Audio amplifiers

right|thumb|A megaphone thumb|An electric megaphone is used at a protest (Black Lives Matter, July 2021) thumb|An electric megaphone is used at a protest (Fight Trump, February 2018) thumb|A small sports megaphone for cheering at sporting events, next to a 75 mm cigarette lighter for scale

audio equipment that amplifies the signal strength of a device such as a CD player or an electric guitar, typically for feeding loudspeaker boxes connected to it

amplified sound system for public events

audio amplifier based on digital switching

circuit for amplifying microphone level audio signals

audio amplifier used with headphones

real, perceived or claimed quality of sounds from vacuum tube amplifiers