Xiaomi launched a product called HiFi Decoding Headphone Amplifier [Quick Charge Version], model MDY-12-EP, which is what we can call a linear sound card. Its design is quite special. In addition to being used as a sound card, it also has a USB Type-C charging port, which can be used for fast PD charging while listening to songs. Also because of the addition of this function, the shape of the sound card is unique.
Xiaomi’s official website emphasized that this product uses Cirrus Logic’s CS43131 DAC chip. Compared with the previous CS43130, its performance indicators have improved, but this is not the most important thing. We found this on many CS43131-based products. The sound aesthetic of this chip is different from that of CS43130, it has returned to the traditional warm and soft style of Cirrus Logic.
The controller is not mentioned in the copy of Xiaomi’s official website. However, in the rendering of the product perspective structure, the chip model is indicated, namely Cirrus Logic CS46L41. This chip integrates the USB audio I/O controller and CODEC, and the headphone amplifier part, but for this product design, the DAC and headphone amplifier part of the CODEC should be idle. We don’t know much about the more detailed performance parameters of CS46L41. There are not many products using this chip, and the slightly well-known product in the impression is also a certain family of linear sound card products.
Xiaomi calls this product “large thrust up to 600Ω”. This description is problematic. Ohm is the impedance unit. Xiaomi’s original intention is to express that this product has a strong driving force. The CS43131 built-in headphone amplifier can support 30 milliwatts per channel under a 32-ohm load, and 5 milliwatts per channel under a 600-ohm load. It is difficult to push a 600-ohm headset with such power, but it is sufficient for the current sale of most of the small and medium-sized earphones.
Its sound style is neutral and warm, the sound is balanced, the sound has a certain density, is not loose, and the resolution is not excellent, but it is not bad. The dynamic transient performance is the same, and it is more than the best. There are no characteristics, but there are no major problems. Compared with the built-in audio system of most conventionally designed mobile phones, the sound is significantly improved, so plug a cable to change the world. It is definitely stronger than the HTC line of the year. 
This product has also been added with a charging function to realize the application requirements of charging while listening to songs. To meet the needs of fast charging, the wire material is very solid, but the thick and hard wire is relatively negative for the user experience. Putting it in your pocket or bag will be quite responsive.