Pro Audio Amplifiers

An amplifier receives an audio signal from an instrument, mixeror signal processor and increases it to a power that can be converted into sound via speakers.

Types of Pro Audio amplifier

  • Instrument amplifier - such as a guitar or bass guitar amplifier. 
  • Mixer amplifier - an audio mixer that is ‘powered’ meaning that it contains a built in amplifier
  • Power amplifier - boosts low powered electronic audio signals to a level that they can drive a speaker to create sound

Operating classes of audio amplifiers

  • Class A  -have the lowest levels of distortion and the best sound, but use a lot of energy and generate heat up whilst in use. 
  • Class B - are more power efficient that Class A, but do create some distortion. 
  • Class AB - use two signals to provide efficiency of a Class B and the sound quality of a Class A.
  • Class D - are digital have a very high level of efficiency, generate far less heat than a Class A and can be manufactured to be very small, allowing them to be integrated into active speakers, headphones and more.

Technology types

  • Solid state - use software or transistors, and are often cheaper, lighter options that require the least maintenance. 
  • Tube / vacuum tube / valve - the preference of performers who crave the ‘analogue’ sound consisting of richer tones and a warmer sound, these amps are heavier, more expensive and require maintenance when valves wear out.
  • Hybrid - uses a solid state power amp alongside a valve preamp. It gives the warmer sound whilst keeping the amp cheaper and lighter than a  valve amplifier. 

Matching speakers to amplifiers

If an amplifier does not compliment speakers it is used with, either sound quality will degrade or the speakers may become damaged.

  • Power ratings - an amplifier should deliver twice the amount of power as the power rating on a speaker, per speaker. If an amp is going to be used with two speakers then the power delivery needs to be per channel.
  • Impedance - stated in ohms, the impedance on the amp should match that of the speakers. This is an important value in determining you do not blow your speaker and will depend on your system setup. Research impedance further if you are unsure.