Усилители мощности стерео — SMSL VMV A1 Pro

The VMV A1 Pro is a compact two-channel power amplifier from SMSL, the Chinese electronics maker whose VMV label covers its higher-grade designs. It builds its output stage around gallium nitride transistors supplied by Infineon of Germany, and it can be switched from stereo operation to a bridged mono mode. The asking price in North America is USD 495, and the box includes a remote control.

Key specs that matter

In stereo mode the amplifier delivers 85 W per channel into 8 ohm and 160 W per channel into 4 ohm. Bridged as a mono block it gives 250 W into 8 ohm and 400 W into 4 ohm. THD+N is listed at 0.003 percent, the signal to noise ratio at 109 dB and the dynamic range at 111 dB, with channel separation of 75 dB. Input sensitivity is 680 mV at 22 kohm through the stereo RCA pair and 2100 mV at 22 kohm through the XLR socket used in mono mode. The case measures 210 x 47.6 x 201.6 mm and weighs 1.56 kg, small enough to sit beside a computer monitor or under a DAC.

Engineering and use context

GaN FET devices switch far faster than conventional silicon parts in class D circuits - SMSL quotes switching frequencies of up to 1 MHz - and that speed cuts switching losses and heat. The result shows in the power figures - standby draw is below 0.5 W and typical consumption in use is about 40 W, supplied by an internal switched-mode power unit that accepts 100 to 240 V mains. Level is set by a Texas Instruments PGA2311 volume chip, so the amplifier can be driven directly from a fixed-output DAC or streamer without a separate preamplifier. The housing is a machined aluminium chassis with gold-plated connectors, and built-in circuits guard against overheating and overcurrent. The maker grants twelve months of warranty cover.

Pairing

The balanced XLR input is reserved for bridged mono use, so a stereo pair of bridged units needs a front end that has balanced XLR outputs, feeding one channel to each amplifier. In stereo mode any RCA source with a standard line output reaches full output comfortably. The power reserve into low impedances allows bookshelf or floorstanding loudspeakers of moderate sensitivity, and the small footprint suits desktop systems built around passive monitors.

Alternatives

The SMSL VMV A1 is the class A FET model in the same range, rated at 10 W per channel into 8 ohm and 15 W into 4 ohm.