This Bluetooth power amplifier protects your expensive speakers. High output power, low distortion, and high sound reduction. No noise, interference with current sound. Suitable for home amplifiers or car amplifiers. Features: The power supply delay output protection has no effect on the sound, effectively protecting the speaker unit. High output power, low distortion, no noise, no interference current sound. Support or AC 18V DC 24V power input, dual-mode power supply (rectifier filter circuit required). Multiple audio inputs, onboard Bluetooth receiver module, or input audio from 3P, can accommodate different modules. Use anti-reverse circuit design to avoid using incorrect or damaged power polarity reversal amplifier boards. Supports the bass cutoff frequency (180Hz-250Hz). Specification: Board size: 100 * 92 * 38mm/3.9 * 3.6 * 1.5in Working voltage: DC 22-26V (24V 5-10A recommended) Output impedance: 2-8 ohms for subwoofer, 4-8 Ω for L and R channels Output power: 100W (24V / 3Ω) for subwoofer, 50W (24V / 4Ω) for L and R channels Input impedance: 20kΩ Input signal: 800-1500mV P-P Frequency response: 20Hz-20KHz (±3dB), 20-250Hz (bass) Distortion: bass <10%, L and R channels <1% Bluetooth instructions: Use your mobile phone to search for Bluetooth devices: YJS-68DV4.0, start pairing, enter the pairing password: 5188, it will automatically connect after successful pairing, and the amplifier will automatically transfer to Bluetooth audio, then the phone will sing voice to transmit to the amplifier via Bluetooth, no audio connection line. To use the external signal jack to input an audio source, turn off the Bluetooth switch on your phone or cancel the Bluetooth pairing with the power amplifier board. Package list: 1 * Bluetooth 4.0 Digital 2.1 Class D HIFI Power Amplifier Board Super Bass Note: The measurement allowed error is +/- 1-3cm. 1、The power supply delay output protection has no effect on the sound, effectively protecting the speaker unit. 2、High output power, low distortion, no noise, no interference current sound. 3、Support or AC 18V DC 24V power input, dual-mode power supply (rectifier filter circuit required). 4、Multiple audio inputs, onboard Bluetooth receiver module, or input audio from 3P, can accommodate different modules. 5、Use anti-reverse circuit design to avoid using incorrect or damaged power polarity reversal amplifier boards.