To help you decide on an audio amplifier, I will explain the term "signal-to-noise ratio" which is frequently used to express the performance of audio amplifiers. While searching for an amp, you firstly are going to check the cost, power among additional basic criteria. However, after this initial selection, you will still have several types to choose from. Next you are going to focus more on several of the technical specs, such as signal-to-noise ratio in addition to harmonic distortion. The signal-to-noise ratio is a fairly vital specification and describes how much noise or hiss the amplifier creates.
You can perform a simple comparison of the amp hiss by short circuiting the amp input, setting the volume to maximum and listening to a loudspeaker connected to the amp. Usually you are going to hear two components. The first is hissing. In addition, you will often hear a hum at 50 or 60 Hz. Both of these are components which are created by the amp itself. After that compare different amplifiers according to the next rule: the smaller the level of static, the better the noise performance of the amp. Though, bear in mind that you have to put all amps to amplify by the same amount to evaluate several amps.
You can do a simple assessment of the amp noise by short circuiting the amp input, setting the gain to maximum and listening to a loudspeaker attached to the amplifier. You will hear some amount of hissing and/or hum coming from the loudspeaker. This noise is generated by the amp itself. Be certain that the gain of the amplifiers is set to the same amount. Otherwise you will not be able to objectively compare the amount of noise between different amplifiers. The general rule is: the lower the amount of static which you hear the higher the noise performance. To help you compare the noise performance, amp manufacturers publish the signal-to-noise ratio in their amplifier specification sheets. Simply put, the higher the signal-to-noise ratio, the lower the level of noise the amplifier generates. One of the reasons why amps create noise is the fact that they use elements such as transistors as well as resistors that by nature generate noise. The overall noise is dependent on how much hiss every element produces. However, the position of those components is also essential. Elements which are part of the amplifier input stage are going to normally contribute the majority of the noise.
The majority of recent power amps are digital amps, also known as "class-d amplifiers". Class-D amplifiers use a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. This switching noise may result in some amount of speaker distortion but is generally not included in the the signal-to-noise ratio which only considers noise in the range of 20 Hz and 20 kHz.
Manufacturers measure the signal-to-noise ratio by setting the amp such that the full output swing may be achieved and by feeding a test tone to the amplifier that is generally 60 dB underneath the full scale of the amplifier. Next, only the noise between 20 Hz and 20 kHz is considered. The noise at other frequencies is eliminated through a filter. Next the amount of the noise energy in relation to the full-scale output wattage is computed and shown in decibel.
Often the signal-to-noise ratio is shown in a more subjective manner as "dbA" or "A weighted". In other words, this technique attempts to state how the noise is perceived by a person. Human hearing is most sensitive to signals around 1 kHz while signals below 50 Hz and above 14 kHz are hardly noticed. Therefore an A-weighting filter will magnify the noise floor for frequencies which are easily perceived and suppress the noise floor at frequencies that are hardly heard. Many amps will show a higher A-weighted signal-to-noise ratio than the un-weighted ratio.
You can perform a simple comparison of the amp hiss by short circuiting the amp input, setting the volume to maximum and listening to a loudspeaker connected to the amp. Usually you are going to hear two components. The first is hissing. In addition, you will often hear a hum at 50 or 60 Hz. Both of these are components which are created by the amp itself. After that compare different amplifiers according to the next rule: the smaller the level of static, the better the noise performance of the amp. Though, bear in mind that you have to put all amps to amplify by the same amount to evaluate several amps.
You can do a simple assessment of the amp noise by short circuiting the amp input, setting the gain to maximum and listening to a loudspeaker attached to the amplifier. You will hear some amount of hissing and/or hum coming from the loudspeaker. This noise is generated by the amp itself. Be certain that the gain of the amplifiers is set to the same amount. Otherwise you will not be able to objectively compare the amount of noise between different amplifiers. The general rule is: the lower the amount of static which you hear the higher the noise performance. To help you compare the noise performance, amp manufacturers publish the signal-to-noise ratio in their amplifier specification sheets. Simply put, the higher the signal-to-noise ratio, the lower the level of noise the amplifier generates. One of the reasons why amps create noise is the fact that they use elements such as transistors as well as resistors that by nature generate noise. The overall noise is dependent on how much hiss every element produces. However, the position of those components is also essential. Elements which are part of the amplifier input stage are going to normally contribute the majority of the noise.
The majority of recent power amps are digital amps, also known as "class-d amplifiers". Class-D amplifiers use a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. This switching noise may result in some amount of speaker distortion but is generally not included in the the signal-to-noise ratio which only considers noise in the range of 20 Hz and 20 kHz.
Manufacturers measure the signal-to-noise ratio by setting the amp such that the full output swing may be achieved and by feeding a test tone to the amplifier that is generally 60 dB underneath the full scale of the amplifier. Next, only the noise between 20 Hz and 20 kHz is considered. The noise at other frequencies is eliminated through a filter. Next the amount of the noise energy in relation to the full-scale output wattage is computed and shown in decibel.
Often the signal-to-noise ratio is shown in a more subjective manner as "dbA" or "A weighted". In other words, this technique attempts to state how the noise is perceived by a person. Human hearing is most sensitive to signals around 1 kHz while signals below 50 Hz and above 14 kHz are hardly noticed. Therefore an A-weighting filter will magnify the noise floor for frequencies which are easily perceived and suppress the noise floor at frequencies that are hardly heard. Many amps will show a higher A-weighted signal-to-noise ratio than the un-weighted ratio.
About the Author:
Click for more infos on the subject of mono amps. In addition, go look at http://usa.yamaha.com/products/audio-visual/hifi-components/amps/.
Aucun commentaire:
Enregistrer un commentaire