SMSL PA40 Review – Digital Power AMP
The SMSL PA40 is a high-efficiency digital power amplifier featuring the Infineon MA5332 Class D amplifier chip, designed to deliver low distortion, low noise, and a wide dynamic range. Equipped with audiophile-grade components and a built-in power supply, it offers both impressive performance and convenience. The PA40 includes an NJU7391A electronic volume control chip for surround sound and tone control, providing a refined listening experience. Ideal for home audio setups, this compact amplifier combines power, quality, and user-friendly features like EQ and bass/treble adjustments, as well as remote control functionality.
The PA40 amplifier is designed with premium components to ensure excellent sound quality and reliable operation, featuring overcurrent, overheating, and under-voltage protection circuits for a seamless and safe listening experience. At its core is the NJU7391A electronic volume control chip from Nisshinbo Micro Devices, a 2-channel chip that provides low noise, and low distortion, and supports surround sound and tone control to enhance audio performance.
Complementing this is the MA5332 Class D amplifier chip from Infineon, which offers standard protection and reliable performance in various environments. With its high energy conversion efficiency, the PA40 minimizes heat generation and energy consumption.
The PA40 amplifier delivers exceptional audio performance with its low distortion, low noise, and wide dynamic range. It surpasses traditional amplifiers in sound quality, offering clearer audio, reduced noise, and enhanced low-frequency response.
The PA40 amplifier is equipped with high-quality gold-plated input and output terminals, designed to offer superior durability and conductivity. These terminals not only ensure a longer service life by resisting corrosion but also reduce the need for frequent maintenance, providing a stable and reliable connection for optimal audio performance.
The PA40 features a built-in power supply, eliminating the need for additional adapters and reducing cable clutter to keep your workspace neat. This design not only minimizes potential electromagnetic interference from external adapters but also ensures a stable power source, optimizing the amplifier’s overall performance. Additionally, the built-in power supply makes the unit easier to carry, install, and move, offering convenience and portability.
The PA40 comes with an easy-to-use remote control, allowing you to conveniently power on/off, switch functions, adjust volume, and turn off the screen from a distance. For detailed operation instructions, please refer to the user manual.
While powered on, each short press of the knob cycles through adjustments for “Volume,” “EQ,” “Bass,” “Treble,” “Gain,” and “Brightness,” allowing you to fine-tune your audio settings with ease.
Features
- High-Efficiency Class D Amplification: Powered by the Infineon MA5332 chip, the PA40 offers high conversion efficiency with minimal heat and energy consumption, perfect for continuous use.
- Built-in Power Supply: Eliminates the need for external adapters, reducing cable clutter and electromagnetic interference for a stable, optimized performance.
- Audiophile-Level Sound Quality: Low distortion (THD+N 0.004%) and high SNR (100dB) ensure clear, high-quality audio with excellent low-frequency response and minimal noise.
- NJU7391A Volume Control Chip: Features surround sound capabilities and precise tone control, enhancing the richness and detail of your audio.
- Comprehensive EQ, Bass, and Treble Adjustments: Easily adjust volume, EQ, bass, treble, gain, and screen brightness using the front knob, allowing fine-tuned sound customization.
- Gold-Plated Terminals: High-quality gold-plated RCA inputs and speaker outputs ensure durability and reliable connectivity, extending the lifespan of the amplifier.
- Remote Control Included: Conveniently control power, volume, and other settings from a distance, ideal for hassle-free operation.
Technical Details
- Input: RCA
- THD+N: 0.00004
- SNR: 100dB
- Channel Separation: 72dB
- Input Sensitivity/Input Impedance: High Gain: 315mV / 20kΩ; Low Gain: 580mV / 20kΩ
- Output Power: 165W x 2 (4Ω); 85W x 2 (8Ω)
- Power Consumption: 40W (Normal Volume)
- Size (WxHxD): 191.6 x 41.6 x 185 mm
- Weight: 1.26kg / 2.77lbs
- Inside the Box: 1 x SMSL PA40, User Manual
- Price: $139
Unboxing
Sound
Once the music started playing, SMSL PA40 proved itself to be more than capable. Its sound signature is very neutral. The bassline is present, well-controlled, and revealing. The bass coming from stringed instruments vibrates and offers that stringy texture as it should. This is not given and most budget amplifiers will simply gloss this texture over and drown it in the sea of warm and rounded bass that’s as slow to stop as it is to start. Not the SMSL PA40 whose bassline is firm and nimble.
The midrange is once again dead neutral and informative. Plenty of details are revealed in this critical region, nothing is sweetened and warmed, but even more importantly there are no digital nasties to be heard. This means that the SMSL PA40 doesn’t sound oversharpened, edgy, or unnatural in any way. No, there’s even a dose of softness in the midrange that shows just how mature class D has become over the last few years.
I won’t talk about the highs for too long because they share the character with the midrange – well-extended and informative, but not tacky in any way. Frequency response from top to bottom is well blended and there are no parts that will protrude over the sound as a whole.
When it comes to dynamics, the SMSL PA40 is not capable of pulling big dynamic swings depending on your source, but I have yet to encounter an integration near this price that can. On the other hand, a small SMSL is much more skilled when it comes to microdynamics. It presents us with a quick and nimble sound that has no trouble following the speediest of rhythms. Because of this, the PA40 sounds lively and resolving at all times.
Finally, if we focus our attention on the soundstage, the SMSL PA40 is a pretty decent performer. All tones are clean and well separated so you can follow even more complex songs with ease. Sure, you can always confuse it with a full-sized classical orchestra, but that kind of music is the most difficult to tackle and no amp in this class would fare any better. Aside from that, SMSL PA40 proved to be a true allrounder who’s not too picky about music genres. The soundstage itself is decently spacious and airy.
Sum-Up
I reviewed the SMSL AO300 Dijital AMP about a year ago that also had a DAC inside, it sounded good for the asking price. The SMSL PA40 on the other hand is a AMP-only unit for your passive speakers and needs to be connected to a power source. My source was the SMSL DO300EX in this review and oh my, the difference is night and day regarding the sound coming out from the same 20-year-old desktop speakers of mine.
The PA40 may seem poor for input options because it only has one (RCA), but if you have the right setup as I do, the performance and joy is was more bigger for what you pay. This unit stays on my desk.