Note: The on-board resistor R5 is adjusted by the magnification. If the magnification is not suitable, the resistance of R5 can be adjusted. It can be selected from 5k to 150k. The larger the resistance, the higher the magnification. If the plug-in resistor is used, the original chip resistor can be removed, and the plug-in resistor is soldered to the reserved pad on both ends of the original chip resistor. We highly appreciate all customers opinions to improve the selling, also if anything you unsatisfied, please contact us for probable best solution. Package Includes: 3pcs

Size:2.5x1.6cm/0.98x0.63inch. Working voltage:DC3.8V-15V.This microphone amplifier board without power regulator circuit,can only use the battery or linear power supply,can not use switching power supply,otherwise there will be interference. If you only used one channel,the other channel needs to short-circuit the input with GND,To avoid interference with the signal crosstalk. Ultra-small volume dynamic microphone preamplifier board,two-channel design,suitable for a single lithium battery-powered,using AD828 fever op amp chip,suitable for low voltage power supply (3.8-15V). The piezoelectric ceramic piece is sensitive to the sound wave vibration transmitted by the solid, and is not sensitive to the acoustic vibration of the gas, which can effectively reduce the environmental noise and avoid the whistling caused by the self-excitation. Can be used for guitar, erhu and other musical instruments.