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Are you looking to acquire a new amp for your home loudspeakers? You may be dazzled by the number of options you have. To make an informed selection, it is best to familiarize yourself with common terms. One of these specs is known as "signal-to-noise ratio" and is not frequently understood. I will help explain the meaning of this expression. Once you have narrowed down your search by taking a look at several basic criteria, such as the level of output power, the dimensions of the amp plus the cost, you will still have quite a few products to choose from. Now it is time to look at a couple of the technical specifications in more detail. One important criterion of power amps is the signal-to-noise ratio. To put it simply, the signal-to-noise ratio explains how much hum or hiss the amp is going to add to the music signal. This ratio is commonly described in decibel or "db" for short.

While looking for an amp, you first are going to check the price, power among other basic criteria. Yet, after this initial selection, you will still have quite a few models to choose from. Now you are going to concentrate more on some of the technical specifications, such as signal-to-noise ratio and harmonic distortion. The signal-to-noise ratio is a fairly important parameter and describes how much noise or hiss the amplifier produces.

Whilst taking a look at the amplifier spec sheet, you want to look for an amp with a large signal-to-noise ratio figure which suggests that the amplifier outputs a low level of hiss. Noise is generated due to several reasons. One reason is that today's amps all employ components such as transistors and resistors. These elements are going to create some amount of hiss. Generally the elements that are situated at the input stage of an amplifier will contribute most to the overall noise. Therefore manufacturers typically will pick low-noise components while designing the amplifier input stage.

While looking at the amplifier spec sheet, you want to look for an amp with a high signal-to-noise ratio number which indicates that the amp outputs a low level of static. One of the reasons why amps make noise is the fact that they utilize elements such as transistors as well as resistors that by nature create noise. As the amp overall noise performance is mostly determined by the performance of elements situated at the amp input, manufacturers will try to select low-noise components while developing the amplifier input stage.

The majority of today's power amps incorporate a wattage switching stage that switches at a frequency around 500 kHz. Because of this, the output signal of switching amps have a fairly big amount of switching noise. This noise component, however, is typically impossible to hear since it is well above 20 kHz. Though, it can still contribute to speaker 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 amps in order to remove the switching noise. Manufacturers measure the signal-to-noise ratio by setting the amp such that the full output swing can be realized and by inputting a test signal to the amp that is generally 60 dB below the full scale of the amp. After that, the noise floor between 20 Hz and 20 kHz is measured and the ratio to the full-scale signal computed. The noise signal at different frequencies is removed through a bandpass filter throughout this measurement.

Often you are going to find the expression "dBA" or "a-weighted" in your amplifier spec sheet. A weighting is a technique of showing the noise floor in a more subjective manner. This method attempts to evaluate in how far the amplifier 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 usually higher than the unweighted signal-to-noise ratio.