Americans in 1906, forrester invented the vacuum triode, created the human electroacoustic technology. Was invented by bell LABS in 1927 negative feedback technology, make sound technology development has entered a new era, is a representative, such as the Williamson amplifier is successfully using negative feedback technology, make the distortion degree of the amplifier is reduced greatly. In the 1950 s, the development of the vacuum tube amplifier reached a climax period, all kinds of vacuum tube amplifier emerge in endlessly. Due to the vacuum tube amplifier tone color, fruity, sweet still preferred by enthusiasts. The emergence of a transistor in the 1960 s, make broad audio enthusiasts entered a wider sound of heaven and earth. Transistor amplifier has the exquisite and touching tone, low distortion, wide frequency response and dynamic range, etc. In the early 1960 s, American new members of the first audio technology, integrated circuits, in the 70 s, the integrated circuit for its high quality and low price, small volume, function etc., gradually by the audio industry. Development up to now, the thick film sound integrated circuit, operational amplifier IC is widely used in audio circuit.
2, the mid - 1970 - s
Japan produced the first power field effect tube. Because the power field effect tube at the same time has pure and sweet sound tube as well as the dynamic range of up to 90 db, THD < 0.01% (100 KHZ), the characteristics of quickly became popular in the world of sound. Nowadays many of the amplifier is adopted in field effect tube as the final output. Usually told by the kinds of family music center combined sound have desktop music center and console audio system two kinds big. Due to the audio system has a higher sound quality, so it's two speakers average volume is bigger. Edit this paragraph 2, the host has a body and layered structure of acoustics of two categories. In the integration of the combined sound, it's all part of the circuit (including record player) in a shell, this structure is generally used in the combination of low sound. In the layered combination of sound, depending on the grade of the machine by the number of layers is different also. Stratification is more of the combination of acoustics, record player, CD player, a layer of a layer, tuner layer, double card playback sound tones of a layer, controller layer of a layer, the main power amplifier. In hierarchical less combined sound, the record player, CD player, each layer and the other to one layer. Miniaturization, digitalization, specialization, film and television is the inevitable trend of the development of home electronics.
1, miniaturization acoustics
Miniature desktop music center has a long history, more than 10 years ago has been advanced subminiature combined sound. But as a result of listening speakers, stereo gramophone, recording booth is not very good solution, so has been stay on the lower class. In order to create a small sound world, not only from the amplifier, control parts, left and right speakers, have to from the aspects of the tuner, CD player and recording booth together. Digital audio. Digital technology is a new technology, so the digital audio development in solving the problem of distortion of simulation of the acoustic noise. Sound using the digital technology, digital signal from the sampling frequency to the quantitative characteristics of records, has a clear resolution, no color dithering, get the image is very clear. And you can swap and the upper machine, the analog playback as equipment cannot match. Digital recording can take time