Requirements concerning audio power and audio fidelity of latest loudspeakers and home theater products are always increasing. At the center of those systems is the audio amp. Modern stereo amps have to perform well enough to satisfy these ever increasing requirements. There is a huge amount of amp styles and models. All of these differ in terms of performance. I am going to describe a few of the most widespread amplifier terms including "class-A", "class-D" and "t amps" to help you figure out which of these amps is best for your application. Moreover, after understanding this essay you should be able to understand the amplifier specs which manufacturers show.
Simply put, the purpose of an audio amp is to translate a low-power music signal into a high-power music signal. The high-power signal is great enough to drive a loudspeaker sufficiently loud. The type of element used to amplify the signal depends on which amp architecture is used. A few amps even utilize several types of elements. Normally the following parts are utilized: tubes, bipolar transistors in addition to FETs.
Tube amps used to be popular a couple of decades ago. A tube is able to control the current flow according to a control voltage that is attached to the tube. Regrettably, tube amplifiers have a somewhat high level of distortion. Technically speaking, tube amplifiers are going to introduce higher harmonics into the signal. On the other hand, this characteristic of tube amps still makes these popular. A lot of people describe tube amplifiers as having a warm sound as opposed to the cold sound of solid state amplifiers.
Solid-state amps utilize a semiconductor element, such as a bipolar transistor or FET in place of the tube and the first sort is called "class-A" amps. The working principle of class-A amplifiers is very similar to that of tube amplifiers. The key difference is that a transistor is being used rather than the tube for amplifying the music signal. The amplified high-level signal is at times fed back to reduce harmonic distortion. In terms of harmonic distortion, class-A amps rank highest among all types of power amps. These amps also typically exhibit very low noise. As such class-A amplifiers are ideal for very demanding applications in which low distortion and low noise are essential. The major downside is that similar to tube amps class A amplifiers have very small efficiency. As a result these amplifiers require big heat sinks to dissipate the wasted energy and are usually quite heavy.
The first generation versions of solid state amplifiers are referred to as "Class-A" amps. Solid-state amplifiers make use of a semiconductor rather than a tube to amplify the signal. Typically bipolar transistors or FETs are being utilized. In a class-A amp, the signal is being amplified by a transistor which is controlled by the low-level audio signal. Class-A amps have the smallest distortion and usually also the lowest amount of noise of any amplifier architecture. If you need ultra-low distortion then you should take a closer look at class-A types. Class-A amps, on the other hand, waste the majority of the energy as heat. As a result they typically have big heat sinks and are quite bulky.
Class-D amplifiers are able to achieve power efficiencies higher than 90% by making use of a switching transistor which is continuously being switched on and off and therefore the transistor itself does not dissipate any heat. The switching transistor, that is being controlled by a pulse-width modulator generates a high-frequency switching component that needs to be removed from the amplified signal by using a lowpass filter. The switching transistor and also the pulse-width modulator generally exhibit quite large non-linearities. As a consequence, the amplified signal is going to contain some distortion. Class-D amplifiers by nature have larger audio distortion than other types of audio amplifiers.
Newer amplifiers incorporate internal audio feedback to reduce the amount of audio distortion. "Class-T" amps (also called "t-amp") employ this kind of feedback method and for that reason can be made extremely small while achieving small audio distortion.
Simply put, the purpose of an audio amp is to translate a low-power music signal into a high-power music signal. The high-power signal is great enough to drive a loudspeaker sufficiently loud. The type of element used to amplify the signal depends on which amp architecture is used. A few amps even utilize several types of elements. Normally the following parts are utilized: tubes, bipolar transistors in addition to FETs.
Tube amps used to be popular a couple of decades ago. A tube is able to control the current flow according to a control voltage that is attached to the tube. Regrettably, tube amplifiers have a somewhat high level of distortion. Technically speaking, tube amplifiers are going to introduce higher harmonics into the signal. On the other hand, this characteristic of tube amps still makes these popular. A lot of people describe tube amplifiers as having a warm sound as opposed to the cold sound of solid state amplifiers.
Solid-state amps utilize a semiconductor element, such as a bipolar transistor or FET in place of the tube and the first sort is called "class-A" amps. The working principle of class-A amplifiers is very similar to that of tube amplifiers. The key difference is that a transistor is being used rather than the tube for amplifying the music signal. The amplified high-level signal is at times fed back to reduce harmonic distortion. In terms of harmonic distortion, class-A amps rank highest among all types of power amps. These amps also typically exhibit very low noise. As such class-A amplifiers are ideal for very demanding applications in which low distortion and low noise are essential. The major downside is that similar to tube amps class A amplifiers have very small efficiency. As a result these amplifiers require big heat sinks to dissipate the wasted energy and are usually quite heavy.
The first generation versions of solid state amplifiers are referred to as "Class-A" amps. Solid-state amplifiers make use of a semiconductor rather than a tube to amplify the signal. Typically bipolar transistors or FETs are being utilized. In a class-A amp, the signal is being amplified by a transistor which is controlled by the low-level audio signal. Class-A amps have the smallest distortion and usually also the lowest amount of noise of any amplifier architecture. If you need ultra-low distortion then you should take a closer look at class-A types. Class-A amps, on the other hand, waste the majority of the energy as heat. As a result they typically have big heat sinks and are quite bulky.
Class-D amplifiers are able to achieve power efficiencies higher than 90% by making use of a switching transistor which is continuously being switched on and off and therefore the transistor itself does not dissipate any heat. The switching transistor, that is being controlled by a pulse-width modulator generates a high-frequency switching component that needs to be removed from the amplified signal by using a lowpass filter. The switching transistor and also the pulse-width modulator generally exhibit quite large non-linearities. As a consequence, the amplified signal is going to contain some distortion. Class-D amplifiers by nature have larger audio distortion than other types of audio amplifiers.
Newer amplifiers incorporate internal audio feedback to reduce the amount of audio distortion. "Class-T" amps (also called "t-amp") employ this kind of feedback method and for that reason can be made extremely small while achieving small audio distortion.
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