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It’s here!!! NAD’s new M2 Direct Digital Amplifier.

Nov 17 2009 | Posted by: Kyle Grimm | Filed under Products

Hello everybody!

We are thrilled to announce that NAD has chosen Chelsea Audio Video to show one of the very first M2 Direct Digital Amplifiers available. Swing by any time for a demo of this amazing amplifier!

M2: "Inventing the future of audio"

"NAD's M2 is a triumph on many levels, not the least of which is that it points toward a new direction in amplifier design and system architecture. I predict that years from now audiophiles will look back on the M2 as the progenitor of the next generation of audio."

  — Robert Harley, The Absolute Sound

The NAD M2 Direct Digital Amplifier is a revolutionary new product that will take your music system to a whole new level of performance.

* Like three high performance components in one (preamp, power amp and Digital-to-Analog Converter)
* 2 x 250W Continuous Power at 8 and 4 Ohms
* >500W IHF Dynamic Power
* >120dB Dynamic Range
* Two sets of speaker binding posts to facilitate Bi-wiring

Superior to any previous digital amplifier, the M2 is really three high performance components in one (preamp, power amp and Digital-to-Analog Converter) and can directly drive your loudspeakers. The M2's technology is far more sophisticated than the Class D analog amplifiers that are often erroneously referred to as "digital." In fact, the M2 is the first digital amplifier that can match the best linear amplifiers for low noise and distortion, delivering better than Class A sound with Class D efficiency.

While the M2 can accept an analog signal like a traditional amplifier, it can also accept a digital one. With fewer internal amplification stages than a traditional preamp, the M2 maintains a purer signal chain. It is also capable of delivering startling power — 250 Watts to each of two channels at 4 or 8 Ohms continuous, and 500 Watts IHF Dynamic for those particularly demanding musical passages. As Robert Harley states in his recent glowing review in The Absolute Sound:

"Functionally, the M2 is an 'integrated amplifier' that replaces a DAC, preamplifier, and power amplifier. The M2 eliminates from a traditional signal path all the electronics of a DAC as well as the active analog gain stages of a preamplifier and power amplifier. It does this by converting the PCM signal from a digital source directly into a pulse-width modulation (PWM) signal that turns the M2’s output transistors on and off. That’s it—no digital filter, no DACs, no multiple stages of analog amplification, no interconnects, no jacks, no analog volume control, no preamp. The conversion from the digital domain to the analog domain occurs as a by-product of the switching output stage and its analog filter. This is as direct a signal path as one could envision."

In addition to a full complement of digital inputs, the M2 also has balanced XLR and single-ended analog inputs as well as two sets of binding posts for bi-wiring your speakers.

Feedback reinvented The concept of feedback is simple and brilliant. Compare the signal at the output of an amplifier with the signal at the input; any difference is caused by the distortion of the amplifier. Now, invert that difference signal and add it to the incoming signal and the difference signal will offset and cancel out the distortion. But for a digital amplifier, implementing this concept is anything but simple! As we have pointed out, the M2 takes a digital input signal and outputs an analog signal to drive the loudspeaker.

The conventional feedback architecture with a loop from the output to the amplifier’s input is too slow and not a successful approach with a digital amplifier, so the direct digital feedback technology was developed to deliver the solution. A feedback error signal is generated through comparison with an extremely pure reference and then converted to the digital domain at a 108MHz sample rate prior to being used for digital correction. This very direct feedback approach is at the heart of the M2 architecture.

Blinding speed and precision For Direct Digital Feedback to work correctly, there must be a very wide bit path and very high speed operation. The M2’s extremely wide 35-bit data path allows for compensation to be made without truncating any information in the original signal. Running from a master clock frequency of 108MHz there is enough speed to keep a very wide amplifier bandwidth and very low noise and distortion in the audio band.

Streamlined signal path Because the M2 Direct Digital Amplifier can accept a digital PCM input directly, the noise and distortion added by cascaded analog amplifying stages, as found in traditional Class AB or even Class D amplifiers, is completely eliminated. This streamlining of the system architecture can reduce the residual noise of the overall system by a factor of three.

Analog input section Because there are still analog sources, and because some users will want to use a traditional analog preamplifier with the M2, NAD has provided a state-of- the-art Analog-to-Digital converter stage. This fully balanced stage accepts both a Single Ended input and a Balanced XLR input. Both the analogue input buffer amp and the ADC are of the highest quality available today.

Digital processor loop This unique feature allows the advanced user to insert external digital filters into the signal path. Using the Optical Toslink format allows fuss-free connection to Macs and PCs where there is a wide library of crossover filters and room correction programs available.

Digital outputs in both coaxial and optical formats make it possible to use multiple M2s for bi- or tri-amplification of advanced loudspeaker systems.

Advanced power supplies The M2 uses three power supplies, all of them highly efficient switch mode types. Each channel gets its own high current power supply in a dual mono configuration. The Input stage and control sections get their own dedicated supply with multiple regulated secondary voltages for individual sections.

Highly effective control Digital PowerDrive™ optimizes the M2’s performance when driving real loudspeakers by maintaining optimum power delivery and lowest possible distortion. Unlike most digital amplifiers that do not have power reserves, the M2 has excellent dynamic power capabilities.

Digital Soft Clipping prevents the harsh sound and potential speaker damage that can result when a severely overdriven amplifier clips the tops and bottoms of the sine wave. Using digital precision, this behavior can be completely controlled by the M2. Multi-stage fail-safe protection is carefully engineered into the M2 to prevent amplifier or speaker damage under fault conditions. Short circuit, DC offset, overheat, and over current faults are handled instantly and an indication of the fault is displayed on the front panel.

An RS-232 serial interface allows the M2 to be controlled from the PC or via advanced control systems like Crestron and AMX. 12V Trigger and IR Input allow for other popular control options and add flexibility for home and studio use.

Thanks for Reading! Kyle

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