None of modern audio products would be possible without the help of today's stereo amplifiers that try to satisfy higher and higher demands concerning power and music fidelity. With the ever growing amount of models and design topologies, including "tube amplifiers", "class-A", "class-D" as well as "t amplifier" types, it is getting more and more demanding to choose the amplifier which is best for a specific application. This guide will describe a few of the most common terms and spell out a few of the technical jargon which amplifier producers often use.
An audio amplifier will translate a low-level audio signal that often originates from a high-impedance source into a high-level signal which may drive a speaker with a low impedance. The kind of element used to amplify the signal depends on which amplifier architecture is utilized. Several amps even utilize several kinds of elements. Normally the following parts are utilized: tubes, bipolar transistors and FETs.
A number of decades ago, the most widespread type of audio amp were tube amps. Tube amplifiers utilize a tube as the amplifying element. The current flow through the tube is controlled by a low-level control signal. Thereby the low-level audio is transformed into a high-level signal. One drawback with tubes is that they are not very linear when amplifying signals. Aside from the original audio, there are going to be overtones or higher harmonics present in the amplified signal. Consequently tube amps have rather high distortion. Though, this characteristic of tube amps still makes these popular. Many people describe tube amps as having a warm sound versus the cold sound of solid state amplifiers. One disadvantage of tube amps is their low power efficiency. In other words, the majority of the power consumed by the amp is wasted as heat as opposed to being converted into music. As a result tube amps will run hot and need sufficient cooling. Tube amplifiers, though, a quite expensive to manufacture and thus tube amplifiers have mostly been replaced with amplifiers employing transistor elements that are less costly to build.
The first generation models of solid state amplifiers are called "Class-A" amps. Solid-state amplifiers make use of a semiconductor instead of a tube to amplify the signal. Usually bipolar transistors or FETs are being utilized. In class-A amps a transistor controls the current flow according to a small-level signal. Several amps utilize a feedback mechanism to minimize the harmonic distortion. In terms of harmonic distortion, class-A amps rank highest among all kinds of music amps. These amplifiers also regularly exhibit quite low noise. As such class-A amplifiers are ideal for quite demanding applications in which low distortion and low noise are crucial. Yet, similar to tube amps, class-A amps have very small power efficiency and the majority of the energy is wasted.
Solid state amplifiers replace the tube with semiconductor elements, usually bipolar transistors or FETs. The earliest type of solid-state amps is known as class-A amps. In class-A amps a transistor controls the current flow according to a small-level signal. A few amps employ a feedback mechanism to reduce the harmonic distortion. In terms of harmonic distortion, class-A amps rank highest amid all kinds of audio amps. These amps also usually exhibit very low noise. As such class-A amps are perfect for very demanding applications in which low distortion and low noise are important. However, 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 use a number of transistors to break up the large-level signals into 2 separate regions, each of which can be amplified more efficiently. The larger efficiency of class-AB amps also has two further benefits. First of all, the required 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 drawback though. Each time the amplified signal transitions from one region to the other, there will be some distortion created. In other words the transition between those two regions is non-linear in nature. Therefore class-AB amps lack audio fidelity compared with class-A amplifiers.
More modern audio amplifiers incorporate some kind of means in order to minimize distortion. One method is to feed back the amplified music signal to the input of the amp in order to compare with the original signal. The difference signal is then used to correct the switching stage and compensate for the nonlinearity. One kind of audio amplifiers which utilizes this kind of feedback is called "class-T" or "t amp". Class-T amplifiers feed back the high-level switching signal to the audio signal processor for comparison. These amplifiers exhibit low audio distortion and can be made very small.
An audio amplifier will translate a low-level audio signal that often originates from a high-impedance source into a high-level signal which may drive a speaker with a low impedance. The kind of element used to amplify the signal depends on which amplifier architecture is utilized. Several amps even utilize several kinds of elements. Normally the following parts are utilized: tubes, bipolar transistors and FETs.
A number of decades ago, the most widespread type of audio amp were tube amps. Tube amplifiers utilize a tube as the amplifying element. The current flow through the tube is controlled by a low-level control signal. Thereby the low-level audio is transformed into a high-level signal. One drawback with tubes is that they are not very linear when amplifying signals. Aside from the original audio, there are going to be overtones or higher harmonics present in the amplified signal. Consequently tube amps have rather high distortion. Though, this characteristic of tube amps still makes these popular. Many people describe tube amps as having a warm sound versus the cold sound of solid state amplifiers. One disadvantage of tube amps is their low power efficiency. In other words, the majority of the power consumed by the amp is wasted as heat as opposed to being converted into music. As a result tube amps will run hot and need sufficient cooling. Tube amplifiers, though, a quite expensive to manufacture and thus tube amplifiers have mostly been replaced with amplifiers employing transistor elements that are less costly to build.
The first generation models of solid state amplifiers are called "Class-A" amps. Solid-state amplifiers make use of a semiconductor instead of a tube to amplify the signal. Usually bipolar transistors or FETs are being utilized. In class-A amps a transistor controls the current flow according to a small-level signal. Several amps utilize a feedback mechanism to minimize the harmonic distortion. In terms of harmonic distortion, class-A amps rank highest among all kinds of music amps. These amplifiers also regularly exhibit quite low noise. As such class-A amplifiers are ideal for quite demanding applications in which low distortion and low noise are crucial. Yet, similar to tube amps, class-A amps have very small power efficiency and the majority of the energy is wasted.
Solid state amplifiers replace the tube with semiconductor elements, usually bipolar transistors or FETs. The earliest type of solid-state amps is known as class-A amps. In class-A amps a transistor controls the current flow according to a small-level signal. A few amps employ a feedback mechanism to reduce the harmonic distortion. In terms of harmonic distortion, class-A amps rank highest amid all kinds of audio amps. These amps also usually exhibit very low noise. As such class-A amps are perfect for very demanding applications in which low distortion and low noise are important. However, 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 use a number of transistors to break up the large-level signals into 2 separate regions, each of which can be amplified more efficiently. The larger efficiency of class-AB amps also has two further benefits. First of all, the required 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 drawback though. Each time the amplified signal transitions from one region to the other, there will be some distortion created. In other words the transition between those two regions is non-linear in nature. Therefore class-AB amps lack audio fidelity compared with class-A amplifiers.
More modern audio amplifiers incorporate some kind of means in order to minimize distortion. One method is to feed back the amplified music signal to the input of the amp in order to compare with the original signal. The difference signal is then used to correct the switching stage and compensate for the nonlinearity. One kind of audio amplifiers which utilizes this kind of feedback is called "class-T" or "t amp". Class-T amplifiers feed back the high-level switching signal to the audio signal processor for comparison. These amplifiers exhibit low audio distortion and can be made very small.
Post a Comment