In 1906, American De Forest invented the triode, creating the first human electroacoustic technology. In 1927 Bell Laboratory invented the negative feedback technology, so that the development of sound technology into a new era, more representative such as Williamson amplifier, more successfully used the negative feedback technology, so that the distortion of the amplifier greatly reduced. In the 1950s, the development of vacuum tube amplifiers reached a climax, and various vacuum tube amplifiers emerged in endlessly. As a result of electron tube main technical index amplifier tone is sweet, round, still be up to now enthusiast place preference.

The transistor

The appearance of 60 time transistor on the last century, made the vast number of audio lovers into a more extensive audio world. Transistor amplifiers have exquisite and moving timbre, low distortion, wide frequency response and dynamic range.

The integrated circuit

At the beginning of 60 time on century, the United States rolls out the new member in acoustics technology above all -- integrated circuit, arrived at the beginning of 70 time on century on century, integrated circuit with its quality and low price, small volume, function many wait for characteristic, be recognized by acoustics circle step by step. Up to now, thick film audio integrated circuit, operational amplifier integrated circuit is widely used in audio circuits.