Headphone amplifiers with equalizer
Equalizer
— the presence of an equalizer in the design of the amplifier.Initially, the equalizer is a regulator that allows you to change the volume of the sound of individual frequency bands and thus adjust the overall colour of the sound. However, in headphone amplifiers, this function is usually implemented in software, as follows: the settings provide several preset equalizer settings (presets), between which the user can switch at will. These presets are often created for certain genres of music (Pop, Rock, Classical, etc.) or content types (Movie, Live Concert, etc.); so the listener doesn't have to fiddle with manual adjustments — just choose the option of their choice. However, in some models, the equalizer can also be controlled manually, including creating your own custom presets. And in tube devices (see the relevant paragraph), the equalizer controls can be completely analogue and provide only manual adjustment.
Separately, we note that it is customary to indicate this function only if there are at least three adjustment bands. So the presence of bass and treble controls (see the relevant paragraphs) is not yet considered a full-fledged equalizer.