1. A970/C2240 high voltage audio pair tube dual differential circuit and A1145/C2705 for voltage amplification 2. Promote the use of medium-power pair tube A1837/C4793, and the output stage uses A1943/C5200 high-power 3. for controls. Wide power supply range, DC plus or minus 20V-90V is acceptable, as long as sufficient power is supplied 4. Easily reach 200W, the sound quality is good, the driving force plate is strong, and the 15-inch speaker can be pushed without any pressure! 5. Need A Professional To Install The Corresponding Accessories To Avoid Damage To The Accessories :Undistorted Power 200W (Maximum Power 300w) Note:Different Batches May Have Differences In Product Appearance, Color, And Printed Characters, Which Will Not Affect The Use. Colour:As Shown Material:PCB Size:Power Amplifier Board Size:About 120x60x45mm (Length x Width x Height) Package Contents: 1 * Amplifier 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.