Nobsound TPA3255 HiFi 300W + 300W Bluetooth 5.0 Digital Power Amplifier Class D Stereo Audio Amplifier ● Supports input from iPods, smartphones, MP3 players, TVs, MP3s, CD players, laptops, desktop computers, or other devices via stereo RCA and wireless Bluetooth input. Adopts the QCC3003 Bluetooth chip, which has strong compatibility with many Bluetooth devices, to achieve lossless transmission. ● Can reach 300W + 300W, easily driving large passive speakers. ● With tone control, you can individually adjust the treble, mid, and bass to provide a very delicate sound suitable for various listening styles. A bypass switch (treble knob) is specially designed to turn the tone control on/off and enjoy the original sound. Uses high-quality components to ensure HiFi sound and long-term stable operation. Built-in high-power, high-efficiency switching power supply, can be used globally with an operating voltage of AC 100-240V. High-precision chip resistors are used to improve the signal-to-noise ratio. Special inductance for audio is used to ensure clear and powerful sound. The above is the official product description. As mentioned in Amazon reviews, "When you turn the high tone control, there's a popping sound, and the sound suddenly becomes muddy." This is the situation. It seems to be a specification, but due to this situation, please refrain from purchasing if you are concerned. There are no other concerns, and it works without problems. Ships via Rakuraku Mercari Bin or Takkyubin (Yamato Transport).