SMSL AD18 Bluetooth Amplifier 80W Power Amplifier Review

I was looking for an Bluetooth amplifier to hook up a pair of small speakers that I had in my room. I mostly use the speaker for streaming audio and as there is not a lot of space in the room; a small amp can be the right choice.

 After browsing through quite a lot of Bluetooth amplifier, I finally settled for AD18 4.2 HiFi USB DSP Digital Decoding Power Amplifier. 

It features an inbuilt DAC, has Bluetooth, and its compact build made it the best choice. But was AD18 able to deliver the performance I was expecting? Let us try to find out in this review!

First Impression

The first thing that I noticed about this Bluetooth amplifier is its compact build. It is pretty small when compared to my Onkyo or NAD. Its size is around half the size of a brick. Moreover, it is very light in weight too. If you are searching for an amplifier that is portable or one that can be easily hidden in your room, this AD18 is surely a great option. However, the power brick which comes with this amp is just as big as the amp.

AD18 also comes with a Bluetooth antenna which you need to connect to the slot at the back of the amp. You are all set to stream your favorite audio once the Bluetooth antenna is fixed and the amp is up and running.

Menu and Setup

While the display of this Bluetooth stereo receiver is not very large, it is easy to read. Below the display is a large dial which is multipurpose. It is used for adjusting audio, menu selection, and is also the main power button. The Chinese engineers have definitely done a marvelous job with the design and simplicity of the amp. Even the chassis is pretty strong and nothing close to the cheap Chinese amps that you find in the market.

The amp comes with a small remote control which is around half the size of my credit card and is pretty handy. Make sure that you turn the batteries before using the remote as they are fixed in the opposite direction to avoid power draining. All the functions can be easily managed with the help of the remote control. You can use the round dial to adjust the volume and the maximum you can reach is 60.

The first selection in the menu is for selecting an input source. There are a total of 5 input options- Coax, Micro USB, Optical, Aux, and Bluetooth. The Bluetooth version is 4.2 and is compatible with aptX. Also, make a note that the coax of this Bluetooth amplifier is not RCA but jack type. The next option helps you select the output between speakers and headphones. The headphone amp output is highly impressive. Next on the menu is the EQ. There are 6 settings which include rock, jazz, etc. 

This is followed by the option to adjust treble and bass. There are 3 different +/- levels for this setting. The next menu option helps you change the color of the display. There are three color options- green, blue, and white and the visibility is good in every color. The menu that comes with AD18 is most basic but is very useful if you are using an amplifier with Bluetooth for the first time.

bluetooth stereo receiver
bluetooth stereo receiver

Sound Quality

I tested the amp with iPhone streaming, MX cables, Marantz CD 6006 through optical, Tannoy speakers, and even used the USB input for Rpi music server. The quality was compared with similar sources and with the same speakers.

Let us first talk about Bluetooth streaming. When I connected to its Bluetooth for iPhone streaming, the sound was very clear and free from any kind of distortion. The reception and range of its Bluetooth is impressive. First I used my headphones to listen and its headphone amp is pretty great too. Then when I switched to speakers, the sound was again very much engaging.

However, after a few minutes, I felt that something was missing. Wait for a second, where is the bass? I tried to switch sources and tracks but the default bass was pretty much missing in my room that is generally boomy otherwise. Then I changed the bass from 0 to 1 and that was it, the bass was easily evident now. And when I increased it to 3, the bass was almost equal to the Nad amp that I have.

Switching of sources is easy too and the built-in DAC is of excellent quality. When I tried the analog feed from the Gungnir DAC to this Bluetooth stereo receiver, it was not very impressive. I liked it much better when the digital input was directly given to AD18. So, if you generally rely on analog sources, AD18 might not be the best choice for you.

Overall, the sound quality is precise and engaging. For casual listening, you won’t be required to go above the 35 volume level. Everything is pretty smooth without any humming or distorting sounds. The audio quality starts to suffer if you increase the volume above 50. I found it highly enjoyable for many different genres of music.

Pros and Cons

While everything about this Bluetooth amplifier is pretty impressive, especially at this price point, it does have a few flaws too. Let us have a look at some of the pros and cons of this amp.


Power output is decent

  Onboard DAC is good

  Bluetooth connection is very good

  Headphone is great too

  Excellent build quality


  Lightweight and compact build

  Wide range of digital inputs to choose from

  Sound quality is great for casual listening


The sound quality is not very good with analog input

Default bass should have been better

The output is distorted at higher volume levels,


AD18 is very easy to use, offers multiple input options, comes with a handy remote control and delivers excellent audio output with different sources. If you are searching for a compact and durable amplifier with Bluetooth which is not highly expensive and delivers decent performance for casual listening, SMSL AD18 is surely a great option.