Tips For Spotting The Best Audio Amplifier
Choosing a decent audio amplifier for your loudspeakers is not a trivial task. You wish to make sure that your amp matches your loudspeakers. I will clarify some essential amplifier language and give some suggestions to assist you pick the right amplifier.
It is hard to select the right audio amp due to the large amount of types. All of these models have different specs. They are based on different technologies and are available in all kinds of shapes and sizes. However, you don't have to be a guru to pick the right model. By following some basic rules you won't regret your purchasing decision.
A vital criterion is the size of the amplifier. You can get models which can fill half a room. In contrast, several of the latest miniature amplifier models are no bigger than a deck of cards. A big number of amps are the size of a regular rack. This permits your amplifier to be stacked on top of your other audio devices.
The huge majority of recent audio amps are solid state amplifiers as opposed to more traditional tube amps. Tube amplifiers have been dominant a decade or so ago. Though, tube amps have relatively high audio distortion. Audio distortion refers to how much the audio signal is being degraded whilst passing through the amplifier and is given in percent. This value is often used when comparing the audio quality of amplifiers.
Harmonic distortion of tube amps is often as high as 10%. Solid-state amplifiers will have lower audio distortion. Still, distortion will depend on the specific audio amplifier technology. Several of the most accepted technologies in the past have been "Class-A" and "Class-AB" technologies. These technologies use different arrangements to amplify the audio. Amps based on any of these technologies are also called "analog amplifiers". Audio amplifiers which are based on these technologies normally have low harmonic distortion. In addition, this technology is quite inexpensive. However, the downside is that the power efficiency is merely in the order of 20% to 30%. Power efficiency refers to how much of the electrical power is in fact used to amplify the signal. The remaining part is wasted as heat. An amplifier with low power efficiency will radiate most of its power as heat.
"Class-D" amplifiers, however, which are also named "digital amplifiers" have a power efficiency of no less than 80% and are smaller and have a smaller power supply than similar analog amplifiers. The downside is that many digital amplifiers have larger audio distortion than analog amplifiers though a number of of the latest models employ a feedback mechanism to minimize distortion to levels of 0.05% and below.
When picking an amplifier, make sure that the output power is sufficient to drive your loudspeakers. The needed power will be determined by how much power your loudspeakers can tolerate as well as the size of your space where you will be listening. There are two values for speaker power handling: peak and average power handling. The peak value indicates how much power the loudspeaker can tolerate for short periods of time. The average value on the other hand denotes how much power the loudspeaker can handle continuously without damage.
If you have a relatively small listening environment then 20 to 50 Watts of power should be sufficient even though your speaker might be rated for 100 Watts or higher. Notice though that loudspeakers differ in their sensitivity. Generally a low-impedance speaker will be simpler to drive to high volume than a high-impedance loudspeaker. Check your amplifier manual to make sure that your amplifier can drive your speaker impedance.
Additional key parameters are the signal-to-noise ratio and frequency response which should be in the order of no less than 100 dB signal-to-noise ratio and 20 Hz to 20 kHz frequency response for high-quality amplifiers.