Heard of it, quite some time back(around 1998): (http://www.stereophile.com/content/pure-digital-amplifiers)
Direct Digital Amplification
Looks like they are finally here (outside of cellphones), no more DACs. Anyone heard of it?
the M32 however, NAD is reinventing the integrated amplifier, as we know it. DirectDigital amplification combines all pre-amplification and power amplification functions into a single amplifying stage. With 150W x2, the M32 is a true digital amp (not just Class D) that is computer controlled and amplifies entirely in the digital domain, converting to analog only at the speaker terminals. This gives it the shortest signal path possible.
the M32 however, NAD is reinventing the integrated amplifier, as we know it. DirectDigital amplification combines all pre-amplification and power amplification functions into a single amplifying stage. With 150W x2, the M32 is a true digital amp (not just Class D) that is computer controlled and amplifies entirely in the digital domain, converting to analog only at the speaker terminals. This gives it the shortest signal path possible.