To help you pick an audio amplifier, I am going to describe the expression "signal-to-noise ratio" which is usually utilized in order to depict the performance of audio amps. Once you have chosen a range of amplifiers, it is time to investigate a few of the specs in more detail in order to help you narrow down your search to one product. Each amplifier will make a certain amount of hiss and hum. The signal-to-noise ratio will help quantify the level of hiss produced by the amp.
Once you have narrowed down your search by taking a look at a few fundamental criteria, such as the level of output power, the dimensions of the amplifier plus the price, you are going to still have quite a few products to choose from. Now it is time to look at a few of the technical specs in more detail. The signal-to-noise ratio is a rather important parameter and explains how much noise or hiss the amplifier creates.
A way in order to perform a simple assessment of the noise performance of an amplifier is to short circuit the amplifier input and then to crank up the amp to its maximum. After that listen to the loudspeaker that you have attached. The noise that you hear is produced by the amplifier itself. Then compare several amplifiers according to the next rule: the smaller the amount of static, the higher the noise performance of the amplifier. On the other hand, keep in mind that you should put all amplifiers to amplify by the same level to compare different amplifiers. To help you compare the noise performance, amplifier producers show the signal-to-noise ratio in their amp specification sheets. Simply put, the larger the signal-to-noise ratio, the smaller the level of noise the amp produces. Noise is produced due to several reasons. One factor is that modern amps all use components such as transistors and resistors. Those elements are going to create some amount of noise. The overall noise is dependent on how much hiss every element generates. Nonetheless, the position of those components is also vital. Elements which are part of the amplifier input stage will generally contribute most of the noise.
The majority of today's power amplifiers incorporate a power switching stage which switches at a frequency around 500 kHz. This switching frequency is also noise which is part of the amplified signal. However, modern amplifier specifications usually only consider the noise between 20 Hz and 20 kHz.
Producers measure the signal-to-noise ratio by means of setting the amplifier such that the full output swing can be realized and by inputting a test tone to the amplifier that is typically 60 dB below the full scale of the amplifier. After that, 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 removed by a bandpass filter throughout this measurement.
Often you are going to find the term "dBA" or "a-weighted" in your amplifier specification sheet. A weighting is a technique of expressing the noise floor in a more subjective fashion. This technique was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most perceptive to signals around 1 kHz. Then again, signals under 50 Hz and higher than 13 kHz are barely noticed. The A-weighted signal-to-noise ratio is usually higher than the unweighted ratio and is shown in most amplifier parameter sheets.
Once you have narrowed down your search by taking a look at a few fundamental criteria, such as the level of output power, the dimensions of the amplifier plus the price, you are going to still have quite a few products to choose from. Now it is time to look at a few of the technical specs in more detail. The signal-to-noise ratio is a rather important parameter and explains how much noise or hiss the amplifier creates.
A way in order to perform a simple assessment of the noise performance of an amplifier is to short circuit the amplifier input and then to crank up the amp to its maximum. After that listen to the loudspeaker that you have attached. The noise that you hear is produced by the amplifier itself. Then compare several amplifiers according to the next rule: the smaller the amount of static, the higher the noise performance of the amplifier. On the other hand, keep in mind that you should put all amplifiers to amplify by the same level to compare different amplifiers. To help you compare the noise performance, amplifier producers show the signal-to-noise ratio in their amp specification sheets. Simply put, the larger the signal-to-noise ratio, the smaller the level of noise the amp produces. Noise is produced due to several reasons. One factor is that modern amps all use components such as transistors and resistors. Those elements are going to create some amount of noise. The overall noise is dependent on how much hiss every element generates. Nonetheless, the position of those components is also vital. Elements which are part of the amplifier input stage will generally contribute most of the noise.
The majority of today's power amplifiers incorporate a power switching stage which switches at a frequency around 500 kHz. This switching frequency is also noise which is part of the amplified signal. However, modern amplifier specifications usually only consider the noise between 20 Hz and 20 kHz.
Producers measure the signal-to-noise ratio by means of setting the amplifier such that the full output swing can be realized and by inputting a test tone to the amplifier that is typically 60 dB below the full scale of the amplifier. After that, 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 removed by a bandpass filter throughout this measurement.
Often you are going to find the term "dBA" or "a-weighted" in your amplifier specification sheet. A weighting is a technique of expressing the noise floor in a more subjective fashion. This technique was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most perceptive to signals around 1 kHz. Then again, signals under 50 Hz and higher than 13 kHz are barely noticed. The A-weighted signal-to-noise ratio is usually higher than the unweighted ratio and is shown in most amplifier parameter sheets.
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