NAD M51 Direct Digital DAC


In Use

I used the M51 with an OPPO BDP-95 universal player, Classé CP-80 preamplifier, Classé CA-5200 power amplifier, and Threshold ES-500 electrostatic speakers. Cables were Emotiva, Wireworld, and Marc Audio.

I did most of my listening before the bench tests, but after seeing the distortion measurements, I did the remainder of my listening using the HDMI out from the OPPO to the HDMI-1 input on the M51.

Perhaps Debussy's most well-known piece is "Clair de Lune", but he did compose many very beautiful works, including the music on this Telarc SACD. The amount of detail that the M51 provided was breathtaking. Overall, the presentation was neutral. There was no emphasis on any particular part of the audio spectrum. I used the volume control on the M51 to fine tune the loudness, and I did not notice any loss of detail, which is one of the features of having a 35 bit PWM signal.












Although this is not the best version of the 1812 Overture, nevertheless, it is a good demo disc for dynamics, and the M51 delivered. The cannon shots at the end go very deep, and everything that was on the disc came out of the speakers. There was no evidence of any overload distortion. I should say here, that when I bench tested the M51, if I used a 0 dBFS test signal, and the M51 volume control was set to 0.0, there was some digital clipping. This is common with 0 dBFS signals feeding a DAC, and is why music digital recordings usually don't go near the 0 dBFS mark, but stay at least - 5 dB below that, so as to avoid clipping. However, for really dynamic recordings, including the 1812 where there are special effects such as the cannon shots, I would suggest turning the M51 volume control down to - 1 dB. This will eliminate the digital clipping - if any should occur. The ability to control the volume digitally on the M51 without truncating the LSB is unique, and extremely useful.













I would be at a loss if I could not retire to Baroque music to relax with, especially after experiencing cannon shots with signal that must have gone down to 10 Hz at least, and Scarlatti is one of my favorites. Stringed instruments will easily lose clarity if there is significant harmonic or IM distortion, and as you will see, the M51 has very low amounts of this contamination. The music was splendid, and so went my afternoon, with this album and more of same.