The stereo power amplifier can easily handle volume peaks and speaker efficiency. The power amplifier is seen as the one that produces loud sounds. The power amplifiers take the incoming electrical signal and magnify it to a level where it drives a loudspeaker. These are classified based on following several classes.
Class A amplifiers: These can be operated at full power and used for low distortion and detailed music reproduction
Class B amplifiers: These can be operated only in the presence of incoming signal and are more energy efficient than Class A amps. The output power of Class B amplifier is usually switched off and on, these amps are subject to higher levels of distortion than Class A.
Class A/B amplifiers: This is the third category and is called transistor or the solid-state amplifiers and combine best characteristics of Class A and B amplifiers.
Class D amplifiers: The switching, power amplifiers are fully on or off. Such type of amplifiers process the incoming analog signals into digital form, which consists of high-frequency pulse wide modulations (PWM). These can theoretically operate at 100 percent efficiency and use far less power than the traditional linear amplifiers.
Out of these classes the majority of amplifiers at present are based on technology called Class-D which can offer higher power efficiency than Class-A or Class-AB technology based amplifiers.
Whenever one plans to buy a power amplifier, it is advisable to seek proper professional help from sound technicians. The most important point to be kept in mind is to know whether the loudspeakers are compatible to amplifiers. The power input should be in control otherwise it might create too much of complications in the music systems.
When choosing a power amplifier, its output wattage should be properly checked in. The other important factor is the total harmonic distortion or THD. There is no such amplifier which is can give ideal amplified signal because there are error components which distort the signal to certain degree.
The other parameter to be looked upon is the signal-to-noise ratio. It signifies the amount of hum and noise the amplifier can add upto the audio signal.