Integrated Hifi audio amplifier S.M.S.L A12 is a class d amplifier for passive speaker. It is compact powerful and competitive. Advanced circuit design makes the sound impeccable. The main Bluetooth input and RCA input can meet most of your needs, and it also comes with usb Input and U disk playback. Classic manual control, more stable, Patented SDB sound and+-12 level treble and bass adjustment, allowing you to enjoy high-quality music. (When switching to USB input, you may need to re-plug the USB cable or restart. That is determined by the chip, since the chip has priority functions. Please read the manual carefully before use). Our Story S.M.S.L was founded in 2009 which located in Shenzhen. Our company is specialized in the power amplifier, audio DAC, stereo headphone amplifier, and with own R＆D, manufacturing and marketing team. More than10 senior engineers with rich experience in product development and professional management are working hard to ensure each product is qualified and works excellent. We follow the rules of "quality-based, technology-guidance, customer central". S.M.S.L A12 Amplifier Small Bluetooth 5.0 Stereo Audio Amplifier 2 Channel for Passive Speaker New technology class d amplifier chip Infineon's MA12070 adopts a new power amplifier architecture MERUS, which is completely difference from the traditional class D power amplifier. In this desigh, each half-bridge uses four mosfets(M1-M4), and the capacitor "flying" between them as an additional power supply. Rail to generate a three-level output signal at the output switch node. Package Included: Audio Amplifier-1 24V Power Supply-1 Anti-interference USB-A cable-1 BT Antenna-1 User Manul-1 Bluetooth 5.0 Input Bluetooth 5.0 Input, longer transmission distance, works with iPhone, Android, Smartphones, iPad, Tablet PCs etc. In the process of using Bluetooth input, more music details are retained, making the music more delicate and soft. Switch to the BT position, search "SMSL BT5.0C", and pair it easily. Note: If you want to use another device for Bluetooth connection, please turn off your previous Bluetooth device first. Or please use a thin object such as a toothpick to press the button in the "Bluetooth Clear" hole on the back panel for 1 second to clear the bluetooth memory before pairing with other devices. USB audio input support U disk playback USB audio input and support for driver-free use, easily connect the tablet and computer etc. U disk playback: Turn the input selector switch to the USB position, insert the USB flash drive into the USB interface, and A12 will automatically play the audio files in the USB flash drive. Support audio format: MP3 , SBC , WAV , FLAC*(note) Convenient switching Easily turn on/ off the power. Switch input: you can switch USB input to Bluetooth and RCA inputs easily, and freely switch between Bluetooth and RCA inputs. When you switch to USB input from bluetooth and RCA inputs, you may need to re-plug the USB cable or restart the amplifier. That is determined by the chip, since the chip has priority functions. EQ Controls Bass & treble adjustments are ±12 level, perfect knob texture, every time you use the knob, you will feel a strong sense of damping，more stable than remote control. When the bass and treble knobs are adjusted to the 12 o'clock position, the bass and treble are not adjusted. Aluminum CNC processing All aluminum alloy CNC precision processing shell, anodizing technology and chamfering process, exquisite workmanship and delicate touch. 0.005% Low distortion New technology class D power amplifier chip, higher quality, efficiency up to 92%, further reducing power consumption. THD+N: 0.005%. Sepcification Inputs ：Bluetooth 5.0, RCA , USB THD+N: 0.005% SNR: 102dB Channel separation: 98dB Output Power: 80Wx2(4Ω) / 40Wx2(8Ω) Input sensitivity/input impedance: 190mV / 40kΩ Power Consumption: 35W(Normal Volume) Size: 5.47x5x1.38 inches (WxHxD) Amplifer Weight: 382 g Support U disk playback Support audio format: MP3 , SBC , WAV , FLAC*(note) Note: The two specifications of WAV and FLAC must use a USB flash drive with a higher transmission speed because of the higher transmission bit rate, otherwise it may cause the music playback to be interrupted.The U disk only supports FAT and FAT32 formats, and the maximum support is 64G. And the order is arranged according to the time when they are stored in the USB flash drive.