In our opinion, the NAD M51 has been the most exciting product to come from NAD in a long while. It can be used as a DAC or as a preamp if you're running only digital sources. With the addition of HDMI, it can even be used as a basic 2.0 video preamp. It is important to note that all signals that enter the M51 are resampled into PWM using extremely high sampling rates. The result is a very well balanced and natural sound. Highly recommended.
This particular one was sold to a regular customer of ours but never opened. He traded it back to us unopened and never used. We're selling it with our 90 day warranty.