1. Use M65831AP and NE5532 2. The Electrolytic Capacitor Signal Main Circuit, The Main Filter Capacitor Adopts Erkan Capacity 2x3300uF, And Adopts 5A And Above Rectifier To Ensure Strong And Continuous Power Support. 3. The Use Of High-Precision Chip Resistors Ensures A Good Signal-To-Noise Ratio Of The Whole Machine. 4. The Pcb Uses 1.6mm Thick Double-Sided Sheets, 2.0A ± Copper Thickness, And Full Tin Spraying Process To Ensure Good Passing Performance Of Large And Small Currents. Top-Notch Pcb Quality. 5. The OK Input Operational Amplifier Uses Ne5532 For Amplification, The Output Uses Double-Precision NE5532, And The Karaoke Core Uses Mitsubishi M65831, Which Has Good Analytical Power And Natural And Delicate Sound. There Is Also A Reverberation Delay Adjustment On The Board. Input Voltage: AC12V-15V Dual Voltage Potentiometer Functions From Left To Right: OK1, OK2 Reverberation Depth Music Volume The Switch Is Delayed Adjustment Note: Different Batches May Have Differences In Product Appearance, Color, And Printed Characters, Which Will Not Affect The Use Colour:As Shown Material:PCB Package Contents: 1 x Front Level Board Module Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.