In the world of audio amplifiers, there is a wide range of types, from semiconductor amplifiers to vacuum tube amplifiers, each of which has its own advantages and can be enjoyed as a hobby for audios. In particular, there are several vacuum tube power amplifiers, such as 2A3 and 300B, which are known for their sound quality and are called "famous valves." Their sound quality has a quality that cannot be expressed by semiconductor amplifiers, and they are still strongly supported even today. This year, we have developed the MA-5000 as a monaural power amplifier to respond to the desire to experience the highest quality sound from a 211 amplifier. It uses highly reputed vacuum tube 211 at a parallel single output use, also uses 300B for the driver stage to drive the 211 powerfully by a transformer coupling.