Features 1.Two Channel Design: This microphone preamplifier board adopts two channel design, suitable for single lithium battery powered. 2.One Channel: If only used one channel,the other channel needs to short circuit the input with GND, to avoid interference with the signal crosstalk. 3.AD828 Chip: This microphone preamplifier board adopts AD828 fever op amp chip,suitable for low voltage power supply (3.8‑15V). 4.Stable Performance: This microphone preamplifier board is made from premium plastic material, which ensures stable performance. 5.Practical Accessory: This microphone preamplifier board is suitable for guitar, erhu and other musical instruments. Specification Item Type: Amplified Board Module Material: Plastic Product Model: AD828 Working Voltage: DC3.8V-15V Power Supply: 3.8-15V Lithium Battery or Linear Power Supply (Battery Not Included) Board Size: Approx. 25 x 16mm / 0.98 x 0.63in Package List 1 x Amplified Board Module