SMSL A50 Pro 2.1 Channel Amplifier Review

SMSL A50 Pro review featured

In this article, I review the SMSL A50 Pro 2.1 power amplifier. A50 Pro boasts 70W of output power for each main channel and 100W for the subwoofer. It’s priced at $89.

Disclaimer: This sample was provided by HiFi Express for an honest review. All observations and opinions here are my own, based on my experience with the product.

SMSL A50 Pro 2.1 Channel Amplifier Review
Add your rating here!1 Votes
Clear, uncoloured sound signature
Bass and treble tone controls
Compact size
5 EQ presets and 10 high-pass and low-pass crossover points
Multiple connectivity options
Not as insightful or nuanced as some higher-end amps
Our Score

SMSL A50 Pro

What's in the A50 Pro box
In the Box
  • SMSL A50 Pro
  • Remote control
  • Power adapter
  • Bluetooth antenna
  • USB cable
  • HDMI cable
SMSL A50 Pro design


The SMSL A50 Pro has a simple black box design. It has the same frosted cover on the front panel display that we saw on the SMSL D6S DAC. There is a multi-function volume knob and button and an OLED display on the front panel.

On the rear I/O panel, we find (from left to right): a Bluetooth antenna mount, a USB-C input, an HDMI (ARC) input, an optical input, a 3.5mm aux line and 3 pairs of speaker binding posts.

The A50 Pro is a 2.1-channel amplifier primarily designed for home theatre applications. It features the standard left and right stereo speaker outputs, as well as an output for passive subwoofers. The output power is 70W x2@4Ω for the main channels and 100W for the subwoofer out.

A50 Pro rear I/O

Internally, there are 2 Infineon MA12070P amplifier integrated circuits (IC). The MA12070P processes the incoming PCM digital signal using digital calculations. It converts this digital signal into a Pulse Width Modulation (PWM) signal. The PWM signal, now resembling an analog signal, is used to drive the speakers.

Typically, to convert digital signals back into analog form for output to speakers, a Digital-to-Analog Converter (DAC) is needed. However, in this setup, since the MA12070P directly generates the PWM signal from the digital input, there’s no need for a separate DAC.

Where the A50 shines is in the wealth of audio options. It comes with 5 EQ presets, as well as bass and treble tone controls. Furthermore, there are 10 high-pass crossover points from approximately 200Hz to 600Hz and 10 low-pass crossover points from approximately 50Hz to 120Hz. The passive subwoofer out volume can be adjusted independently from S00-S99.

Lastly, the A50 also has Bluetooth 5.0 but unfortunately, there’s no aptX or LDAC support.


Setup: I tested the SMSL A50 Pro first with my TV via HDMI and my aging ELAC B6 speakers. I don’t have a subwoofer in my living room so it was a simple 2.0 system. Additionally, I tested the amp using my PC as the source and my NHT C3 speakers – again in a 2.0 setup.

I don’t know if the claimed 70W per channel is accurate but I can say with certainty that the A50 Pro was more than a match for both pairs of speakers I tested and loud enough to make my windows shake like they were auditioning for a dance show.

The sound is clear, accurate and packed with detail. On the default settings, the A50 Pro sounds uncoloured with abundant clarity. The soundscape is wide and the imaging is exact for such a budget amplifier.

Once you dive into tweaking the sound, the A50 Pro really starts to flex its feature muscles. With 5 EQ modes plus bass and treble tone controls, there’s a lot of customization available. I only wish I had a passive subwoofer to test the crossover points but then again, I probably would have spent far too much time messing about with that, in a sandbox, unable to resist the allure of tweaking every possible setting to achieve the perfect balance of rumble and clarity.

The A50 Pro sounds more assured and robust than I expected it to. It remained composed even when I pushed it and didn’t break a sweat. Admittedly, my little bookshelf speaker setups aren’t demanding enough to put any serious strain on this amp but I think they’re fairly much in line with what most users who buy this will be using.

Sure, it may not have the character of an A-Class amp or the poise of higher-end models but for the money, the SMSL A50 Pro puts on an impressive performance.

SMSL A50 Pro rear of chassis


In conclusion, the SMSL A50 Pro is a solid contender in the budget amplifier market, boasting a sleek design and a plethora of connectivity options. Its 2.1-channel configuration caters well to home theatre setups, offering ample power output for both main channels and subwoofers.

What sets the A50 Pro apart, however, is its extensive audio customization features. With multiple EQ presets, tone controls, and adjustable crossover points, it gives you the freedom to tailor the experience to your preferences. While it may not have the refinement of higher-end models, its versatility makes it a standout choice for budget-conscious audiophiles seeking a capable amplifier for their home entertainment systems.

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