2. Fixed resistance amplifier impedance amplifier such constant load requirements, when the input signal a certain time, changes in the output voltage as the load changes occur is very large. Because this type of amplifier within the amplifier with a deep negative feedback device, this deep negative feed back amount is generally 10 ~ 20dB above audio amplifier, therefore, the amplifier output impedance is low, the load within a certain range, the output voltage can still maintain a certain value, the sound quality can be maintained. In terms of load amplifier brand, like a "boom" in pushing a "boom" in pull together to complete the current output tasks. Although Class A push-pull amplifier can be enlarged, but more common is constituted by a push-pull amplification B or class AB amplifier. By type amplifier tube power amplifier is different, it can be divided into tube amps and stone. Danji is using a tube amplifier. Stone is using a transistor amplifier. According to different functions can be pre-amplifier (also known as a first stage), power amplifier (also known as the post-stage) with integrated amplifier amplifier brand, Wuhan Jiuhua video (certification), the amplifier is provided by Wuhan Engineering Co., Ltd. Jiuhua video. Video Jiuhua Wuhan Engineering Co., Ltd. (www.jowa-tech.com) is a leader in Wuhan, control and adjustment of the equipment, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs . Jiuhua video in Wuhan leadership with the staff warmly welcome all inquiries negotiations to create video Jiuhua Wuhan better future.