I purchased the above product from a well-known store, after researching reviews on mainly English-speaking sites. I wanted something that I could use for both my mobile phone and as a relatively good quality PDA (mp3 - flac etc player), although its performance without this accessory was not bad.
1. In terms of sound quality, it is quite good but not in the top category. I would describe its sound as relatively detailed, but not as dynamic as the desktop DAC-amp that I use. For the genres of music I listen to, it is more than sufficient. The chips it has inside (for DAC & AMP) are better than those in the Shanling M2x mp3 player of the same company, but I would say that the sound is not much better. However, I will wait for it to play for a while for a safe comparison.
2. The pairing for Bluetooth is fast. Essentially, it is a Bluetooth receiver, so it probably cannot be used with Bluetooth headphones, but with regular wired ones, either in balanced or single-ended output. The power is satisfactory for IEMs, from the simple output. It is not suitable for difficult-to-drive headphones, or it reaches its limits with them. It has several settings, but not all of them are available using the special Shanling mobile application, because the DAC chip is of a newer generation and the programs for its full utilization have not been written yet, mainly in the equalization area. It is better to play it from a player app that has its own equalizer, Shanling recommends the eddict player, or to install a general Android equalizer on your mobile phone.
3. Basically, I did not want to use it via Bluetooth but through a USB cable, but it did not connect that way with its existing cable until I found out that on the Realme 6 Pro, you need to enable the feature in Android 11, and possibly re-enable it every time, but eventually it works. The same may apply to other mobile phone brands, to the extent that they have Android 11. I am writing this in case someone encounters the same problem.
4. It is advisable to upgrade the firmware from 1.60 to 1.63, which is the current version, before using it. The price is a bit high compared to the previous one, although it is better. It also functions as a desktop DAC-amp if you download the Shanling drivers for Windows, as well as for Linux. I have not compared the sound quality via Bluetooth and USB, I will wait for it to burn in for about 50 to 100 hours before deciding.
5. Since I am not particularly interested in Bluetooth at the moment, maybe this specific purchase was overkill, and I should have looked at the corresponding USB products from the same company, such as the UA1 or UA2. They might have been more user-friendly for what I want. But again, this one is much more versatile for any use. It is positive that it has its own battery, small but sufficient for 5-6 hours, so it does not need to draw power from the mobile phone. It also has a screen for settings, small but convenient. Overall, I would give it somewhere between 3 and 4 stars, mainly due to the price, let's say 3.5 stars for now, unless it surprises me with its sound quality in the future, since the specifications are on par with the Shanling M3x player.