Amplifier commonly known as "amplifiers", the role is from the signal source of the weak signal amplification, to promote the speaker sound. Measure the performance of a power amplifier, there are many ready-made standards, such as output power, frequency response, distortion, signal to noise ratio, output impedance, damping coefficient. Before identifying the amplifier, it is best to understand what these indicators specifically refer to.

1, the music power, that output distortion does not exceed the specified ＆#118alue of the conditions, the amplifier on the music signal instantaneous maximum output power. Usually manufacturers to long-term power or rated power for the speaker's marked power.

2, the peak power, that is, without distortion conditions, the amplifier volume to the maximum, the amplifier can output the maximum music power.

3, rated output power, also known as the maximum useful power, when the harmonic distortion when the average output power of 10%. Typically, the peak power is greater than the music power, the music power is greater than the rated power, the peak power is 5 times the rated power.

4, the frequency response, refers to the constant voltage state, the power amplifier frequency range and frequency range of unevenness. The degree of straightness of the frequency response curve is expressed in decibels [db]. Amplifier frequency response of the wider the better, generally between 20Hz - 20KHZ ± 1db, some Need for power amplifier or even to 0--100KHZ.

5, the distortion, the amplifier to amplify the sound signal, due to various reasons often have different degrees of distortion distortion, this distortion can be divided into harmonic distortion, intermodulation distortion, cross distortion, clipping distortion, transient distortion, Transient intermodulation distortion, etc., we usually say that the distortion is total harmonic distortion. Distortion is expressed as a percentage, the smaller the ＆#118alue, the better. The total distortion of the general amplifier is between 0.03% and 0.05%.

6, the signal to noise ratio, refers to the speaker playback of the normal sound signal and no signal when the noise signal (power) ratio, expressed in dB. The greater the ＆#118alue of the better, the general amplifier signal to noise ratio in more than 60db. Distortion and noise there is a certain relationship, the difference is that the distortion is regular, and noise is no law at all.