The C 165BEE uses Class A grain modules to reduce noise and distortion, features fast transient response, and it can produce bass extension and smooth higher frequencies.  The C 275BEE uses 4 and 8 ohms of power to send 150 Watts to each of its two channels.  It uses PowerDrive, a proprietary NAD technology, to adjust its power settings to handle any impedance level from any speaker.