Feature●The amplifier dynamics are about 100 times, the capacitor is about 22 times and the music part is about 5 times. Mixed output can drive the earphone. Input Voltage * Please note that magnification signal cannot be higher than the supply voltage. Please choose the power supply voltage logically. The higher the voltage, the larger the signal. Cutting is not easy. If the signal is not too big, it will work even if the voltage is low●This is not a power source that is prone to hum, so please use a high quality, low ripple power supply●The power interface is DC5.5 x 2.1, internal+external-power supply not included●Speaker connection method: AUXDescription Bumdenuu Color: Black Material: Plastic Package Contents: 1 * MA-2S audio preamp package contents above and other products are not included here. Note: The color and size of the actual item may vary slightly from the color and size on the website due to lighting and display conditions. The margin of error for the measurement is 0.4 - 1.2 inches (1