It is easy to be baffled by the terminology which stereo amplifier model suppliers employ to express the performance of their models. I will clarify the meaning of a frequently utilized amp spec: "signal-to-noise ratio" in order to help you make an informed decision when getting a brand new amplifier.
Once you have chosen a range of amplifiers, it's time to explore several of the specs in more detail in order to help you narrow down your search to one product. Every amplifier is going to produce a certain amount of hiss as well as hum. The signal-to-noise ratio is going to help quantify the level of static created by the amp.
Comparing the noise level of different amps can be done quite easily. Just get together a number of products that you wish to evaluate and short circuit the inputs. Then set the amp volume to maximum and verify the level of static by listening to the loudspeaker. You will hear some amount of hissing and/or hum coming from the speaker. This noise is produced by the amplifier itself. Then compare different amplifiers according to the following rule: the lower the level of noise, the higher the noise performance of the amplifier. Yet, bear in mind that you have to put all amps to amplify by the same amount in order to evaluate several amplifiers.
While taking a look at the amplifier specification sheet, you want to look for an amp with a large signal-to-noise ratio figure which indicates that the amplifier outputs a low level of noise. Noise is created due to a number of factors. One factor is that modern amplifiers all use components like transistors along with resistors. Those components are going to produce some amount of noise. Mostly the elements that are located at the input stage of an amp are going to contribute most to the overall hiss. Consequently manufacturers generally will pick low-noise components whilst designing the amp input stage.
The majority of latest power amps are digital amps, also known as "class-d amps". Class-D amps employ a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. Because of this, the output signal of switching amps contain a fairly large level of switching noise. This noise component, however, is generally impossible to hear as it is well above 20 kHz. However, it can still contribute to loudspeaker distortion. Signal-to-noise ratio is generally only shown within the range of 20 Hz to 20 kHz. Therefore, a lowpass filter is utilized while measuring switching amplifiers to remove the switching noise.
The signal-to-noise ratio is measured by feeding a 1 kHz test tone 60 dB below the full scale and measuring the noise floor of the amp. The volume of the amp is set such that the full output wattage of the amplifier can be achieved. Then, the noise floor between 20 Hz and 20 kHz is calculated and the ratio to the full-scale signal calculated. The noise signal at other frequencies is removed via a bandpass filter throughout this measurement.
Often you will discover the expression "dBA" or "a-weighted" in your amp parameter sheet. A weighting is a technique of expressing the noise floor in a more subjective manner. This technique tries to examine in how far the amp noise is perceived by human hearing which is most sensitive to signals at frequencies at 1 kHz. 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.
Once you have chosen a range of amplifiers, it's time to explore several of the specs in more detail in order to help you narrow down your search to one product. Every amplifier is going to produce a certain amount of hiss as well as hum. The signal-to-noise ratio is going to help quantify the level of static created by the amp.
Comparing the noise level of different amps can be done quite easily. Just get together a number of products that you wish to evaluate and short circuit the inputs. Then set the amp volume to maximum and verify the level of static by listening to the loudspeaker. You will hear some amount of hissing and/or hum coming from the speaker. This noise is produced by the amplifier itself. Then compare different amplifiers according to the following rule: the lower the level of noise, the higher the noise performance of the amplifier. Yet, bear in mind that you have to put all amps to amplify by the same amount in order to evaluate several amplifiers.
While taking a look at the amplifier specification sheet, you want to look for an amp with a large signal-to-noise ratio figure which indicates that the amplifier outputs a low level of noise. Noise is created due to a number of factors. One factor is that modern amplifiers all use components like transistors along with resistors. Those components are going to produce some amount of noise. Mostly the elements that are located at the input stage of an amp are going to contribute most to the overall hiss. Consequently manufacturers generally will pick low-noise components whilst designing the amp input stage.
The majority of latest power amps are digital amps, also known as "class-d amps". Class-D amps employ a switching stage which oscillates at a frequency between 300 kHz to 1 MHz. Because of this, the output signal of switching amps contain a fairly large level of switching noise. This noise component, however, is generally impossible to hear as it is well above 20 kHz. However, it can still contribute to loudspeaker distortion. Signal-to-noise ratio is generally only shown within the range of 20 Hz to 20 kHz. Therefore, a lowpass filter is utilized while measuring switching amplifiers to remove the switching noise.
The signal-to-noise ratio is measured by feeding a 1 kHz test tone 60 dB below the full scale and measuring the noise floor of the amp. The volume of the amp is set such that the full output wattage of the amplifier can be achieved. Then, the noise floor between 20 Hz and 20 kHz is calculated and the ratio to the full-scale signal calculated. The noise signal at other frequencies is removed via a bandpass filter throughout this measurement.
Often you will discover the expression "dBA" or "a-weighted" in your amp parameter sheet. A weighting is a technique of expressing the noise floor in a more subjective manner. This technique tries to examine in how far the amp noise is perceived by human hearing which is most sensitive to signals at frequencies at 1 kHz. 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.
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