Through self-clocking and a modification of the output stage, Purifi and NAD succeeded in reducing the so-called hysteresis effect of the output filter in the feedback loop by more than 75 dB. In combination with their HybridDigital concept, the distortion content and background noise were reduced to a minimum. The distortion content was so low that NAD had no choice but to develop its method of measuring the distortion factor, which is only 0.00017% at 100 W. A revision of the self-oscillating CLASS-D technology also makes the M28 comparatively insensitive to changing speaker loads. Its extremely low output impedance also provides for the very high damping factor, which ensures a firm grip in the lower frequency range. When driving all channels, the amplifier has a continuous power of 200 W per channel at 8 ohms and 340 W at 4 ohms speakers. The circuit, known by NAD as PowerDrive, guarantees plenty of power reserves and even allows up to 560 W pulse power or seven times 280 W in single-channel operation. Both gold-plated Cinch and balanced XLR inputs are available. The M28 provides an impressive dynamic range and offers a virtually distortion-free surround sound performance that is second to none.
