Wednesday, February 26, 2014

Discovering The Truth About The Latest Stereo Amps

By Marta McBrian


When selecting a new amplifier, you almost certainly will take a look at the technical specifications. An often found specification is the frequency response. This specification even though crucial does not tell the full story pertaining to how great the amplifier is going to sound. To help you make a smarter buying decision, I am going to make clear what this specification means and the way to understand it. This ideally will make certain you're going to get the best amp for your task. An amplifier is able to only operate within the specific frequency range. Any signals just outside of this range are going to be removed. Consequently the frequency response offers an important hint pertaining to whether a certain amplifier might be suitable for a specific use. Usually a lower and upper frequency are provided, for instance 20 Hz - 20 kHz. This kind of specification suggests that the amplifier has the ability to amplify music inside of that frequency range. It may seem the larger the frequency response the higher quality the amplifier. That, however, will not necessarily be. You need to evaluate the specifications far more closely to be able to properly understand all of them.

A large frequency response doesn't mean the amp provides great audio quality. As an example an amp having a frequency response between 30 Hz and 15 kHz might sound a lot better than another amp having a response between 10 Hz and 30 kHz. In addition, every manufacturer, it seems, utilizes a different way of specifying the lowest and maximum frequency of their amps. Ordinarily, the frequency response shows the normal working range of the amplifier. Inside this range, the amplifier gain is largely constant. At the upper and lower cutoff frequencies the gain will decrease by no more than 3 decibels.

Then again, some companies push this standard to the limit and tend to list a maximum frequency where the amplifier is going to barely generate a signal any more. In addition, simply looking at these 2 figures will not say much concerning the linearity of the frequency response. If possible you should make an effort to obtain a frequency response diagram from the producer. In this chart, you will see how the amplifier functions within the frequency response range. You may also spot any peaks along with valleys the amplifier could possibly have. You may additionally want to demand a phase response diagram that also gives essential hints regarding the sound quality. The circumstances under which the frequency response was measured are also crucial to comprehend. In fact amps could have different frequency responses depending on the speaker that is connected.

This change is most apparent with many digital amplifiers, referred to as Class-D amplifiers. Class-D amplifiers have a lowpass filter inside their output to reduce the switching components that are generated from the internal power FETs. The lowpass filter characteristic, on the other hand, greatly depends upon the attached load.

Various amplifier topologies offer a way to compensate for changes in the amplifier gain with different speaker loads. One of those approaches makes use of feedback. The amplifier output signal after the interior lowpass is input to the amplifier input for comparison. If not created correctly, this technique may cause instability of the amp however. An additional approach is to provide specific outputs for different loudspeaker impedances which are attached to the amplifier power stage by way of audio transformers.




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