FAQ

A quels paramètres faut-il faire attention lors de l'achat d'un amplificateur ?

: 4940

: 2021-12-29 12:06:46

A qualified professional power amplifier often reaches the corresponding technical parameters. The following 8 technical indicators cannot be ignored！

1. Power Band Width  : The frequency response range is 20Hz ~ 80KHz, and the frequency response of the speaker from bass to treble correspondingly requires a response capability in the range of 20Hz ~ 20KHz. As the "bottleneck" component of signal transmission, the power amplifier requires a wider frequency response, such as 7Hz ~ 80KHz, in order to ensure the integrity of the signal.

2. Signal To Noise Ratio  : This is the parameter that most directly reflects the quality of the power amplifier. It is generally above 80dB. High-quality products often reach 105dB or more. If you are pursuing pure sound quality, then this The value cannot be ignored.

3. Distortion (THD)  : This can be discussed together with the other two important indicators of the power amplifier, "Rated Power" (Rms) and "Maximum Power" (Peak Power). When a power amplifier works at its Rms power, the distortion should be relatively small, generally in the range of 0.5% to 0.01%. When peak power or bridge connection, the signal may produce distortion, clipping (incomplete broadcast signal) and other distortions, and the distortion ratio will increase accordingly. About 0.5% to 1% is normal. The smaller the distortion ratio, the better the sound effect, which is also an important indicator to measure an amplifier.

4. Input Sensitivity  : This is the adjustment level set for different manufacturers, different brands of mainframes and pre-level audio sources. The range is from 100mv to 4V or even higher. The tuning must match the audio source.

5. Input Impedance  : Generally, the input impedance of the power amplifier should be high and the output impedance should be low. The higher the input impedance, it can block all kinds of noise more effectively, and the common value is 10KΩ or higher.

6. Load Impedance  : Household power amplifiers are generally 8Ω/4Ω; car power amplifiers are 2Ω to 8Ω when stereo; and 4Ω to 8Ω when bridged. However, some specially designed power amplifiers can have an impedance as low as 0.1Ω, which has extraordinary capabilities. At this time, a power amplifier can be connected to dozens of woofers in parallel to create an ideal sound pressure level (sound pressure refers to the pressure of the sound on the human ear. It is a measure of the ability of the sound system, because the higher the sound pressure, The higher the requirements for the system. The highest record in China is 141.5dB, and the record abroad is 176.5dB). Just like those vans with dozens of woofers in the car that can smash the glass, but this situation may only be seen during audio competitions.

7. Working voltage : Car audio generally works within the range of 10V ~ 15V.

8. Damping Factor  : This factor is calculated from the output impedance of the rated load (4Ω). It is generally believed that the smaller the output impedance and the higher the damping factor, the better the power amplifier. In fact, the ratio of high-quality power amplifiers is mostly above 50, and some even exceed 500, although some experts believe that a damping coefficient of about 50 is sufficient. But based on empirical judgment, if the coefficient is high, the wire requirements can be relaxed. In contrast, too high a coefficient will affect the timbre, but it is helpful for bass performance.

9. Slew Rate  : The highest amplification stage of the power amplifier per unit time can amplify a strong signal excitation into high-voltage, high-current AC audio. The high-end models are above 30V/us, and some exceed 50V/us. The ratio is high, the conversion ability is good, and the level and dynamics of the music can be restored and reproduced closer to the original sound when combined with the speakers.

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