Science/Electronics of Amplifiers (1 Viewer)

[Michael-N]

I am looking for a more in-depth view of the internals of an amplification system. More specifically the internals and the specific functions of a pre-amplifier as well as the power amplifier from an electronics standpoint. What components are involved to do the amplification, the differences of how/what the pre and power amps amplify, etc. If anyone knows of any websites that detail perhaps specific models and how they function, or if anyone could recommend a few good books on the topic, I would appreciate it.

 

[Michael R Price]

In short: Your audio signals are represented by electric voltages that are originally produced in a signal source (CD player, digital decoder, etc) at relatively low strength. The pre-amplifier is used to select between multiple sources and adjust the signal strength (increase the voltage) to the appropriate level for a power amplifier, which usually has a constant gain. The power amplifier further increases the signal voltage, but more importantly it provides as much current as is needed by the speaker to turn that signal into sound. Signal amplification is accomplished in individual stages built from tubes or transistors that alter the signal in a certain way and pass it on to the next stage. All amplification circuits are built from the same basic building blocks but as you move up the line to the power amplifier output stage, these components are larger and more powerful.

A typical power amplifier may have an input stage to buffer the input signal source from the rest of the amplifier, a voltage amplication stage to increase the voltage of the signal to the final level, and an output stage that keeps the voltages from the driver stage, but delivers the additional current to drive the speaker.

A few good sites on amplifiers:
http://sound.westhost.com/articles.htm
http://www.passdiy.com
http://www.dself.dsl.pipex.com/ampins/ampdept.htm