In the world of audio amplifiers, wide kinds of semiconductor amplifiers, tube amplifiers, etc. are released. Therefore, the respective audio features can be enjoyed as a hobby.　Especially the tube power amplifiers has a tube called "fine tube" having a reputation for sound quality and last year we have developed the monaural power amplifier, MA-2000 composed by a parallel single-ended circuit adopting 300B which is the best tube among them and a circuit strongly driven by a transformer-coupled circuit adopting 2A3."
 
This year to tell many people the significance of MA-2000, we developed a new monaural power amplifier MA-1500 which has a plentiful 10W output along with an operation due to the transformer-coupled circuit which is single-operating with a 300B single tube.