Its pure blue indicator is faithful to the tradition of the legendary Marantz Brand. The MA-9S1 is the ultimate monaural power-amplifier for driving even the most demanding modern speakers with absolute ease. It represents the perfect balance between new-age innovation and traditional quality, and verifies that our pioneering ideas of the celebrated Model 9 live on the MA-9S1.A legendary monaural power amplifier, introduced in 1961.Utilising an EL34 tube in the ultra linear parallel push-pull circuitry. It delivered an incredibly high output power, which was reference setting in those days. It is the first model carrying on its front panel, what has become, the traditional Marantz meter.