How to use the power amplifier?

　　In a set of speakers, the effect of the power amplifier is to expand the input signal of the pre-expander and then output it to the speaker of the speaker. During this process, the power amplifier will also perform some protective processing on the input signal to ensure that the input signal is satisfactory and pure. When buying a power amplifier, assuming there is no senior audiophile accompanying it, you can only rely on your own choice or listen to the salesperson's introduction. When you ask to play a piece of music for trial listening, the salesperson will usually selectively put some music that is suitable for playing on this amplifier, making it difficult for you to distinguish the pros and cons of the power amplifier function. , no longer have to move machines blindly.

　　Output power: The output power needs to be discussed in conjunction with the impedance of the speaker. Speakers with different impedances will have different output powers. For example, when the speaker is 4 ohms, the output power with no distortion or minimal distortion is 100W, then when the speaker is 8 ohms, the output power with no distortion or minimal distortion is only about 50W. The other one is to combine your own needs. The use of 30W in the room is completely satisfactory, and the living room generally 60-80W can also meet the needs. In order to reduce the distortion during high-power output and obtain better results, the output power should have a certain reserve, and choose a slightly larger one.

　　Frequency response: Whether frequency response meets the minimum requirements of music: We know that music has high, medium and low sounds, and the Z treble of some musical instruments is often above 4KHz. In addition to the high-order harmonics of these trebles, the demand is very high. frequency. Some instruments only need less than 20Hz when low frequency, which requires the frequency response of low frequency to reach below 20Hz. Moreover, this is only a musical requirement, assuming that considering the acoustic effects of the natural world, the frequency response plan is much larger. Generally speaking, the frequency response of most high-end power amplifiers is between 10Hz--70KHz.

　　Dynamic response: Dynamic response detects the ability of the power amplifier to process strong and weak signals. When playing a piece of music or singing a song, it only needs a few dB when the sound is small, and it can reach more than 90dB when the sound is loud. When the power amplifier processes extra large or extra small signals, other functions tend to decline, which requires a larger dynamic planning to maintain other functions under extreme conditions. Therefore, the dynamic planning of the power amplifier requires at least 5-100dB. .

　　Signal-to-noise ratio: The signal-to-noise ratio, such as a needle, must reach the largest possible ratio, that is to say, the noise will reach the smallest limit compared with the signal sound, for example, it is so quiet that a needle can be heard when it falls on the ground. This policy can be distinguished by oneself during the audition, reduce the sound source to the smallest or pause, the distance between the person and the speaker is one meter, and the volume of the power amplifier is adjusted from the small to the largest. It is better to clarify the signal-to-noise ratio of the power amplifier. The signal-to-noise ratio of some high-end power amplifiers has reached more than 105dB, and the function is appropriate and good, and basically no noise can be heard.

　　In addition to the above parameter guidelines for reference, professional power amplifiers also have some unreasonable identification methods. For example, in terms of weight, the power amplifier needs a certain tonnage to have a good anti-vibration effect. In order to ensure the power, the transformer must be made larger, which is naturally very heavy. There are still many professional identification methods for power amplifiers. Knowing some of the above parameters and value selection planning will at least not be at a loss when purchasing.

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