The following is a comparison of Class A, Class B, Class AB and Class D power amplifiers:
| category | describe | advantage | shortcoming |
|---|---|---|---|
| Class A power amplifier | In a linear amplifier, current flows through the output all the time, but only when an audio signal is present. | - Premium sound quality, low distortion and noise. - Suitable for high-fidelity audio systems and professional audio applications. | - Lower efficiency, higher energy consumption. - It will generate more heat and requires cooling measures. |
| Class B power amplifier | Linear power amplifier, the output terminal only has output when the positive half cycle or negative half cycle of the audio signal exists, no quiescent current is generated, and the power efficiency is high. | - Relatively high efficiency with less energy consumption. - Suitable for lower power audio applications such as general home stereos. | - The output waveform is distorted, and crossover distortion may occur. - High frequency noise may be loud. |
| Class AB power amplifier | Combining the characteristics of Class A and Class B power amplifiers, it achieves a better balance between efficiency and sound quality. | - High efficiency, suitable for applications such as general home audio and car audio. - Relatively low distortion and noise. | - The output waveform is distorted, which may produce crossover distortion, but less than a pure class B amplifier. |
| Class D power amplifier | The digital power amplifier converts the analog audio signal into a digital signal, and controls the output by turning the power on and off through the modulation method, and the power efficiency is very high. | - Extremely high efficiency, consumes less energy and generates less heat. - Ideal for applications requiring high efficiency and small size, such as portable audio equipment and car audio. | - The output waveform is distorted and PWM (Pulse Width Modulation) noise may be generated. - Requires precise filtering and anti-interference design. - Signal processing is complex and may introduce digital noise. - Higher requirements on the input signal may require the use of a low-pass filter. - Requires suppression of power fluctuations and radio frequency interference. - Suitable for small and medium power applications, less high power applications. - May cause interference to radio frequency spectrum. - Not suitable for professional audio applications requiring high fidelity sound quality. |
Please note that each power amplifier type has its applicable scenarios and characteristics, and it is important to choose the power amplifier type that suits your needs. When purchasing a power amplifier, it is recommended to consider various factors based on actual application needs and budget, and choose products with guaranteed brands and quality.