The development history of sound technology can be divided into four stages: tube, transistor, integrated circuit and field effect transistor.

In 1906, American de Forrest invented vacuum transistor, which pioneered human electro-acoustic technology. Bell Labs was invented in 1927. After the negative feedback technology, the development of audio technology has entered a new era, such as Williamson amplifier has successfully used the negative feedback technology to greatly reduce the distortion of the amplifier to the 1950s, the development of the tube amplifier reached one of the most exciting periods, a variety of tube amplifiers emerge in endlessly. Because the sound color of the tube amplifier is sweet and round, it is still preferred by enthusiasts.

In the 1960s, the emergence of transistors made the vast number of audio enthusiasts enter a broader audio world. Transistor amplifiers have the characteristics of delicate and moving timbre, low distortion, wide frequency response and dynamic range.

In the early 1960s, the United States first introduced integrated circuits, which are new members of audio technology. In the early 1970s, integrated circuits were gradually recognized by the sound industry because of their high quality, low price, small volume, many functions and so on. Up to now, thick film audio integrated circuits and operational amplifier integrated circuits have been widely used in audio circuits.

In the mid-1970s, Japan produced the first field effect work recommendation tube. Because the field effect power tube has the characteristics of pure electron tube, thick and sweet tone color, and dynamic range of 90 dB, THD < 0.01% (100KHZ), it soon became popular in audio. In many amplifiers today, field effect transistors are used as the final output.

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