The M1 enjoys all of the attributes of Anthem's award-winning Statement Class AB amplifiers but through exclusive Anthem technologies, goes far beyond the current capabilities of Class A, Class AB and prior Class D amplifiers in the market. The proprietary design employs all of the advantages of a Class D amplifier — high output, high efficiency, compact size — while avoiding the typical Class D limitations such as difficulty driving low-impedance (high-end) speakers, power line contamination, reliability issues and substandard audio quality. The absence of accurate dynamics is so common that it frequently goes unnoticed, but through the M1, music and movies are delivered with breathtaking realism.
Addressing the Class D bias
The “D” in Class D does not stand for digital. It was simply the fourth type of amp recognised and classified by the IEEE. The first was Class A, the second Class B, the third Class C, etc. Contrary to the bias that exists among high-end enthusiasts and across the industry in general, the Class D design is not inherently flawed. The truth is that no existing designs have been able to reach the Class D's inherent potential for performance. It is not the technology that yields fine audio performance but rather the implementation of the technology. At Anthem, they agree that most Class D amplifiers are poor performers. However the M1 uses Class D amplification of a different ilk (see later section on Class D for a full discussion).
The M1 is not a digital amp!
There are no A/D or D/A converters in the signal path. The amplifier’s control system continuously varies the width of the output pulse train in direct relation to the analog input signal. In essence, a side-to-side variation in width is analogous to a signal’s more familiar up-and-down amplitude variation, not at all the same as a digital string of 1s and 0s where all pulses have the same width.
Much has been written about Class D amps having twice the efficiency of conventional amplifiers at full output, but there's more to this. Under normal conditions an amplifier operates at only a fraction of its full output capability. At 1/8th of its maximum output (the typical working level of an amplifier), Anthem's M1 is six times more efficient than a conventional amplifier.
Never judge an amp by its size or its rack space
Amplifiers are often judged by their size and weight, the beefier the better since more power requires a physically heavier, larger amplifier. Or does it? It all depends on the design. When rack-mounted, the 20-kb M1 occupies only one rack space but despite its size can deliver 1,000W into 8 ohms and 2,000W into 4 ohms.
The M1’s cooling system quickly and efficiently moves heat from the interior of the amplifier to exterior heat sinks. Sealed copper pipes within the amp contain a small amount of special fluid held under a vacuum. When the temperature at one end of the pipe rises — the end adjacent to the amplifier's heat sources — the fluid in that end evaporates. This vapor is then naturally drawn to the cooler end of the pipe, along the heat sink on the side of the amp’s chassis where it condenses. From there a copper wick returns the fluid to the hotter end of the pipe. This heat transfer process is many thousands of times faster and more efficient than cooling through metal heat sinks alone. This system eliminates the need for fans, allowing multiple M1s to be stacked with no danger of overheating. It also means the amplifier is so mechanically quiet it will suit even the quietest listening rooms.