These professional amplifiers are class AB digital amplifiers with switching power supply, using a special circuit design techniques, focusing on the stability of the products in the long-term continuous full power conditions, improving the protection function to avoid damages caused by operation mistakes and embarrassments caused by error protection. The main components of the PCB board using SMT technology manufacturing and through computer simulation aided design circuit layout, so that the amplifier has a high signal to noise ratio and anti-jamming capability. These amplifiers have a higher damping and perfect filtering system, so that the high frequency is more delicate and soft, low-frequency is more powerful. And small size with light weight is more convenient to use.