- 1). Decide which method of amplification you are going to use. If you are making a musical instrument power amplifier, such as a guitar amp, you can choose between the tube or transistor powered method. Vacuum tubes use heat to control the movement of electrons. They add warmth to a guitar amp's sound but they require ongoing maintenance. Transistors use a semi-conductor to amplify the signal.
- 2
This Fender guitar amp has an integrated power amplifier.amplifier image by Darko Draskovic from Fotolia.com
Plan out how the power amp functions with the preamp section. Your power amp will either be stand-alone or it will form part of an amplifier chassis. Guitar amplifiers rarely have stand-alone power amplifiers, for convenience reasons. In home stereo systems, stand-alone amps are more common. The configuration of your power amplifier is influenced by its relationship to the preamp. For example, If you are building a guitar amp with an integrated power and preamp section, the power handling of each must be equal. Home stereo stand-alone power amplifiers typically have variable power handling to accommodate a range of input levels. - 3). Design your output stage. Decide between class A, class AB and class B type amplification. This will have a large influence on the rest of your power amplification configuration. Class A is single-ended, it's the simplest configuration but is least efficient. The output signal is a scaled replica of the input signal. Class AB and class B are double-ended configurations. This means that waveform is split and there is no plate current when the input signal is zero. This is a more efficient means of amplification.
- 4). Design your input stage circuitry. The input stage is where the signal from the stereo or instrument is converted to an output signal. Consult schematics for various other amplifiers to see how they differ. The long-tailed pair is the most common input stage circuitry configuration. This configuration takes a low input signal and converts it into a high impedance signal. The single-transistor configuration is less common. It is simpler and more stable than the long-tailed pair but has fewer power handling capabilities.
SHARE
