Are you looking to get a new amp for your home speakers? You may be dazzled by the number of options you have. To make an informed selection, it is best to familiarize yourself with popular specs. One of these specs is named "signal-to-noise ratio" and is not frequently understood. I will help clarify the meaning of this expression.
As soon as you have chosen a range of amplifiers, it's time to investigate a few of the specs in more detail in order to help you narrow down your search to one model. Each amp will make a certain level of hiss and hum. The signal-to-noise ratio is going to help compute the level of static produced by the amp.
If you prefer an amp with a small amount of hissing, you can look at the signal-to-noise ratio number of the data sheet. Most manufacturers are going to display this figure. Amplifiers with a large signal-to-noise ratio will output a low level of noise. Noise is produced due to several reasons. One reason is that modern amplifiers all employ components including transistors in addition to resistors. Those components are going to make some amount of hiss. Generally the components that are situated at the input stage of an amplifier are going to contribute most to the overall noise. Thus producers normally will pick low-noise components when developing the amplifier input stage.
Many today's power amplifiers include a power switching stage that switches at a frequency around 500 kHz. In consequence, the output signal of switching amps have a moderately large level of switching noise. This noise component, however, is usually inaudible since it is well above 20 kHz. However, it may still contribute to loudspeaker distortion. Signal-to-noise ratio is typically only shown within the range of 20 Hz to 20 kHz. Therefore, a lowpass filter is used when measuring switching amps in order to eliminate the switching noise.
Makers measure the signal-to-noise ratio by means of setting the amplifier such that the full output swing can be achieved and by feeding a test signal to the amplifier that is usually 60 dB underneath the full scale of the amp. Subsequently, only the noise between 20 Hz and 20 kHz is considered. The noise at other frequencies is eliminated via a filter. Then the level of the noise energy in relation to the full-scale output power is computed and expressed in decibel.
An additional convention to express the signal-to-noise ratio uses more subjective terms. These terms are "dBA" or "A weighted". You are going to spot these terms in most amp parameter sheets. This technique was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most sensitive to signals around 1 kHz. Though, signals under 50 Hz and above 13 kHz are barely heard. The A-weighted signal-to-noise ratio is usually higher than the unweighted ratio and is shown in the majority of amplifier spec sheets.
As soon as you have chosen a range of amplifiers, it's time to investigate a few of the specs in more detail in order to help you narrow down your search to one model. Each amp will make a certain level of hiss and hum. The signal-to-noise ratio is going to help compute the level of static produced by the amp.
If you prefer an amp with a small amount of hissing, you can look at the signal-to-noise ratio number of the data sheet. Most manufacturers are going to display this figure. Amplifiers with a large signal-to-noise ratio will output a low level of noise. Noise is produced due to several reasons. One reason is that modern amplifiers all employ components including transistors in addition to resistors. Those components are going to make some amount of hiss. Generally the components that are situated at the input stage of an amplifier are going to contribute most to the overall noise. Thus producers normally will pick low-noise components when developing the amplifier input stage.
Many today's power amplifiers include a power switching stage that switches at a frequency around 500 kHz. In consequence, the output signal of switching amps have a moderately large level of switching noise. This noise component, however, is usually inaudible since it is well above 20 kHz. However, it may still contribute to loudspeaker distortion. Signal-to-noise ratio is typically only shown within the range of 20 Hz to 20 kHz. Therefore, a lowpass filter is used when measuring switching amps in order to eliminate the switching noise.
Makers measure the signal-to-noise ratio by means of setting the amplifier such that the full output swing can be achieved and by feeding a test signal to the amplifier that is usually 60 dB underneath the full scale of the amp. Subsequently, only the noise between 20 Hz and 20 kHz is considered. The noise at other frequencies is eliminated via a filter. Then the level of the noise energy in relation to the full-scale output power is computed and expressed in decibel.
An additional convention to express the signal-to-noise ratio uses more subjective terms. These terms are "dBA" or "A weighted". You are going to spot these terms in most amp parameter sheets. This technique was developed with the knowledge that human hearing perceives noise at different frequencies differently. Human hearing is most sensitive to signals around 1 kHz. Though, signals under 50 Hz and above 13 kHz are barely heard. The A-weighted signal-to-noise ratio is usually higher than the unweighted ratio and is shown in the majority of amplifier spec sheets.
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