To help you select a stereo amplifier model, I will explain the expression "signal-to-noise ratio" which is commonly utilized to depict the performance of audio amplifiers.
Once you have selected a range of amps, it is time to explore a few of the specifications in more detail to help you narrow down your search to one product. The signal-to-noise ratio is a rather essential parameter and shows how much noise or hiss the amplifier produces.
Evaluating the noise level of several amps can be done rather easily. Simply gather several versions which you wish to compare and short circuit the inputs. Afterward put the amplifier gain to maximum and check the level of static by listening to the loudspeaker. You are going to hear some amount of hissing and/or hum coming from the speaker. This hiss is created by the amp itself. Make certain that the volume of the amplifiers is set to the same amount. Otherwise you will not be able to objectively evaluate the amount of noise between several amplifiers. The general rule is: the lower the amount of hiss that you hear the better the noise performance.
If you prefer an amplifier with a small amount of hissing, you can look at the signal-to-noise ratio number of the data sheet. The majority of makers will display this figure. amplifiers with a high signal-to-noise ratio are going to output a small level of noise. One of the reasons why amplifiers make noise is the fact that they utilize components such as transistors and resistors which by nature create noise. Mostly the elements that are situated at the input stage of an amplifier will contribute most to the overall hiss. Therefore makers typically will select low-noise components while developing the amplifier input stage.
Most of today's power amplifiers are digital amplifiers, also called "class-d amps". Class-D amplifiers use a switching stage that oscillates at a frequency in the range of 300 kHz to 1 MHz. This switching noise may cause some level of loudspeaker distortion but is typically not included in the the signal-to-noise ratio which only considers noise between 20 Hz and 20 kHz.
The signal-to-noise ratio is measured by inputting a 1 kHz test signal 60 dB underneath the full scale and measuring the noise floor of the amp. The amplification of the amplifier is set such that the full output wattage of the amp can be achieved. Next, 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 during this measurement.
Frequently the signal-to-noise ratio is shown in a more subjective way as "dbA" or "A weighted". This method tries to examine in how far the amplifier noise is perceived by human hearing which is most sensitive to signals at frequencies at 1 kHz. Thus an A-weighting filter is going to amplify the noise floor for frequencies which are easily heard and suppress the noise floor at frequencies which are barely heard. Many amps are going to have a larger A-weighted signal-to-noise ratio than the un-weighted ratio.
Once you have selected a range of amps, it is time to explore a few of the specifications in more detail to help you narrow down your search to one product. The signal-to-noise ratio is a rather essential parameter and shows how much noise or hiss the amplifier produces.
Evaluating the noise level of several amps can be done rather easily. Simply gather several versions which you wish to compare and short circuit the inputs. Afterward put the amplifier gain to maximum and check the level of static by listening to the loudspeaker. You are going to hear some amount of hissing and/or hum coming from the speaker. This hiss is created by the amp itself. Make certain that the volume of the amplifiers is set to the same amount. Otherwise you will not be able to objectively evaluate the amount of noise between several amplifiers. The general rule is: the lower the amount of hiss that you hear the better the noise performance.
If you prefer an amplifier with a small amount of hissing, you can look at the signal-to-noise ratio number of the data sheet. The majority of makers will display this figure. amplifiers with a high signal-to-noise ratio are going to output a small level of noise. One of the reasons why amplifiers make noise is the fact that they utilize components such as transistors and resistors which by nature create noise. Mostly the elements that are situated at the input stage of an amplifier will contribute most to the overall hiss. Therefore makers typically will select low-noise components while developing the amplifier input stage.
Most of today's power amplifiers are digital amplifiers, also called "class-d amps". Class-D amplifiers use a switching stage that oscillates at a frequency in the range of 300 kHz to 1 MHz. This switching noise may cause some level of loudspeaker distortion but is typically not included in the the signal-to-noise ratio which only considers noise between 20 Hz and 20 kHz.
The signal-to-noise ratio is measured by inputting a 1 kHz test signal 60 dB underneath the full scale and measuring the noise floor of the amp. The amplification of the amplifier is set such that the full output wattage of the amp can be achieved. Next, 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 during this measurement.
Frequently the signal-to-noise ratio is shown in a more subjective way as "dbA" or "A weighted". This method tries to examine in how far the amplifier noise is perceived by human hearing which is most sensitive to signals at frequencies at 1 kHz. Thus an A-weighting filter is going to amplify the noise floor for frequencies which are easily heard and suppress the noise floor at frequencies which are barely heard. Many amps are going to have a larger A-weighted signal-to-noise ratio than the un-weighted ratio.
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