Music amps are at the very heart of every home theater system. As the quality and output power requirements of modern speakers increase, so do the requirements of stereo amplifiers. With the ever increasing amount of models and design topologies, like "tube amps", "class-A", "class-D" along with "t amplifier" types, it is getting more and more complex to select the amp which is perfect for a particular application. This article is going to describe a few of the most popular terms and clarify a few of the technical jargon which amplifier suppliers frequently use.
An audio amplifier will convert a low-level audio signal which often originates from a high-impedance source into a high-level signal which may drive a speaker with a low impedance. To do that, an amp uses one or more elements that are controlled by the low-power signal in order to produce a large-power signal. These elements range from tubes, bipolar transistors to FET transistors.
Tube amplifiers were frequently used several decades ago and employ a vacuum tube which controls a high-voltage signal in accordance to a low-voltage control signal. Tubes, on the other hand, are nonlinear in their behavior and will introduce a quite large amount of higher harmonics or distortion. A lot of people favor tube amplifiers because those higher harmonics are frequently perceived as the tube amp sounding "warm" or "pleasant".
Solid state amps replace the tube with semiconductor elements, typically bipolar transistors or FETs. The earliest type of solid-state amps is called class-A amplifiers. In a class-A amplifier, the signal is being amplified by a transistor which is controlled by the low-level audio signal. If you need an ultra-low distortion amplifier then you may want to explore class-A amplifiers since they offer amongst the lowest distortion of any audio amplifiers. The major drawback is that just like tube amplifiers class A amps have quite low efficiency. As a result these amps require large heat sinks to radiate the wasted energy and are typically quite bulky.
To improve on the low efficiency of class-A amplifiers, class-AB amps make use of a number of transistors which each amplify a distinct area, each of which being more efficient than class-A amps. Due to the larger efficiency, class-AB amps do not require the same number of heat sinks as class-A amps. For that reason they can be made lighter and cheaper. Class-AB amplifiers have a disadvantage though. Every time the amplified signal transitions from a region to the other, there will be some distortion produced. In other words the transition between these 2 regions is non-linear in nature. As a result class-AB amplifiers lack audio fidelity compared with class-A amps.
By utilizing a number of transistors, class-AB amplifiers improve on the low power efficiency of class-A amplifiers. The working area is split into two separate areas. These 2 areas are handled by separate transistors. Each of those transistors operates more efficiently than the single transistor in a class-A amplifier. The larger efficiency of class-AB amps also has 2 other benefits. Firstly, the necessary number of heat sinking is minimized. For that reason class-AB amps can be made lighter and smaller. For that reason, class-AB amps can be made cheaper than class-A amplifiers. Class-AB amps have a disadvantage though. Every time the amplified signal transitions from a region to the other, there will be certain distortion produced. In other words the transition between those 2 regions is non-linear in nature. Therefore class-AB amps lack audio fidelity compared with class-A amplifiers.
To solve the problem of high music distortion, new switching amplifier designs include feedback. The amplified signal is compared with the original low-level signal and errors are corrected. One kind of audio amplifiers which employs this type of feedback is called "class-T" or "t amplifier". Class-T amplifiers feed back the high-level switching signal to the audio signal processor for comparison. These amplifiers have small audio distortion and can be manufactured extremely small.
An audio amplifier will convert a low-level audio signal which often originates from a high-impedance source into a high-level signal which may drive a speaker with a low impedance. To do that, an amp uses one or more elements that are controlled by the low-power signal in order to produce a large-power signal. These elements range from tubes, bipolar transistors to FET transistors.
Tube amplifiers were frequently used several decades ago and employ a vacuum tube which controls a high-voltage signal in accordance to a low-voltage control signal. Tubes, on the other hand, are nonlinear in their behavior and will introduce a quite large amount of higher harmonics or distortion. A lot of people favor tube amplifiers because those higher harmonics are frequently perceived as the tube amp sounding "warm" or "pleasant".
Solid state amps replace the tube with semiconductor elements, typically bipolar transistors or FETs. The earliest type of solid-state amps is called class-A amplifiers. In a class-A amplifier, the signal is being amplified by a transistor which is controlled by the low-level audio signal. If you need an ultra-low distortion amplifier then you may want to explore class-A amplifiers since they offer amongst the lowest distortion of any audio amplifiers. The major drawback is that just like tube amplifiers class A amps have quite low efficiency. As a result these amps require large heat sinks to radiate the wasted energy and are typically quite bulky.
To improve on the low efficiency of class-A amplifiers, class-AB amps make use of a number of transistors which each amplify a distinct area, each of which being more efficient than class-A amps. Due to the larger efficiency, class-AB amps do not require the same number of heat sinks as class-A amps. For that reason they can be made lighter and cheaper. Class-AB amplifiers have a disadvantage though. Every time the amplified signal transitions from a region to the other, there will be some distortion produced. In other words the transition between these 2 regions is non-linear in nature. As a result class-AB amplifiers lack audio fidelity compared with class-A amps.
By utilizing a number of transistors, class-AB amplifiers improve on the low power efficiency of class-A amplifiers. The working area is split into two separate areas. These 2 areas are handled by separate transistors. Each of those transistors operates more efficiently than the single transistor in a class-A amplifier. The larger efficiency of class-AB amps also has 2 other benefits. Firstly, the necessary number of heat sinking is minimized. For that reason class-AB amps can be made lighter and smaller. For that reason, class-AB amps can be made cheaper than class-A amplifiers. Class-AB amps have a disadvantage though. Every time the amplified signal transitions from a region to the other, there will be certain distortion produced. In other words the transition between those 2 regions is non-linear in nature. Therefore class-AB amps lack audio fidelity compared with class-A amplifiers.
To solve the problem of high music distortion, new switching amplifier designs include feedback. The amplified signal is compared with the original low-level signal and errors are corrected. One kind of audio amplifiers which employs this type of feedback is called "class-T" or "t amplifier". Class-T amplifiers feed back the high-level switching signal to the audio signal processor for comparison. These amplifiers have small audio distortion and can be manufactured extremely small.
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