Most audio component manufacturers have a DAC in their product lineup, and NAD is no exception. However, the NAD M51 is unusual in that it takes the incoming digital PCM bitstream and converts it directly to a PWM bitstream, which is then fed directly to the output. The idea has been around for about a decade, but the technology for implementing it was not fast enough in those early days. Now, with modern technology and techniques, NAD has produced what they call a "Direct Digital DAC", where the digital signal does not go through digital to analog conversion in the normal sense, but converted to PWM at 844 kHz sampling, with 35 bit word length. As you will see with the bench tests, the results are quite amazing, and the price is very affordable.