【 Weak current College 】 all kinds of power amplifier characteristics

Various characteristics of the power amplifier
Power amplifier or amplifier, it can be said that the various types of audio equipment in the largest of the family. The brand, model number, it is too numerous to mention. Although it is called a power amplifier, but its main purpose, the amplifier can be divided into two main categories, this is a dedicated amplifier and an amp. In the stadium field, theater, dance halls, conference rooms, auditoriums, public places, as well as audio listening, and so force amplifier, generally in its technical parameters often there will be some unique requirements, this type of amplifier is usually called a dedicated amplifier or amplifier.
And for the family of Hi-Fi music appreciation, the AV system playback, as well as karaoke entertainment power amplifier, usually we called the civil power amplifier or home amplifier.
Dedicated amplifier and an amp despite some characteristic parameters vary, but it's hard to say there is a distinct boundaries, such as for music recording, listening power amplifier is likely to be one available for home Hi-Fi or even Hi-end amplifier.
Hi-Fi amplifier and AV amplifier
Hi-Fi amplifier and AV amplifier is the household power amplifier in two main categories. These two types of power amplifier is used for different purposes, the focus on design. Hi-Fi amplifier to enjoy music, consumers seek is as "authentic". And AV amplifier users seek is in line with the picture of the "onsite" effect, even exaggerated "on-site" effect. These two types of power amplifier is a direct comparison is better, such as price with $ $ Hi-Fi amplifier and AV amplifier, the cost of Hi-Fi amplifier input only in the two-channel, while the cost of AV amplifier input you want to take 5-6-channel, also has certain effects processing capabilities. If you only look at its two main channel inputs, certainly less than Hi-Fi amplifier two channel input. The difference between its playback effect is obvious. But neither the Hi-Fi amplifiers or AV amplifier, there is a popularized one with high grade quality and value, such as the Distributor's tenryu AVC-A1-AV amplifier, when used for music playback, the audio will not be more than one $ four, Hi-Fi amplifier.
In General, it is difficult to be able to have a can of Hi-Fi, AV-compatible AV amplifier, AV amplifier balanced Hi-Fi music appreciation are conditional, that condition is users appreciate music requirements and standards, if the consumer is only used to enjoy some leisure, music, or just to be able to hear the rhythm of the music, AV amplifier is easy to meet, but what if the music appreciation have higher requirements, General AV amplifier is difficult to meet.
Transistor amplifier and electron tube amplifier
Appreciation for Hi-Fi amplifier can be divided into transistor amplifier and electron tube amplifier with two broad categories, there are IC before or module circuit of Hi-Fi amplifier, but is now rare.
Transistor amplifier and electron tube amplifier does not exist in the difference between good and bad, just different application of the device (a transistor, a tube), since the two types of devices are different, their physical characteristics of the base and circuit.
Tube current is electronic in a vacuum by electric field force of attraction, sport. While the current transistor is a semiconductor elements of the outer electrons in the electric field strength of transfer location. The physical base of different, resulting in practical application circuit features differently. Relatively speaking, electron tube amplifier operating voltage is higher, but the current relatively small, and transistor amplifier operating voltage is low, the operating current is relatively large.
Tube power amplifier and transistor amplifier sound really has some differences, both in response to transient signal. This difference was adapted to the different categories of music and different music appreciation, so current Hi-Fi amplifier formed a transistor amplifier and electron tube amplifier co-exist. However, if the brand, model number, quantity, the transistor amplifier share remains the absolute is greater than the tube amplifier.
Category b class a power amplifier and amplifier
Transistor amplifier output stage transistor working state, you can do a category a and category b Division. The so-called r, simply enable the output stage transistor in sinusoidal AC signal and negative half week when working online sexual area, while the CPI is the only enable the output stage transistor in sinusoidal AC signal is half a week (or negative half week) work online sexual area. Because the output stage transistor working state, makes the output level of power efficiency (that is, the output amplifier and power consumption ratio). In practical output circuit, CPI's efficiency than the CPI's high efficiency 2-3 times. For example, malanshi PM80 transistor amplifier, in the determination of the power supply condition, when working in Group b with 100W output power, but only 20W.
Class a power amplifier crossover distortion does not exist, and whether or not the actual size of the output power, output level crystal of resistance are constant. While the CPI amplifier will always be a certain amount of crossover distortion (although this distortion may be minimal), in addition, large output output stage transistor resistance is small, but small output output stage transistor resistance is relatively large. These are different, resulting in the sound is also different, class a power amplifier sound relative mode b amplifier, meek, in addition to controlling power with low frequency sound Wong-than group b amplifier is strong, especially in the melody of the song 鰏, AV amplifier is easy to meet, but what if the music appreciation have higher requirements, General AV amplifier is difficult to meet.
Class a power amplifier crossover distortion does not exist, and whether or not the actual size of the output power, output level crystal of resistance are constant. While the CPI amplifier will always be a certain amount of crossover distortion (although this distortion may be minimal), in addition, large output output stage transistor resistance is small, but small output output stage transistor resistance is relatively large. These are different, resulting in the sound is also different, class a power amplifier sound relative mode b amplifier andComparison of gentle, the other words on the speaker's low frequency control force than group b amplifier is strong, especially in small volume bass sense better. Class a power amplifier for these features, makes the class a power amplifier in practice do not require a lot of output power margin, a 20W-30W of class a power amplifier has been able to get most of the speakers contribute quite well.
The previously mentioned a class a power amplifier power efficiency low, this causes a mode a power amplifier work to distribute large amounts of heat. In order to make transistors operating temperature not exceed certain limits, requires a large volume and size of the radiator, which makes reference to the amplifier's volume, weight is relatively large. For example, KRELL's KSD-50S class a power amplifier, output to 50W + 50W, weight but nearly 30Kg, malanshi PM-80 in status of output to 20W + 20W, weight also 13Kg.
Pure after the class amplifier and Mono power amplifier
Common power amplifier are put on the size of the signal of the preamplifier (fore) and power amplifier (after the level) in a case in which this power amplifier is often called "combined amplifier". Merge the power amplifier is an easy to use and better performance to price ratio. But this kind of merge amplifier with it some inherent disadvantages, one of the most well overcome is to the fore and after the level of interference problems. To resolve this issue, so they put the former grade and after the class are done in two cases, this has a pure after the class amplifier. Most of the pure after the class amplifier is a dual-channel architecture forms, but this structure allows for two-channel interference problems is not a very good solution, to resolve two-channel interference between it and the two-channel separate mono plain after the class amplifier.
The power amplifier such chunks divided on the significance of the most important is to improve the quality of the power amplifier, rather than the form. If only in the form of realization of mutual separation, although you can solve the problem, but mutual interference to other parameters are not significant improvement, so that separate the amplifier improve their overall quality is still limited.
Power amplifier with transistors and electron tube Division, there is also the former level transistors and valves. For audio enthusiasts and music lovers, in the selection of the fore and after the class has a variety of combinations, and different combinations and different sound characteristics, which makes users and more choice of space.
After the class with a pure power amplifier with front-level on the merits of the entire sound system affected is relatively large. First of all, it must have a certain quality, or else, purely after the class or Mono's advantages will play out, might even put a bad fore "illnesses" highlight, but the overall sound worse. Again, different fore after the class with its different timbre feature, users can choose according to their preference for different combinations.
For example, a lot of audio and music lovers will enjoy the use of "bile" before and after the stone (i.e. tubes fore, transistor after grade) combinations, think this combo is played after the class power output transistor, the characteristics of the transient response and better appreciate the tube fore sound sweet and mellow "charm". However, this kind of arrangement is not a "golden rule", because specific fore and after the class has its own characteristics, while on tone preference and varies from person to person, the consumer can be based on the specific situation to find out your favorite combinations.
Hi-Fi amplifier should have much greater power output
Hi-Fi amplifier's power output is affected by many factors, first of all, the output power and the matching speaker relations larger, secondly also and amplifier ' quality, then there is the use of the environment, room space volume.
Speakers have a parameter called sensitivity, it is in dB/m • W, the meaning is when the speaker is at the distance of power 1W speakers 1m Department produces sound pressure (dB). If a speaker's sensitivity is 90dB, 1 m Department get 90dB sound pressure 1W of power required to drive. To get the sound pressure 100dB, it is necessary to promote the power of 10W. But if the speaker's sensitivity is 80dB (such as ATC SCM-10) to achieve 100dB sound pressure is needed to promote 100W power. Most speakers of sensitivity about 85dB-90dB, speaker, 10W, there is no distortion of-30W power has been able to have enough sound pressure.
Amplifier's own quality, and the amplifier should have output power relations. Power amplifier parameters is known as the damping coefficient, which is indicated on the speaker control a parameter, but this argument has a moderate range, but also and a specific speaker. In General, if an amplifier's quality is very good, in 30 W output can still maintain its performance parameters in certain standards. There's no need to require amp has greater power output. But if the amplifier's quality is not very ideal, when the output power increased when its deterioration of performance parameters, then you should make the amplifier's power output with some margin to ensure the practical output power still has some good arguments. Typically, when the amplifier output for CPI or tube amplifier, you do not need to have more margin, 20W output power: 30W output power is sufficient. But if the CPI amplifier or poor-quality amplifier, you should make the amplifier output power greater margin. In addition, if the matching speaker is large inverted phase, should enable the amplifier has greater power output. From the amplifier itself quality considering the power amplifier should have output power, the power margin is bigger really selected can improve the power amplifier and speaker adaptation.
Or do you want to clear it, select the output power of larger amplifier main significance, not because we need such big sound pressure, but rather to improve the amplifier to the speaker of the adapter status. If an output power of moderate power amplifier has been able to put the speaker control of handy, there's no need for this amplifier higher output power requirements.
Use of the environment,Is the room space volume and power amplifier power output should be a degree of relationship, the more we are talking about the size of output power, is the room space volume at 40 below, if the room space volume is large, then the power amplifier output power you should increase the number.
Tube power amplifier output stage features
Tube power amplifier power output stage there are three circuit type, a class is output transformers for push-pull output circuit. This type of output circuit type in the tube amplifier accounted for a majority. In push-pull circuit output transformer DC components rarely, second-harmonic distortion is also very small, this type of circuit output power can be relatively large, so the application is relatively large. Generally interested tone on danji of sound fans, this type of output-level danji very well. However this type of amplifier, output transformer design and technology is essential, if the output transformer design and workmanship is inadequate, often this type of amplifier's transient response frequency response, is not very satisfactory. Because the output transformer, so matching speaker adaptation scope is smaller.
Another kind of power output circuit type is a single-ended mode a circuit. This type of circuit also have transformers, but this type of circuit output transformers have great DC components, the requirements of the output transformer than push-pull output circuit output variable requirements. In addition to the requirements of the power supply is also relatively high. This type of output circuit is characterized by more harmonic constituents, even though it is a harmonic distortion, but on the musical signal, the second harmonic is a high degree of consonance audio, sounds very ears. This feature enables the output circuit of the amplifier in the sound of colours is very characteristic, especially when the amplifier level uses triode, vocal sounds sweet, Chamber music in string sounds are very delicate, or rather, this type of amplifier sounds great taste. But this kind of power amplifier output power is not easy to do, so if completed with speaker sensitivity is low, in the air when large orchestral is more narrowly. This type of tube amplifiers are some audio players welcome, often equipped with a high-power transistor amplifier, also has one up PA, I was somewhat complement each other on the timbre, however, this also illustrates this type of amplifier sound characteristics are moving.
There is also a tube amplifier output stage circuitry is OTL circuit, the so-called OTL circuit is no output transformer circuits. Modern transistor amplifier output stage almost all OTL circuit or improved OTL circuit. Tubes and transistor characteristics parameters and working status, transistor amplifier is easy to fit with impedance of 4-8 speaker, but valve power amplifier to unwanted output transformer to fit 4 — 8 speaker will cost some trouble. Valves OTL amplifier as removed output transformer, so in the technical parameters than the previously mentioned the two circuits have greatly improved, this kind of output circuit of amplifier sound very distinctive, and the previous two types of output circuit, it has great momentum and wide sound field, and transistor amplifier compared to it's warm, delicate timbre. This type of amplifier because there is no output transformer, so it can accommodate a wide range of speaker impedance. But the output stage of the amplifier power efficiency, design, technology, testing is more complicated, this kind of output circuit of the amplifier is only found in some high-end models, it is difficult to see the price of standard models.