Where does Jingmei’s voice come from? Knowledge exploration of power amplifier sound
The function of power amplifier is commonly known as “amplifier”. The role of a good sound system amplifier is indispensable.
According to the different components used, the power amplifier has “tube amplifier” [tube power amplifier], “stone machine” [transistor power amplifier], “IC power amplifier” [integrated circuit power amplifier]. In recent years, due to the use of new technologies and new concepts in tube amplifiers, the electronic tube, an ancient vacuum device, has become brilliant again, and its beautiful sound has made many enthusiasts bow down. Senior enthusiasts almost have one. “IC power amplifier” is rarely seen in HI-FI power amplifiers because its tone is not comparable to the two power amplifiers.
“Professional power amplifier” is generally used for the amplification of conferences, performances, halls, halls, venues, and halls. The design is based on high output power, perfect protection circuit and good heat dissipation. Most of the “professional power amplifier” tones used for HI-FI playback, the sound is hard and unpleasant.
The detailed classification of “civil power amplifier” includes “HI-FI power amplifier”, “AV power amplifier”, “KALAOK power amplifier” and the so-called “comprehensive power amplifier” which integrates various commonly used functions.
“HI-FI power amplifier” is the power amplifier of our enthusiasts, and its output power is generally less than 2X150 watts. The design is based on the tenet of “beautiful sound and high fidelity”. Various high and new technologies are concentrated in this kind of power amplifier. Prices also range from a thousand yuan to several hundred thousand yuan. “HI-FI power amplifier” is divided into “split type” [separate the preamplifier], and “integrated” [integrate the preamplifier and the rear machine]. Generally speaking, in the same grade of models, the “split type” is higher than the “combined machine” in terms of signal-to-noise ratio, channel division and other indicators [not absolute]. And it is easy to compare the sound through the signal line. The combined machine has the advantages of being easy to use and relatively low in cost. The output power of the cheap combined machine is generally designed to be less than 2X100W, and many manufacturers produce high-end combiners with 2X100W or more.
“AV amplifier” is a dark horse that has been out of control in recent years. With the popularization of large-screen TVs and various image carriers, people’s demand for “sit at home and watch movies” is increasing day by day. Therefore, a multi-functional power amplifier integrating various audio and video functions came into being. “AV” is the acronym for AODIOVIDIO in English, that is, audio and video. From its birth to the present, “AV power amplifier” has gone through the process of Dolby Surround, Dolby Pro Logic, AC-3, and DTS. The difference between AV power amplifiers and ordinary power amplifiers is that AV power amplifiers have AV selection Dolby Pro Logic decoders. AC-3, DTS decoder, and five-channel power amplifier. As well as the finishing touch of the digital sound field [DSP] circuit, it provides different sound field effects for various program playback. However, because the AV power amplifier has undergone too many and complex processing circuits in the signal circulation link of the circuit, the purity of the sound has been “colored” too much, so the effect of using the AV power amplifier to be compatible with HI-FI playback is not good. Ideal. This is also the reason why many HI-FI enthusiasts dislike AV power amplifiers.
“KALAOK power amplifier” is also a kind of power amplifier developed in recent years. The difference between it and ordinary power amplifiers is that “KALAOK power amplifier” has The reverb has developed from the BBD analog reverb in the past to the present DIGETAL digital reverb], pitch changer, microphone amplifier. In recent years, some manufacturers have combined various functions including AV amplifier and KALAOK amplifier into one for the needs of the market. The so-called “integrated power amplifier” is a hodgepodge of power amplifiers. It has everything and can’t do anything well. It is a rural-oriented power amplifier.
As the name suggests, “special power amplifier” is used in special occasions. power amplifiers, such as sirens, low-voltage power amplifiers for cars, etc., will not be introduced here.
The main performance indicators of the power amplifier:
The main performance indicators of the power amplifier Performance indicators include output power, frequency response, distortion, signal-to-noise ratio, output impedance, damping coefficient, etc.
Output power: the unit is W. Due to the different measurement methods of various manufacturers, there are some Different names. For example, rated output power, maximum output power, music output power, peak music output power.
Music power: It refers to the condition that the output distortion does not exceed the specified value. The instantaneous maximum output power of the signal.
Peak power: refers to the maximum music power that the power amplifier can output when the volume of the power amplifier is adjusted to the maximum under the condition of no distortion.
Rated Output power: The average output power when the harmonic distortion is 10%. Also known as the maximum useful power. Generally speaking, the peak power is greater than the music power, and the music power is greater than the rated power. Generally speaking, the peak power is 5 of the rated power. –8 times.
Frequency response: Indicates the frequency range of the power amplifier and the unevenness within the frequency range. The flatness of the frequency response curve is generally expressed in decibels [db]. Home HI-FI The frequency response of the power amplifier is generally 20HZ–20KHZ plus or minus 1db. The wider the range, the better. The frequency response of some top power amplifiers has been 0–100KHZ.
Distortion: The ideal power amplifier should be After amplifying the input signal, it is faithfully restored without any change. However, due to various reasons, the amplified signal of the power amplifier is compared with the input signal, and often produces different degrees of distortion. This distortion is distortion. Expressed as a percentage, its The smaller the value, the better. The total distortion of the HI-FI power amplifier is between 0.03%–0.05%. The distortion of the power amplifier includes harmonic distortion, intermodulation distortion, crossover distortion, clipping distortion, transient distortion, Transient intermodulation distortion, etc.
Signal-to-noise ratio: refers to the various The ratio of the noise level to the signal level, expressed in db, the larger the value, the better. Generally, the signal-to-noise ratio of household HI-FI power amplifiers is above 60db.
Output impedance: The equivalent internal resistance presented to the speaker is called output impedance.
A good performance index of a power amplifier does not necessarily prove that it has a good tone. This is what beginner audiophiles must realize. This is also the pursuit of many enthusiasts. So for the power amplifier, we need to know more and understand its inner ability to use the power amplifier better.
