Requirements regarding audio power and audio fidelity of recent speakers and home theater systems are constantly growing. At the center of these systems is the music amplifier. Recent power amplifiers have to perform well enough to satisfy these ever increasing demands. There is a huge amount of amplifier designs and types. All of these differ regarding performance. I am going to explain some of the most popular amplifier terms such as "class-A", "class-D" and "t amps" to help you figure out which of these amplifiers is ideal for your application. In addition, after reading this guide you should be able to understand the amp specifications that suppliers publish.
The basic operating principle of an audio amplifier is quite simple. An audio amplifier is going to take a low-level music signal. This signal generally comes from a source with a comparatively high impedance. It then converts this signal into a large-level signal. This large-level signal can also drive loudspeakers with low impedance. In order to do that, an amplifier uses one or more elements which are controlled by the low-power signal in order to create a large-power signal. Those elements range from tubes, bipolar transistors to FET transistors.
Tube amplifiers used to be widespread several decades ago. A tube is able to control the current flow according to a control voltage that is connected to the tube. Tubes, however, are nonlinear in their behavior and are going to introduce a fairly large amount of higher harmonics or distortion. A lot of people favor tube amps since these higher harmonics are frequently perceived as the tube amplifier sounding "warm" or "pleasant".
The first generation versions of solid state amps are called "Class-A" amps. Solid-state amps use a semiconductor rather than a tube to amplify the signal. Usually bipolar transistors or FETs are being used. In class-A amps a transistor controls the current flow according to a small-level signal. A number of amps employ a feedback mechanism to minimize the harmonic distortion. Regarding harmonic distortion, class-A amps rank highest among all types of audio amps. These amplifiers also typically exhibit very low noise. As such class-A amplifiers are perfect for extremely demanding applications in which low distortion and low noise are vital. Though, similar to tube amps, class-A amps have quite small power efficiency and the majority of the power is wasted.
Class-AB amps improve on the efficiency of class-A amps. They utilize a number of transistors to break up the large-level signals into 2 distinct areas, each of which can be amplified more efficiently. Because of the higher efficiency, class-AB amps do not require the same amount of heat sinks as class-A amps. As a result they can be manufactured lighter and less costly. Class-AB amps have a downside though. Each time the amplified signal transitions from a region to the other, there will be certain distortion generated. In other words the transition between those two areas is non-linear in nature. Therefore class-AB amps lack audio fidelity compared with class-A amplifiers.
To improve on the low efficiency of class-A amps, class-AB amplifiers utilize a series of transistors which each amplify a separate area, each of which being more efficient than class-A amplifiers. As such, class-AB amplifiers are usually smaller than class-A amplifiers. Class-AB amps have a downside however. Each time the amplified signal transitions from a region to the other, there will be some distortion created. In other words the transition between these 2 areas is non-linear in nature. As a result class-AB amps lack audio fidelity compared with class-A amplifiers.
New amplifiers incorporate internal audio feedback in order to minimize the amount of music distortion. One kind of audio amps which utilizes this kind of feedback is known as "class-T" or "t amp". Class-T amps feed back the high-level switching signal to the audio signal processor for comparison. These amps have low audio distortion and can be made very small.
The basic operating principle of an audio amplifier is quite simple. An audio amplifier is going to take a low-level music signal. This signal generally comes from a source with a comparatively high impedance. It then converts this signal into a large-level signal. This large-level signal can also drive loudspeakers with low impedance. In order to do that, an amplifier uses one or more elements which are controlled by the low-power signal in order to create a large-power signal. Those elements range from tubes, bipolar transistors to FET transistors.
Tube amplifiers used to be widespread several decades ago. A tube is able to control the current flow according to a control voltage that is connected to the tube. Tubes, however, are nonlinear in their behavior and are going to introduce a fairly large amount of higher harmonics or distortion. A lot of people favor tube amps since these higher harmonics are frequently perceived as the tube amplifier sounding "warm" or "pleasant".
The first generation versions of solid state amps are called "Class-A" amps. Solid-state amps use a semiconductor rather than a tube to amplify the signal. Usually bipolar transistors or FETs are being used. In class-A amps a transistor controls the current flow according to a small-level signal. A number of amps employ a feedback mechanism to minimize the harmonic distortion. Regarding harmonic distortion, class-A amps rank highest among all types of audio amps. These amplifiers also typically exhibit very low noise. As such class-A amplifiers are perfect for extremely demanding applications in which low distortion and low noise are vital. Though, similar to tube amps, class-A amps have quite small power efficiency and the majority of the power is wasted.
Class-AB amps improve on the efficiency of class-A amps. They utilize a number of transistors to break up the large-level signals into 2 distinct areas, each of which can be amplified more efficiently. Because of the higher efficiency, class-AB amps do not require the same amount of heat sinks as class-A amps. As a result they can be manufactured lighter and less costly. Class-AB amps have a downside though. Each time the amplified signal transitions from a region to the other, there will be certain distortion generated. In other words the transition between those two areas is non-linear in nature. Therefore class-AB amps lack audio fidelity compared with class-A amplifiers.
To improve on the low efficiency of class-A amps, class-AB amplifiers utilize a series of transistors which each amplify a separate area, each of which being more efficient than class-A amplifiers. As such, class-AB amplifiers are usually smaller than class-A amplifiers. Class-AB amps have a downside however. Each time the amplified signal transitions from a region to the other, there will be some distortion created. In other words the transition between these 2 areas is non-linear in nature. As a result class-AB amps lack audio fidelity compared with class-A amplifiers.
New amplifiers incorporate internal audio feedback in order to minimize the amount of music distortion. One kind of audio amps which utilizes this kind of feedback is known as "class-T" or "t amp". Class-T amps feed back the high-level switching signal to the audio signal processor for comparison. These amps have low audio distortion and can be made very small.
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