The materials used in D231 are very sincere. The socket is gold-plated, which is more . The large heat sink ensures long-term stable operation, and the large-capacity filter capacitor makes the power supply more stable and the ripple is lower. The op amp uses NE5532, which is pluggable and can be upgraded to a more advanced op amp. QCC3084 is a new Bluetooth 5.4 chip that supports LDAC, LHDC, APTXLL. The Bluetooth decoding uses PCM5102, which makes the Bluetooth sound quality comparable to wired transmission. The design has a delayed power-on function to prevent when the power plug is inserted. D231 can not only adjust the high and low frequencies of the left and right channels to adapt to different speakers, but also independently adjust the volume and low-pass frequency of the subwoofer output, so that it can be well connected with the speakers of the left and right channels, making the entire sound field positioning more natural, and the low frequency be cleaner and more flexible. [Safety Protection]The amplifier board has short circuit, overcurrent, overheating and anti-static protection to prevent complete failure. When overloaded, the device reports a fault condition to the processor to protect itself from damage Color:As Shown Material:PCB Package Contents: 1 * Amplifier board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.