system. Headphones connect through a balanced 4.4 mm socket or a single-ended 6.35 mm jack. The built-in phono stage is designed for MM cartridges only, so a turntable fitted with such a cartridge needs no separate phono preamplifier. The front panel has an integrated display and a multifunction button, and a plastic infrared remote control comes in the box together with an HDMI cable for the ARC link, a Bluetooth antenna, a USB cable for computer use and an IEC power cord. Bass and treble tone controls are built in.

Pairing

Passive speakers of either common impedance can be connected directly, and a powered sub plugs into the dedicated line output. A television links via HDMI ARC, a computer via USB-C, while phones and tablets stream wirelessly. The two headphone sockets let the same box serve as a headphone amplifier at a desk, with no speakers connected.

Alternatives

The SMSL AL400 is a related integrated amplifier with DAC built on a TPA3255 chip, adding HDMI eARC, MC phono support and a parametric equaliser.