1. The board is a single-channel amplifier board, which requires dual-channel2. The circuit design uses A970/C2240 high-voltage audio pair tube dual differential circuit and A1145/C2705 for voltage amplification to promote the use of mid- pair tube A1837/C4793, and the output stage uses A1943/C5200 high- pair tube.3Wide supply range, DC plus or minus 20V-90V can be, as long as enough is supplied to easily reach 200, the sound quality is good, the driving force is strong, and the 15-inch speaker is pushed without pressure 4. supply: dual voltage, DC plus or minus 20-90V (the upgraded version has optimized the circuit and parts, but To directly apply high voltage, it is recommended to use below 90V, do not challenge the voltage limit. )5. Real : undistorted 200W, maximum 300W.size:120 x 60 x 45MMMaterial:abscolour:blackPackage Contents:1 x amplifier boardOnly the above package content, other products are not included.Note: Light 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.