Power Amplifier

Power amplifiers, or weak-signal amplifiers, are used for wireless receivers, broadcast transmitters, acoustic pickups, hi-fi audio speakers, compact disc players and more. They are designed to amplify particularly small input signals. Top power amplifiers are able to produce much larger levels of voltage than the original signal, with minimal internal noise.

Things to Consider Before You Buy
It's important that your power amp converts signal with a minimum of wattage loss. This is known as the efficiency rate of conversion. For each source, the efficiency rate of power amplifiers varies. For example, for hi-fi audio amps, efficiency ranges from about 50 to 70 percent. For typical audio applications, on the other hand, efficiency generally falls between 30 and 50 percent. When you convert signal from a very small source to a large source, the end result may not be quite what you expected.

With hi-fi audio systems, distortion, or clipping, is an important factor to keep in mind as well. Clipping is the extent to which the original source audio is changed in the conversion process. The lower the rate of clipping, the better the quality of sound. More distortion will typically mean poorer sound and less fidelity.

Power amps are rated in watts or ohms. Typically, the most common power ratings range from two to eight ohms. Features vary among manufacturers, but some include power meters, clipping indicators (to measure the amount of distortion), and thermal overload shutdown. The more you can determine the efficiency, clipping amount, and other measurements, the more useful your power amp will be.