To S. Andrea Sundaram,

So I just bought a new NAD M51 DAC and hooked it up to my Oppo BDP-105 / Emotiva XPR-2 / Salk SoundScape 8 system. I'm using the M51 as a digital preamp so as to avoid the Oppo's DAC, hopefully.

I have a connectivity issue.

The NAD M51 owner's manual says the following about the single XLR input on the rear panel called AES/EBU:

“Digital audio stream from professional audio sources like SACD/CD players or processors can be connected to this XLR connector.

“For high-end sources with higher sampling rates like 176kHz and 192kHz, it is highly recommended that such sources be interfaced with the AES/EBU IN connector. The AES/EBU IN is well suited to handle such sources with high sampling rates.”

The problem is the Oppo BDP-105 uses HDMI outputs so I can't follow NAD's recommendation to feed it using the AES/EBU connection (a single XLR feed). The implication is that I can't really get full hi-rez from the Oppo because the connector isn't right.

So I'm complaining to Crutchfield about this, but to be honest I'm not sure what I'm talking about.

Question: Is the lack of an AES/EBU connection from the Oppo BDP-105 to the NAD M51 having a deleterious effect on signal transmission, particularly with respect to hi-rez material?

Thank you,
Tony Parks

The short answer is not to worry about it. There are some theoretical advantages to AES/EBU over the coaxial connection, and optical connections don't always reliably support sample rates above 96kHz. HDMI, on the other hand, is perfectly capable of delivering high sample rates. Furthermore, due to copy protection, HDMI will be the only way to get full 96kHz or 192kHz off many Blu-ray or DVD-Audio discs. If using either of the latter, be sure to select the "Stereo LPCM” audio option (which is required to be included on all Blu-ray Discs), because the M51 will not decode multichannel data. Once you have it set up, let us know what you think of the M51. . . . S. Andrea Sundaram