Marantz MA-9S2 Reference Monaural AmplifierDale Davies ▼ | July 16, 2009
Far more than massive current capability elegantly housed in brushed aluminum, the MA-9S2 thoroughly updates the performance of Marantz original Model 9. It's the culmination of more than 50 years effort in reproducing audio in the home. A major untertaking, the engineers at Marantz tore apart the MA-9S1 and redesigned it from the ground up to be even faster, with less noise, and more authority. The MA-9S2 represents over 50 years of expertise in amplifier circuitry, and sincere love of music.
Marantz began with the historic Model 9, improved that distinctive voice with the MA-9S1 and now there's the MA-9S2, the latest step in Marantz's pursuit of sonic accuracy. When you first see the MA-9S2, you'll be impressed with its clean yet purposeful look. The 35mm-thick aluminum chassis and double-layer bottom plate forms an extraordinary rigid structure. Copper coating isolated delicate internal circuitry from extraneous interference.
Power output is the same (300 watts into 8 ohms, 600 watts into 4) as that of the MA-9S1. This "double down" capability speaks directly to the MA-9S2's current delivery prowess and, consequently, its ability to absolutely control any loudspeaker. Although this brute force approach might be adequate for some, the S2 incorporates several advances designed to further improve sound quality.
First, the power supply. The toroid power transformer benefits from a newly-developed "dual hemisphere" design with acoustical isolation augmented by silicon steel and a damped aluminum case. This greatly reduces internal vibration and sets the stage for finer resolution of sonic nuances. Shottky barrier diodes provide rectification for the voltage amplification stage to eliminate subtle ripples that can negatively impact overall clarity. Finally, the storage capacitor bank so important for the current amplification stage is 50% larger than that used in the S1 for even more prodigious yet superbly controlled bass response.
In addition to fully balanced differential topology, the S2 uses current feedback implemented with six HDAM-SA modules for faster response and lower noise. Flexibility is a key element in the MA-9S2's appeal, too. Three switchable inputs (two single ended, one balanced) complement the biwire-capable WBT speaker outputs. The high-precision power meter lets you keep tabs on the amplifier. Or you can switch it off completely for concentrated listening. All in all, the S2 is a textbook example of meticulous engineering. As did the original, this contemporary masterpiece redefines the art of audio amplification. ■