Are you looking to acquire a brand new amplifier for your home loudspeakers? You may be dazzled by the amount of choices you have. To make an informed choice, it is best to familiarize yourself with frequent specs. One of these specifications is known as "signal-to-noise ratio" and is not frequently understood. I will help explain the meaning of this term.
After you have narrowed down your search by looking at a few fundamental criteria, such as the level of output wattage, the size of the amp and the cost, you will still have quite a few products to choose from. Now it is time to look at some of the technical specifications in more detail. An important criterion of power amplifiers is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio describes how much hum or hiss the amp is going to add to the audio signal. This ratio is usually shown in decibel or "db" for short.
You can do a simple comparison of the amp hiss by short circuiting the amp input, setting the gain to maximum and listening to a speaker connected to the amplifier. You will hear some amount of hissing and/or hum coming from the loudspeaker. This hiss is created by the amp itself. Then compare different amps according to the next rule: the smaller the level of hiss, the better the noise performance of the amp. Yet, bear in mind that you should put all amps to amplify by the same level in order to compare several amps. When glancing at the amp specification sheet, you want to look for an amp with a high signal-to-noise ratio figure which suggests that the amp outputs a small amount of hiss. One of the reasons why amps create noise is the fact that they use elements such as transistors and resistors that by nature produce noise. The overall noise depends on how much hiss every component produces. Yet, the location of those components is also important. Elements that are part of the amp input stage are going to normally contribute most of the noise.
Many of modern amplifiers are based on a digital switching topology. They are referred to as "class-D" or "class-T" amps. Switching amps include a power stage which is constantly switched at a frequency of approximately 400 kHz. This switching noise may cause some level of loudspeaker distortion yet is typically not included in the the signal-to-noise ratio which merely considers noise between 20 Hz and 20 kHz.
The signal-to-noise ratio is measured by feeding a 1 kHz test signal 60 dB below the full scale and measuring the noise floor of the amp. The amplification of the amp is set such that the full output power of the amp can be realized. Then, the noise floor between 20 Hz and 20 kHz is calculated and the ratio to the full-scale signal computed. The noise signal at different frequencies is eliminated via a bandpass filter throughout this measurement.
One more convention to express the signal-to-noise ratio makes use of more subjective terms. These terms are "dBA" or "A weighted". You are going to discover these terms in a lot of amp parameter sheets. 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 barely heard. An A-weighted signal-to-noise ratio weighs the noise floor in accordance to the human hearing and is normally higher than the unweighted signal-to-noise ratio.
After you have narrowed down your search by looking at a few fundamental criteria, such as the level of output wattage, the size of the amp and the cost, you will still have quite a few products to choose from. Now it is time to look at some of the technical specifications in more detail. An important criterion of power amplifiers is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio describes how much hum or hiss the amp is going to add to the audio signal. This ratio is usually shown in decibel or "db" for short.
You can do a simple comparison of the amp hiss by short circuiting the amp input, setting the gain to maximum and listening to a speaker connected to the amplifier. You will hear some amount of hissing and/or hum coming from the loudspeaker. This hiss is created by the amp itself. Then compare different amps according to the next rule: the smaller the level of hiss, the better the noise performance of the amp. Yet, bear in mind that you should put all amps to amplify by the same level in order to compare several amps. When glancing at the amp specification sheet, you want to look for an amp with a high signal-to-noise ratio figure which suggests that the amp outputs a small amount of hiss. One of the reasons why amps create noise is the fact that they use elements such as transistors and resistors that by nature produce noise. The overall noise depends on how much hiss every component produces. Yet, the location of those components is also important. Elements that are part of the amp input stage are going to normally contribute most of the noise.
Many of modern amplifiers are based on a digital switching topology. They are referred to as "class-D" or "class-T" amps. Switching amps include a power stage which is constantly switched at a frequency of approximately 400 kHz. This switching noise may cause some level of loudspeaker distortion yet is typically not included in the the signal-to-noise ratio which merely considers noise between 20 Hz and 20 kHz.
The signal-to-noise ratio is measured by feeding a 1 kHz test signal 60 dB below the full scale and measuring the noise floor of the amp. The amplification of the amp is set such that the full output power of the amp can be realized. Then, the noise floor between 20 Hz and 20 kHz is calculated and the ratio to the full-scale signal computed. The noise signal at different frequencies is eliminated via a bandpass filter throughout this measurement.
One more convention to express the signal-to-noise ratio makes use of more subjective terms. These terms are "dBA" or "A weighted". You are going to discover these terms in a lot of amp parameter sheets. 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 barely heard. An A-weighted signal-to-noise ratio weighs the noise floor in accordance to the human hearing and is normally higher than the unweighted signal-to-noise ratio.
About the Author:
Go here in order to study extra materials concerning mini amplifiers. Furthermore, go and visit http://www.amazon.com/Bogen-100-WATT-AMPLIFIER/dp/B0057OCFLG.
No comments:
Post a Comment