NAD Masters Series M2 Direct Digital Amplifier Challenges Paradigms

Integrated amplifiers
NAD Masters Series M2 Direct Digital Amplifier Challenges Paradigms

Sharon, MA-based NAD Electronics today announced its new Masters Series M2 Direct Digital Amplifier—an amp whose circuit topology not only challenges many established paradigms, but that, NAD says, “sets new benchmarks for both measurable performance and subjective musical quality.” According to an NAD press release, the M2 “can be thought of as a Digital-to-Analog Converter (DAC) that directly drives a loudspeaker, but with the same precision as the very best low-level DACs.” The goal was for the M2 to become, “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.” The M2 is a stereo amplifier that can produce 2 x 250Wpc into 4 or 8 Ohms, with 500Wpc of IHF dynamic power on tap. The M2 will become available from NAD dealers this summer at an MSRP of $5999.

A Number of “Firsts”

NAD touts a number of “firsts” achieved by the M2 design, including these:

  • First digital amplifier to provide “a fully digital signal path” (though both single-ended and balanced analog inputs are also provided, backed by what NAD describes as “a fully balanced, state-of-the-art analog-to-digital converter”).
  • First digital amplifier to use “high-speed digital error correction to reduce distortion."
  • First digital amplifier to “fully implement digital closed-loop processing (a.k.a. error correction).”
  • First digital amplifier to “implement a new technology called Direct Digital Feedback developed by U.K.-based Diodes Zetex Semiconductors Ltd. during its collaboration with NAD on the M2 project.” The NAD press release explains that the M2 incorporates “a unique, custom implementation of Diodes Zetex's patented Direct Digital Feedback Amplifier™  (DDFA) architecture within a Xilinx field programmable gate array to provide a custom platform for blending DDFA technology with NAD's own innovations.”


More Design Details

Unlike most power amplifiers, which provide analog audio inputs only, the M2 provides a much more varied and extensive array of inputs, including two sets of stereo analog audio inputs (single-ended and balanced XLR), plus five sets of digital audio inputs (two coaxial, two optical, and one AES/EBU).  Moreover, in a sharp break with typical practice for most power amplifiers, the M2 provides “a DSP (engine that) is custom programmed with NAD's high-resolution digital volume control possessing a broad attenuation range and perfect channel balance.” The M3

One practical upshot of this design choice is that digital source components can be plugged into the M2 directly, obviating the need for a traditional preamp (though the M2 can accommodate preamps, if users so desire).

Interestingly, the M2 also provides “a five-position digital impedance compensation filter allows fine-tuning the top octave to match the selected speaker impedance, resulting in a perfectly flat frequency response at 20kHz.”

Finally, the M2 includes a “unique Digital Processor Loop(that)allows advanced users to insert external digital filters into the signal path.” NAD explains that one intended purpose of the loop is to allow PC and Mac users to access and apply wide libraries of available “crossover filters and room correction programs.”

The M2 certainly sounds interesting on paper; we can’t wait to evaluate the amplifier’s real-world performance once it is released later this summer. As the release date draws closer, watch for more information to become available at this site:

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