Music amplifiers are at the very heart of every home theater system. As the quality and output power demands of today's speakers increase, so do the requirements of stereo amplifiers. There is a big quantity of amplifier styles and types. All of these vary regarding performance. I am going to describe some of the most popular amplifier terms like "class-A", "class-D" and "t amps" to help you figure out which of these amps is ideal for your application. Moreover, after understanding this guide you should be able to comprehend the amp specifications which makers issue.
Simply put, the purpose of an audio amplifier is to convert a low-power music signal into a high-power music signal. The high-power signal is great enough to drive a speaker adequately loud. Determined by the type of amp, one of several kinds of elements are used in order to amplify the signal including tubes in addition to transistors.
A couple of decades ago, the most widespread kind of audio amplifier were tube amps. Tube amplifiers employ a tube as the amplifying element. The current flow through the tube is controlled by a low-level control signal. In that way the low-level audio is converted into a high-level signal. One problem with tubes is that they are not very linear when amplifying signals. Aside from the original music, there are going to be overtones or higher harmonics present in the amplified signal. Thus tube amplifiers have moderately large distortion. Many people prefer tube amplifiers because these higher harmonics are often perceived as the tube amp sounding "warm" or "pleasant".
Solid state amplifiers replace the tube with semiconductor elements, usually bipolar transistors or FETs. The earliest kind of solid-state amplifiers is generally known as class-A amplifiers. In a class-A amp, 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 might want to explore class-A amplifiers since they offer amongst the smallest distortion of any audio amps. Though, similar to tube amps, class-A amplifiers have quite small power efficiency and most of the power is wasted.
Solid state amplifiers replace the tube with semiconductor elements, usually bipolar transistors or FETs. The earliest kind of solid-state amps is known as class-A amplifiers. The working principle of class-A amps is very similar to that of tube amplifiers. The major difference is that a transistor is being utilized instead of the tube for amplifying the audio signal. The amplified high-level signal is at times fed back to reduce harmonic distortion. If you require an ultra-low distortion amplifier then you might want to investigate class-A amplifiers since they provide amongst the smallest distortion of any audio amps. The main drawback is that just like tube amplifiers class A amps have quite small efficiency. As a result these amplifiers need large heat sinks to radiate the wasted energy and are usually quite large.
Class-D amplifiers improve on the efficiency of class-AB amplifiers even further by employing a switching transistor that is continuously being switched on or off. Thus this switching stage hardly dissipates any power and as a result the power efficiency of class-D amps frequently surpasses 90%. The on-off switching times of the transistor are being controlled by a pulse-with modulator (PWM). Standard switching frequencies are in the range of 300 kHz and 1 MHz. This high-frequency switching signal has to be removed from the amplified signal by a lowpass filter. Commonly a simple first-order lowpass is being used. Both the pulse-width modulator and the transistor have non-linearities that result in class-D amps having larger audio distortion than other types of amps.
To resolve the problem of large audio distortion, newer switching amp styles incorporate feedback. The amplified signal is compared with the original low-level signal and errors are corrected. One kind of audio amplifiers which uses 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 amplifiers have small audio distortion and can be manufactured very small.
Simply put, the purpose of an audio amplifier is to convert a low-power music signal into a high-power music signal. The high-power signal is great enough to drive a speaker adequately loud. Determined by the type of amp, one of several kinds of elements are used in order to amplify the signal including tubes in addition to transistors.
A couple of decades ago, the most widespread kind of audio amplifier were tube amps. Tube amplifiers employ a tube as the amplifying element. The current flow through the tube is controlled by a low-level control signal. In that way the low-level audio is converted into a high-level signal. One problem with tubes is that they are not very linear when amplifying signals. Aside from the original music, there are going to be overtones or higher harmonics present in the amplified signal. Thus tube amplifiers have moderately large distortion. Many people prefer tube amplifiers because these higher harmonics are often perceived as the tube amp sounding "warm" or "pleasant".
Solid state amplifiers replace the tube with semiconductor elements, usually bipolar transistors or FETs. The earliest kind of solid-state amplifiers is generally known as class-A amplifiers. In a class-A amp, 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 might want to explore class-A amplifiers since they offer amongst the smallest distortion of any audio amps. Though, similar to tube amps, class-A amplifiers have quite small power efficiency and most of the power is wasted.
Solid state amplifiers replace the tube with semiconductor elements, usually bipolar transistors or FETs. The earliest kind of solid-state amps is known as class-A amplifiers. The working principle of class-A amps is very similar to that of tube amplifiers. The major difference is that a transistor is being utilized instead of the tube for amplifying the audio signal. The amplified high-level signal is at times fed back to reduce harmonic distortion. If you require an ultra-low distortion amplifier then you might want to investigate class-A amplifiers since they provide amongst the smallest distortion of any audio amps. The main drawback is that just like tube amplifiers class A amps have quite small efficiency. As a result these amplifiers need large heat sinks to radiate the wasted energy and are usually quite large.
Class-D amplifiers improve on the efficiency of class-AB amplifiers even further by employing a switching transistor that is continuously being switched on or off. Thus this switching stage hardly dissipates any power and as a result the power efficiency of class-D amps frequently surpasses 90%. The on-off switching times of the transistor are being controlled by a pulse-with modulator (PWM). Standard switching frequencies are in the range of 300 kHz and 1 MHz. This high-frequency switching signal has to be removed from the amplified signal by a lowpass filter. Commonly a simple first-order lowpass is being used. Both the pulse-width modulator and the transistor have non-linearities that result in class-D amps having larger audio distortion than other types of amps.
To resolve the problem of large audio distortion, newer switching amp styles incorporate feedback. The amplified signal is compared with the original low-level signal and errors are corrected. One kind of audio amplifiers which uses 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 amplifiers have small audio distortion and can be manufactured very small.
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