The MM7055 from Marantz belongs to the family of solid stereophonic power amplifiers. The power amplifier is a device that accepts the signal from the respective source (cd/dvd player, turntable, radio, etc.), after it has passed through a pre-amplifier. It then amplifies it properly and transfers it to the speakers for playback. For this reason, power amplifiers usually only have the on/off button. In this case, it operates with transistors or otherwise solid state. The power is 140W/8Ω.