It is easy to be perplexed by the terminology which amplifier suppliers utilize in order to express the performance of their models. Next you will focus more on a number of of the technical specifications, like signal-to-noise ratio in addition to harmonic distortion. You can do a simple comparison of the amp hiss by short circuiting the amplifier input, setting the gain to maximum and listening to a loudspeaker connected to the amp. Next compare several mini audio amps according to the next rule: the lower the level of hiss, the higher the noise performance of the amp. On the other hand, bear in mind that you have to put all amps to amplify by the same amount to compare different amps.
To help you compare the noise performance, amplifier producers publish the signal-to-noise ratio in their amplifier spec sheets. There are numerous reasons why power amps is going to add some form of hiss or other unwanted signal. However, latest amp specifications typically only consider the noise between 20 Hz and 20 kHz.
Next the level of the noise energy in relation to the full-scale output wattage is computed and shown in db.
Frequently you are going to discover the term “dBA” or “a-weighted” in your amp spec sheet.