There are three stages power supply stage

It is named solely on the power it outputs. It sends an "amplified" signal to the loudspeakers to give it the bass sound. An amplifiers main purpose is to take a weak signal and make it strong enough to drive the loudspeaker.Cell Phone Antenna Booster
With a subwoofer speaker system, the power amplifier works on and input and output basis. There are three stages power supply stage, input stage, and output stage. When learning about or dealing with these stages you will come to see a lot of technical jargon that can be hard for some to understand.
The power supply stage deals with powering the Cell Phone Antenna Booster . This happens by taking 120 Volts Alternating Currents (VAC) and converting it to Direct Currents (DC). An easy way to understand this is that your amplifier will convert the power coming in so that it is usable.
The amplifier, on the other hand, is the one responsible for amplifying the strength of the signal to significant levels, once the signal is processed and sent from the preamplifier to the amplifier. The amplifier is actually the one that will give your awesome speakers a hell of a workout. It has the capability to drive your speakers to its maximum potential.
The basic parts of an integrated amplifier are actually quite similar to receivers. Receivers are a combination of three basic components which includes an amplifier, a control center, and an AM/FM tuner.The integrated amplifier, on the other hand, integrates a multi-channel amplifier and a preamplifier, otherwise known as a control amplifier, which is previously discussed. Integrated amplifiers usually do not have AM/FM tuners, as they are typically accompanied by a separate AM/FM tuner.
Audio integrated amps are quite rare when it comes to stereo systems. To a lot of consumers, stereo receivers, which consist of a radio tuner and sometimes a satellite radio, are more popular. However, many enthusiasts typically use separate preamplifiers and amplifiers, and separate tuners as well, if they wish to listen to the radio on their system.
Some people on the other side of the aisle do prefer integrated amplifiers over the separate ones for various reasons such as eliminating the clutter of excess connections, which can result in distortions, save some needed space, as well as cut costs on separate devices that may cause a mismatch in circuitry and design.