Why Is a Class D Amplifier a Good Choice, and What Does It Do?

Why Is a Class D Amplifier a Good Choice, and What Does It Do?

If you believe that Class D amplifier are inferior to Class-A devices by only "two letters," think again: With more power and less weight than ever before, Class-D technology is having a significant impact on the live sound industry. But what are they, and how can they be useful? With the post, let's discover more about class D amplifier.

What is Class D Amplifier

A Class D amplifier is one that produces a switching waveform at a frequency that is significantly higher than the highest audio signal that must be generated. The real needed audio waveform is represented by the average value of this waveform after low-pass filtering.


Class D amplifier operate with extremely high efficiency—often as high as 90%—because the output transistors are either fully turned on or fully off. The inefficiency of other amplifier types is eliminated entirely by doing this, as it makes no use of the transistor's linear area. Achieving fidelity similar to class AB is possible with modern Class D amplifiers.

Functions of Class D Amplifier

A switching amplifier is another name for a class-D amplifier. A class D amplifier uses the idea of pulse width modulation in place of increasing the input signal using linear gain stages.


This changes the input signal into pulses. However, it's a hard subject. Following that, the output stage alternates at a high frequency to represent the pulses that the signal underwent conversion into. After processing, a low-pass filter is used to eliminate the high-frequency nose from the amplified signal and restore its original waveform.

What Is Unique About Class D Amplifier?

Class-D amplifiers require substantially smaller power transformers than class-AB amplifiers because the pulse width modulation allows amplification to occur at far higher frequencies than usual. This implies that a smaller area may accommodate a lot more amplification.

Because of their excellent efficiency, these amplifiers can provide more volume with less power. Class AB amplifiers seldom achieve efficiency levels higher than 60 per cent, whereas class-D amplifiers regularly achieve maximum efficiency values of 90 per cent or more.


Class-D amplifiers aren't flawless, of course. These aren't ideal for audiophile use because of the low-pass filter, which is designed to filter out unwanted noise, which can degrade the high-end. Certain class-D amplifiers may also display distortion, and some individuals—audiophiles especially—just don't like the way these amplifiers sound in general.


Class-D amplifiers are ideal for some applications because of their small size and excellent efficiency despite their drawbacks.


Advantages of class D amplifier

Class-D amplifier provides the essential benefits of low cost and high efficiency, making it possible to manufacture powerful amplifiers at a reasonable price.

The popularity of class-D amplifiers in the value segment of the market can be partially attributed to their desirable qualities of high power and cheap cost. When compared to class-AB amplifiers, class-D amplifiers offer significantly higher efficiency and, hence, more Watts per $. Additionally, it lowers build costs by streamlining production and enabling the use of much smaller parts.

Class-D refers to high value, low cost, and high power. So, Class-D amplifiers are ideal for home theatre amplifiers and subwoofers, where low cost and high power density are critical factors. Who wouldn't want a 1000W compact subwoofer at a reasonable price? True high-end gear only needs to sound the best; it doesn't need to be compact, light, economical, or efficient. 



Class-D amplifier was all the rage in the eighties, but a lot of the designs proved to be unreliable because they used SMD components, were made with inexpensive, off-the-shelf modules, and were manufactured and assembled at low cost. Nonetheless, Class-D is still relevant, primarily in the high-value segment of the market.

Choose a class D amplifier for your home stereo system

The resistance of the speaker is a crucial factor to take into account when choosing an amplifier because these devices have limitations on their voltage and current. Drivers usually vary in size from 2 to 8 Ω. As long as the amplifier can handle it, a lower-impedance driver draws more current and generates higher output power.

The majority of amplifiers used in home stereo systems are class D amplifier, so keep that in mind when you hunt for the best audio amplifier for your setup. The home theatre stereo system practically always uses it. Because it is much smaller than other amplifiers, performs steadily, and has an easy-to-understand design. It works best with a Bluetooth surround system or wireless surround sound speaker, which is another reason. If you want to avoid hearing pops, clicks, or hisses from your audio system, then going with a class D power amp is the best option for you. 


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