Power amplifier producers frequently present the frequency response of their products and solutions that, sadly, won't automatically tell you a great deal regarding the audio quality. I will describe the meaning of this term and additionally offer some recommendations on how to interpret it while searching for an amp.
An amp is designed to amplify a music signal enough to drive some audio speakers to moderate or high volume. Manufacturers usually publish the frequency range over which the amp operates. This range is specified by showing 2 frequencies: a lower in addition to upper frequency. For example, the lower frequency might be 20 Hz and the higher frequency 20 kHz. Using this specification it seems like the amplifier can work as a HIFI amp. You might think the larger the frequency response the higher quality the amp. That, on the other hand, might not necessarily be. You have to glance at the specifications a lot more meticulously to correctly interpret all of them. A large frequency response doesn't imply the amp has good audio quality. By way of example an amplifier that has a frequency response between 30 Hz and 15 kHz may sound much better than another amplifier with a response between 10 Hz and 30 kHz. In addition, every producer, it appears, uses a different technique for specifying the lowest and highest frequency of their amps. The conventional convention is to display the frequency range within which the gain is going to drop a maximum of 3 dB from the nominal gain.
However, a few makers push this standard to the limit and often will show a maximum frequency where the amp is going to barely deliver a signal anymore. Also, just examining these 2 numbers will not say a lot concerning the linearity of the frequency response. Ideally you ought to try to get a frequency response diagram from the producer. In this chart, you will see the way the amp functions within the frequency response range. You can even spot any peaks or valleys the amp could have. Peaks along with valleys can cause colorization of the music. Preferably the amplifier should have a constant gain inside the complete frequency response aside from the drop off at the upper and lower limit. In addition to the frequency response, a phase response chart may also tell a whole lot regarding the overall performance and sound quality of the amp. You also need to look at the conditions under which the frequency response was determined. You generally are not going to find any information about the measurement conditions, however, in the producer's data sheet. The fact is that a large number of amplifiers will behave differently with different loudspeaker loads. This is mainly because that different speaker loads will result in changes to the behavior of the output power stage of the amp.
The circumstances under which the frequency response was determined may also be crucial to understand. The fact is that a lot of amps will behave differently with different speaker loads. This is because that different speaker loads will cause changes to the behavior of the output power stage of the amp.
Mainly current digital or "Class-D" amplifiers will show changes in the frequency response with different loads. The reason is the fact that Class-D amps employ switching FETs as the power stage that produce a great deal of switching components. These components are removed by a filter that is part of the amp. However, the frequency response of the amp now is dependent upon the loudspeaker load because the behavior of this lowpass filter is affected by the load impedance. Generally the lower the speaker load impedance the lower the upper cut-off frequency of the amplifier Some amp topologies provide a mechanism to compensate for changes in the amplifier gain with different loudspeaker loads. One example of these methods utilizes feedback. The amplifier output signal following the internal lowpass is input to the amplifier input for comparison. If not designed properly, this technique might cause instability of the amplifier though. Yet another method is to provide specific outputs for various loudspeaker impedances that are connected to the amplifier power phase through audio transformers.
An amp is designed to amplify a music signal enough to drive some audio speakers to moderate or high volume. Manufacturers usually publish the frequency range over which the amp operates. This range is specified by showing 2 frequencies: a lower in addition to upper frequency. For example, the lower frequency might be 20 Hz and the higher frequency 20 kHz. Using this specification it seems like the amplifier can work as a HIFI amp. You might think the larger the frequency response the higher quality the amp. That, on the other hand, might not necessarily be. You have to glance at the specifications a lot more meticulously to correctly interpret all of them. A large frequency response doesn't imply the amp has good audio quality. By way of example an amplifier that has a frequency response between 30 Hz and 15 kHz may sound much better than another amplifier with a response between 10 Hz and 30 kHz. In addition, every producer, it appears, uses a different technique for specifying the lowest and highest frequency of their amps. The conventional convention is to display the frequency range within which the gain is going to drop a maximum of 3 dB from the nominal gain.
However, a few makers push this standard to the limit and often will show a maximum frequency where the amp is going to barely deliver a signal anymore. Also, just examining these 2 numbers will not say a lot concerning the linearity of the frequency response. Ideally you ought to try to get a frequency response diagram from the producer. In this chart, you will see the way the amp functions within the frequency response range. You can even spot any peaks or valleys the amp could have. Peaks along with valleys can cause colorization of the music. Preferably the amplifier should have a constant gain inside the complete frequency response aside from the drop off at the upper and lower limit. In addition to the frequency response, a phase response chart may also tell a whole lot regarding the overall performance and sound quality of the amp. You also need to look at the conditions under which the frequency response was determined. You generally are not going to find any information about the measurement conditions, however, in the producer's data sheet. The fact is that a large number of amplifiers will behave differently with different loudspeaker loads. This is mainly because that different speaker loads will result in changes to the behavior of the output power stage of the amp.
The circumstances under which the frequency response was determined may also be crucial to understand. The fact is that a lot of amps will behave differently with different speaker loads. This is because that different speaker loads will cause changes to the behavior of the output power stage of the amp.
Mainly current digital or "Class-D" amplifiers will show changes in the frequency response with different loads. The reason is the fact that Class-D amps employ switching FETs as the power stage that produce a great deal of switching components. These components are removed by a filter that is part of the amp. However, the frequency response of the amp now is dependent upon the loudspeaker load because the behavior of this lowpass filter is affected by the load impedance. Generally the lower the speaker load impedance the lower the upper cut-off frequency of the amplifier Some amp topologies provide a mechanism to compensate for changes in the amplifier gain with different loudspeaker loads. One example of these methods utilizes feedback. The amplifier output signal following the internal lowpass is input to the amplifier input for comparison. If not designed properly, this technique might cause instability of the amplifier though. Yet another method is to provide specific outputs for various loudspeaker impedances that are connected to the amplifier power phase through audio transformers.
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