Choosing a superior audio amplifier for your loudspeakers is not a trivial job. You want to make sure that your amplifier matches your loudspeakers. I will describe some fundamental amplifier language and give some pointers to aid you select the perfect amplifier.

There is a variety of different audio amps available which all differ in their specifications, shape and size. This makes it difficult to make a decision which model to pick. You don’t have to be a guru. Just follow some simple rules and you ought to be pleased with your amplifier.

The most apparent criterion is the size of the amp. There are types that are as large as half your living room while several of the newest mini amplifier types are as tiny as a bar of soap. A big number of amplifiers are the size of a typical rack. This allows your amplifier to be stacked on top of your other audio equipment.

The huge majority of today’s audio amps are solid state amplifiers versus more conventional tube amplifiers. Tube amplifiers have been prevalent a decade or so ago. Unfortunately, tube amplifiers have relatively high audio distortion which describes how much the audio signal is degraded by the amp.

An audio distortion of up to 10% is typical for tube amps whereas solid-state amps have lower audio distortion depending on the specific technology. In the past, typically “Class-A” and “Class-AB” amps were obtainable which are also known as “analog amplifiers”. This technology provides rather small audio distortion. On the other hand, the power efficiency is only 10 to 30%. Power efficiency refers to how much of the electrical power is really utilized to amplify the signal. The left over portion is wasted as heat. An amp with low power efficiency will radiate the majority of its power as heat.

In contrast, “Class-D” amps which are also known as “digital amplifiers” have a power efficiency of usually 80 to 90%. This allows the amplifier and power supply to be made much smaller than analog amplifiers. The disadvantage is that digital amps frequently have higher audio distortion than analog amplifiers. This is for the most part a result of the switching distortion of the output power stage. Latest digital audio amplifiers, though, employ a feedback mechanism and can reduce the audio distortion to below 0.05%.

Your amplifier should deliver enough power to drive your speakers. The amount of power will depend on the power handling rating of your loudspeakers. One more factor is the size of your space. Speaker power handling is given as peak power which describes the maximum amount of power during short bursts whilst average power refers to how much power the loudspeakers can tolerate constantly.

If you have a fairly small listening area then 20 to 50 Watts of power should be sufficient while your speaker might be rated for 100 Watts or more. Loudspeakers on the other hand differ in their impedance and sensitivity. As a rule of thumb loudspeakers with low impedance offer higher sensitivity. High-sensitivity speakers are less difficult to drive to high volume than low-sensitivity loudspeakers. Check your amplifier manual to make certain that your amplifier can drive your speaker impedance.

Two additional essential parameters to look at when choosing an amp are signal-to-noise ratio and frequency response. Signal-to-noise ratio denotes how much noise the amp will introduce and should be at least 100 dB for a high-quality amp. The frequency response reveals which audio frequency range the amplifier covers and should be no less than 20 Hz to 20 kHz.