1. Use M65831AP and NE5532 2. The Electrolytic Capacitor Signal Main Circuit, The Capacitor Adopts Erkan Capacity 2x3300uF, And Adopts 5A And Above Rectifier To Strong And Continuous . 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 Good Passing Performance Of Large And Small Currents. Top- Pcb Quality. 5. The OK Input Operational Amplifier Uses Ne5532 For Amplification, The Output Uses Double-Precision NE5532, And The Karaoke Core Uses 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.