Features: Overall architecture: NE5534 front-end amplifier+OP07 DCservo+C1237 speaker protection+TDA7293 back-end amplifier, reasonable architecture, excellent sound quality, stable and reliable operation. The maximumpower depends on the power supply voltage and horn impedances, THD=10%, RL=82 VS=40V; If it is a 42 load, please do not exceed the double AC20V transformervoltage to avoid unnecessary losses; Please pay attention to monitoring the temperature of the heat sink during use. If necessary, it is recommended to use a fan to assist in heat dissipation; Pre amplifier 5534 may have brands randomly shipped with the same sound quality. If there are special requirements, please raise them in advance to avoid disputes; Specifications: Overall architecture: NE5534 front-end amplifier+OP07 DCservo+C1237 Speaker Protections+TDA7293 back-end Amplifier Power supply voltage: AC12-28Vx2 (dualAC) Power supply: recommended above 200W Output power: 100Wx2 Output impedances: 4-16ohms Channel: 2-channel stereo Circuit architecture: TDA7293+OP07+NE5534 Feature: Front stage stabilizedDC servo delay protections Protections feature: overheatDC short circuit protections Size: approx 149.6x135x52mm/5.89x5.31x2.05in Note: Due to the different monitor and light effect, the actual color of the item might be slightly different from the color showed on the pictures. Thank you! Please allow 1-2cm measuring deviationdue to manual measurement. Package includes: 1PC Stereo HighPower 2.0 Power Amplifier Board