• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Ruizu X02 Unboxing and Initial Notes


Forum Donor
May 13, 2019
If you wander around Aliexpress or Amazon looking at cheap dedicated music players you will notice a wealth of low cost options. I am currently doing a project that involves collecting a lot of old FLAC recordings from the public domain and I decided to grab a cheap player that can do FLAC. If it works out, I will send the device loaded with old music as a gift to a family member. If it does not work out, I am $25 down and I have a story to tell.

So let's get started! Our subject today is the Ruizu X02 (2nd Generation). The first generation of this device was a pure music player. The second generation throws in FM radio and a recording function with a $1 price difference. What caught my eye was this outline of the product: "80時間の長いバッテリー寿命,ウルトラスリムMP3プレーヤー,アップグレードされたバージョン。使いやすい,8GBメモリ。128GBTFカードまで,高音質:MP3、WMA、APE、WAV、FLACを含みます。" 80 hours life. 8GB included. Expandable to 128GB with MicroSD card. Support for MP3, WMA, APE, WAV, FLAC. Same specs listed in English over at Aliexpress. My purchase was from Amazon this time around rather than Alibaba. The reason was simple enough - I paid an extra $9 but could get the device in short order.

This player has some coverage via subjective reviews over at Head-Fi. They make it sound good. However, there is a proviso they did not cover and which came back to bite me. That proviso is related to FLAC. See the end of this post.

Exciting times! Well, interesting times anyway.

The box itself is pretty bland.

The back gets a little more interesting as it teases FLAC support and a positive note about after-sales service.

The service-orientated aspect continues with another note and an email address on the side. This type of positive service is pretty common among companies based in Shenzhen and nearby locales.

Taking the wrapper off reveals a nicer front than before. This is far less exciting than the rear of the package though, and it raises an interesting perception point. These things are still being labelled MP3 players in 2019. Weird.

We have the usual envelope style of box. Easy to open and close. No objections.

The device slides out and is immediately presented to your eye though covered in a hazy plastic protection sleeve.

It looks pretty good visually but the feel is very, very cheap plastic. Insubstantial and potentially brittle come are thoughts that come to mind. However, this thing weights 30g so dropping it is unlikely to cause any damage.

Nothing special on the rear except one note of worth. It has CCC certification. Nice. Unlikely to have weird electrical problems.

The accessories are underneath the device with a side+top cover to protect them.

It is pretty basic in here. A pair of what look like nasty earphones and a USB to MicroUSB cable for data transfer and charging. The manual lurks below.

The manual is surprisingly thick. Unlike some devices this comes with quite a few pages covering the device and it provides those instructions in several languages.

A quick glimpse of the internal index page of the languages covered in my copy delivered to the Japanese market.

Pulling open the manual and flicking through I had cause to pause when the data about supported files covered FLAC. What's this bitrate? 1,200Kbs? Wait...what does this mean for the files I want to use? The sample rate is also worth of note, firstly because they mistakenly wrote the values in MHz instead of the correct kHz, and secondly because we have a hard limit of 48kHz.

Argh! This is a pretty heavy limit. Just look at the test FLAC file you can get from the Sony website. A free tool called MediaInfo showed 24bit at 92kHz with a bitrate of...3,329Kbs. Sure enough, it did not work on the player and an "unsupported file" error was thrown.

This is where using a Mac really started to bite. There are plenty tools for messing around the FLAC on Windows machines and Linux machines. I have both to hand but I wanted to continue as if I had one computer. Google was heavily used, trial and error played a part, and several disappointments like VLC failing to convert files effectively from FLAC to FLAC kept me busy. Eventually a 21 day free trial of a tool called dBpoweramp Music Converter allowed me to drop the Sony file to 16bit at 48kHz. 24bit at 48kHz was still showing a bitrate above our maximum of 1,200Kbs.
Screen Shot 2019-05-28 at 22.28.39.png

This was confirmed by our free friend MediaInfo. Nice. Er. Well, 994kbs rather than the 1000-1200 range specified on the Ruizu X02 manual, but I am going to bet they were focusing on the maximum value rather than expressing a limited total range.the Sony file to 16bit at 48kHz.
Screen Shot 2019-05-28 at 22.29.36.png

The file worked as expected and off I went to finalize the unboxing. The player has a really intuitive home screen. I like the way music is front, center and highlighted to begin. You just click and off you go.

I plugged the device into the computer to transfer over some music. It opens as a normal USB device.

On the computer you see some logical folders laying out where content lives and content can be placed.

There is a simple and pleasant surprise in the music folder. It has been pre-loaded with a couple of MP3 tracks to get you started. It is a nice touch that someone can turn the device on and listen to a song right away. You will notice ".lrc" files adjacent to the two included tracks that display lyrics on the screen as the music plays. Sweet. You may also notice that I was super lazy and did not rename my test FLAC file to reflect it was no longer 24bit 92kHz but rather 16bit 48kHz. This is a horror we shall just have to live with.

At this point I unplugged the device and started messing with it as a player. Sound settings appeared to be a natural place to start.

Honestly this was a little more basic than I expected.

Still, what it provides is much in line with what you see on Apple devices, and should be fine for messing around with the EQ in a casual manner.

The last item of note from my initial look was the language settings.

With 25 languages pre-loaded this truly is an international device and - if you are someone thinking about providing a cheap, cheerful but functional music player to a relative abroad, this option should have you covered.

Actually playing music on the player worked. I pulled out the trusty Bose QC35 (powered off) and the music came through with no issues from a 16bit 48kHz FLAC file. I defer to my betters to identify the specific DAC chip used in this device but I can say that it just works in a manner that will be satisfying to the vast majority of potential users. The key sticking point for music fidelity will probably be the headphones used.

Wait, you say. This unboxing hit a snag around FLAC. Is it a killer snag?

It depends on your use-case. It is certainly disappointing for me.

To recap, the Ruizu has a limit of a 1,200Kbs bitrate and 48kHz sample rate for FLAC. This is a pretty heavy limit that only became evident when I unboxed and read the manual. The test FLAC file I tend to use from the Sony website is 24bit at 92kHz with a bitrate of 3,329Kbs. Sure enough, it got an "unsupported file" error. The eventual solution was to downsample. More specifically, I had to drop the Sony file to 16bit at 48kHz to obtain a bitrate of 994Kbs because even 24bit at 48kHz was showing a bitrate between 1,700 and 1,900Kbs depending on the FLAC file efficiency used (more on that below).

Downsampling on a Mac involved one freeware program to monitor bitrates and one trial software to convert FLAC from 24bit at 92kHz to 16bit at 48kHz. It took some testing as detailed earlier in this article to get there. This is not something I am particularly looking forward to when preparing the device for my family member. Sighs. Googling suggest this process would be a lot easier and quicker on a Windows or Linux machine. I leave the floor open to others for suggesting more elegant ways to accomplish this on a Mac.

My take at this juncture is that the snag around FLAC is an annoyance that tips the device into the "almost not worth it even at this price" box for any FLAC users. On the other hand, if you are planning to give someone a device to play MP3s or WAV files which max out at 320Kbs 48kHz and 384Kbs and 48kHz respectively, then this is a great little tool. It is cheap enough to give to kids and capable enough to make an adult happy.

FLAC File Efficiency

L0 to L8 or LossLess Levels 0 to 8 are the values used by most tools to express whether they are preparing the file as lossless fast (L0) or with more processing to make the file a few percentage points smaller (L8 being the most processed). This is not something you need to worry about except in really edge audio cases. For what it is worth, the Ruizu X02 manual makes reference to supporting the full range of L0 to L8 so you should never hit any issues as long as your bitrate is below 1,200Kbs and your sample rate is no more than 48kHz.


  • IMG_4799.jpg
    1.3 MB · Views: 170
  • IMG_4812.jpg
    1.6 MB · Views: 350
Last edited:


Forum Donor
May 13, 2019
Nice write-up!
That is a strange limitation Flac data rate in this day and age....

Hey, thank you! Means a lot coming from you.
I am tremendously curious about the DAC chip used. How about I sacrifice the device, take PCB shots, and see if we can identify? Happy to do so if we have the knowledge resources to make it worthwhile ;)

(link for readers unfamiliar with the term PCB)


Dec 20, 2021
That's the review I am looking for the right one. How can I buy this one in India?
Top Bottom