Pure Digital Mastery

NAD’s M28 seven-channel amp utilises Purifi’s Eigentakt Class D wizardry to claim more power than the outgoing M27. Steve Withers reports

- Steve Withers

Audiophiles often turn their noses up at Class D amplification, feeling the nature of its 'on/off' approach loses the sonic fidelity delivered by linear Class A or Class A/B designs. Yet Class D has many benefits, not least of which is its remarkable efficiency, and NAD believes its latest implementation is the cream of the crop.

By licensing technology from Danish corp Purifi, a consortium of Class D gurus that includes Peter Lyngdorf, who not only owns Lyngdorf but previously owned NAD, the company claims to have cooked up an amp that offers the best of both worlds – one that combines the efficiency and power handling of Class D with the responsiveness and transparency of Class A/B.

This has long been NAD's ambition, of course. Its previous multichannel amplifier, the M27, was a Class D design using nCore modules from Dutch outfit Hypex.

In the new M28 (£4,000), Purifi’s Eigentakt amplifier modules replace Hypex's nCore, and are joined by NAD's power supply and input stage architecture, plus its Hybrid Digital technology that means 'the M28 is impervious to the loudspeaker load it is presented with.'

As for Purifi's Eigentakt amplification, this, we're told, addresses 'previously unknown' issues relating to the amp's output filter, and boasts an almost 'analog-like behaviour' in the unlikely event the amplifier is driven into clipping. NAD says a traditional Class D design can become unstable under such circumstances, but 'Eigentakt behaves more like Class A/B with benign clipping and an instant recovery.'