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Gear Tech




 The Power Amplifier

  The amplifier converts the relatively weak electrical impulses received from the source into power sufficient to drive the speakers. The amount of power that an amplifier can produce is rated in watts. Depending on the requirements of the speaker system, an amplifier may deliver from 1 watt to 3 kilowatts of electrical power. The amplifier is controlled, as a rule, by a device called the preamplifier, which amplifies minute sound- signal voltages too small for the amplifier to handle.

  Preamplifiers may also contain an EQ section of some type to help compensate for different types of rooms, speakers, or sources.

  The power amplifier consists of three sections:

  1. the driver stage

  2. the output section

  3. the power supply

 The Driver Stage

  The driver stage is a voltage gain stage, which is much the same as a pre-amp for your turntable stylus, and usually has about 25 to 30 dB of gain or output. Its main purpose is to provide the amplifier with the signal required to effectively operate the power amp.

 The Output Section

  The output section uses the 30 dB or more of gain and supplies a good deal of power to the speakers. The output section will amplify the signal to provide the volume that you require.

  In addition to providing power, the output stage must also isolate the amp from the very low impedance of the speaker.

 The Power Supply

  The power supply plays a large role in an amplifier, as it provides an even supply of AC power to the output section. If the supply of power is not even, your amplifier will not run smoothly. Just as the car with 2 or 3 spark plugs missing, you will find the power will fluctuate. Without proper power, the amplifier will not put out full output in which the amplifier is capable of.


  Clipping refers to the power level at which an amplifier begins to distort a waveform by flattening its top and bottom into a square wave-shape. When fed to tweeters and or midrange speakers, this may result in exceeding their maximum power handling capacity, causing damage to the speaker voice coil. Clipping can be identified by a fuzzy or distorted sound. If this is heard, lower the volume immediately to avoid damage to your system. Another way to know if you are clipping is by the amplifier: the clipping lights will flash when you that you are going beyond the limit of the amplifier.

Continuous clipping will damage or burn out the speaker

  When any piece of equipment is clipping, other major problems can occur. Such as over-excursion of the speaker,(the amplifier sending DC current to the speakers,) which will eventually burn up the coil of the speaker and cause arcing of the coil. When the coil shorts out, it is possible for the amplifier to either shut down, short out, or blow a fuse. Either way, it's not a good thing to happen in the middle of a dance.


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