Amplifier is the abbreviation of power amplifier, which is designed to amplify the weak music signal read by the sound source to promote the sound of the speaker. Classification from components can be divided into: tube amps and transistor amplifiers. The working principle can be divided into three categories: Class A, Class A and Class B. In theory, the harmonic distortion of Class A power amplifier is very small, so the fidelity is quite high. The fidelity of Class A and Class B amplifiers is lower than that of Class A. If the production process is high, high fidelity can be achieved.
The distortion of the power amplifier is an undesired waveform change in the output signal waveform, causing sound distortion, mainly harmonic distortion, intermodulation distortion, transient distortion and phase-to-distortion distortion.
Harmonic distortion, also known as harmonic distortion, refers to the extra harmonics of the sound after playback of the audio equipment than the original sound source signal. The defect of the negative feedback network or the nonlinearity of the power amplifier can cause harmonic distortion. The sum of the harmonic values ​​of the harmonics is expressed as a percentage of the original signal strength. The harmonic distortion of a high-fidelity amplifier should be less than 0.6% in the full-range range, otherwise the sound will sound dry and hard. Generally speaking, 1000HZ is the frequency with the smallest distortion of the power amplifier. Many manufacturers regard the distortion of this frequency as the standard, which is not comprehensive. Welcome to China Home Theater Network
Intermodulation distortion is a phenomenon in which a new nonlinear signal is generated after two amplitudes are transmitted through a sound device in a certain ratio (often a 4:1 mixed high and low frequency signal). The rms value of the nonlinear signal is always expressed as a percentage of the amplitude of the original high frequency signal. Usually, the intermodulation distortion of most power amplifiers is slightly larger than the harmonic distortion. For high-fidelity power amplifiers, the intermodulation distortion should not be much larger than the harmonic distortion, preferably no more than 10%. When the harmonic distortion is less than a certain value, the fidelity of the signal depends largely on the intermodulation distortion.
Transient distortion, also known as transient response, usually with an input square wave signal or a sinusoidal wave train with a square envelope (breaking sounds, such as explosions, gunshots, drums, etc.) after passing through the audio device, its waveform Maintain shape ability. Transient distortion has transient intermodulation distortion and low conversion rate distortion. The transient intermodulation distortion is caused by the negative feedback design of the power amplifier or the improper working point of the class A power amplifier. Usually, the transistor power amplifier uses large loop depth feedback. In this case, a signal must be amplified by the power amplifier and then fed back to the input. Due to the "time difference", the two waveforms are inconsistent (in theory, they should be consistent), resulting in intermodulation. distortion.
The transient distortion caused by the low conversion rate is due to the rapid change of the power amplifier and the "reactive slow" phenomenon. In general, the conversion rate of the power amplifier is preferably not less than 20V/us (that is, the voltage is increased from 0 to 20V in 1 microsecond, and the high-quality power amplifier can reach 100V/uS).
Judging from the hearing, transient distortion will make the high-frequency resolution of the sound worse, affecting the clarity of the sound, making the music lose its transparency and the sound image is blurred. Phase distortion refers to the distortion caused by the time relationship after the signals of different frequencies are reproduced. In the case of music replay, phase distortion will directly affect the quality and orientation of the “sound imageâ€, so you must pay attention to the quality and orientation of the “sound image†when purchasing the amplifier.
The noise of the sound system generally comes from two parts. One is caused by interference outside the system, and the other is generated internally by the system, that is, the noise generated by the various components that make up the system itself. After the external noise is removed, the internal noise of the system is particularly important. Usually the noise level of the power amplifier is usually expressed as the logarithm of the maximum level of the signal and the noise level ratio. The ratio is called "signal-to-noise ratio", abbreviated as S/N or SNR, referred to as signal-to-noise ratio. Most high-quality amplifiers have a signal-to-noise ratio of more than 90dB.
The speaker looks simple, but it reflects the extremely high acoustics. A famous brand of speakers not only reflects the deep acoustics, but also exudes a strong national atmosphere. From these aspects, the difference between Chinese speaker manufacturers and some foreign speaker factories is far away. There are even many manufacturers who sell sheep's heads and sell them. If Chinese speakers want to catch up with foreign famous brand speakers, it is a long way to go.
Our company specializes in the production and sales of all kinds of terminals, copper terminals, nose wire ears, cold pressed terminals, copper joints, but also according to customer requirements for customization and production, our raw materials are produced and sold by ourselves, we have their own raw materials processing plant, high purity T2 copper, quality and quantity, come to me to order it!
Cable Terminals
Taixing Longyi Terminals Co.,Ltd. , https://www.lycopperlugs.com