NAD Masters Series M50 Digital Music Player & M52 Digital Music Vault

"Physical discs are so 20th century," I wrote back in 2006, when I began experimenting with using, in my high-end rig, a computer as a legitimate source of music. These days I rarely pop a disc into my Ayre Acoustics C-5xeMP disc player, unless it's an SACD I want to hear, or a CD I haven't yet ripped into my library. But many audiophiles, even if attracted to the idea of using a file-based system as a primary music source, do not want a computer in their listening rooms. Nor do they want to be bothered by the fact that a computer demands too intimate a relationship with its user.

For such folks, a number of high-end audio companies now offer turnkey, one-box solutions. Larry Greenhill has written about Bryston's impressive BDP-1 and BDP-2 digital audio players; in October 2013 I reviewed Marantz's no-holds-barred Reference NA-11S1 network player; and elsewhere in this issue, Kalman Rubinson enthuses over the Sony HAP-Z1ES. But for the past few months I've been living with a file-playing system from NAD's top-line Masters Series, the M50 Digital Music Player, which costs $2499 and was premiered at the 2013 Consumer Electronics Show.

Inside the box: M50
NAD refers to the Masters Series M50 as a "software-defined product." It will play files with bit depths of 16 or 24, and with sample rates up to 192kHz. Like the Brystons, the M50 has only digital outputs, but includes HDMI as well as AES/EBU, and optical and coaxial S/PDIF. Unlike the Sony but like the Marantz, the M50 has no internal storage, but can be used with an external, Linux-formatted USB drive. It also has Ethernet and WiFi connectivity, and can even be configured to act as its own WiFi hotspot, for control by a tablet.

NAD promotes the M50 as "computer audio without the computer." Internally, however, the M50 is indeed based on a computer: a 32-bit, ARM Cortex-A8 processor running Linux and with 248MB of internal memory. But externally, the M50 looks like an attractive high-end CD player—it even has a slot mechanism on the front panel, below its blue fluorescent display.


Greg Stidsen, NAD's Director, Technology and Product Planning, told me that they started working on the M50 project in 2008. Rather than use a one-size-fits-all OEM file-playing system like uPnP/DLNA, they decided to go it alone, taking what Stidsen described as "a true high-end approach."

At the time this review was prepared, the M50 supported streaming from Rdio, Slacker, TuneIn, and WiMP (Norway), with hi-rez downloads available from Qobuz (France) and HighResAudio (Germany). Stidsen told me that by the time this issue appears on the newsstands, they expect to have Deezer, Juke, and HDtracks support. "With HDtracks, HighResAudio, and Qobuz," he emphasized, "NAD is supporting direct download of purchased high-resolution files to the M50/M52, bypassing the computer completely. This is our vision for this product: to make it simple to purchase, store, and enjoy Studio Master recordings without the complexity and compromise of computer audio."

Inside the box: M52
As well as network-attached storage (NAS), the M50 can be used with any drive plugged into its rear-panel USB port. For this review, however, NAD sent along the Masters Series M52 Digital Music Vault ($1999). This connects to the M50 via USB and appears to use proprietary formatting—when I connected it directly to my Mac mini, it wasn't recognized. But when the M52 is plugged into the M50 and turned on, three LEDs on the M52's front panel glow first red, then blue as each of the drives becomes ready.


"Each of the drives?" Yes—while the M52 offers two terabytes of storage, it actually uses three separate hard drives in a RAID 5 array. RAID stands for "redundant array of independent disks," the idea being that, rather than multiple drives being used to store more data, the same data are written to all of the drives, along with error checking data: If one fails, the data can still be recovered. RAID 5 offers a powerful safety margin, but its downside is that it requires at least three drives: the M52's 2TB storage actually requires three 1TB drives.

I went online to research hard-drive prices. Tiger Direct sells RAID-compatible drive bays for $259–$368, and three 2TB drives for between $89 and $129 each, not including S&H. In theory, you could brew up your own 2TB RAID 5 array for $600–$800. But that would involve the user and computer getting involved in that relationship thing again. The M52 has no fans, runs dead quiet, and visually matches the M50 and NAD's Master Series M51 Direct Digital DAC. In that context, $1999 seems an appropriate price for the M52.

There's an app for that
While the M50 can be operated from its front-panel controls or the supplied remote, the easiest way is to use the NAD Remote app for Android or iOS devices. I downloaded the app (v1.6.1) from the Apple App Store and loaded it onto my iPad 2. The app displays all the music files that can be played with the M50 (see screenshots), and also allows the M51's volume to be controlled. However, an RS-232 connection between the M50 and M51 is required for the latter to function. The app is also compatible with NAD's and PSB's sister brand Blusound components (review forthcoming).


Albums can be selected and played in their entirety with NAD's iDevice app. A white bar with a red base shows the progress of the selected song.

Once the M50 had been connected to my router with an Ethernet cable, it was recognized by our domestic network as "M50-606" and, as have the other network-connected players I've tried, it updated its firmware via the Internet. I turned on my iPad, the NAD app recognized the M50, and that—after I'd used the app to index the music files on the M52—was that.

A ripping good time
The M50's CD drive can be used both to rip and play CDs. (When a disc is inserted, the app lets you select a default action or be prompted which you prefer; if the M50 is used without an active M52 or USB mass-storage device, a CD will automatically be played.) It took the M50 10:29 to rip a CD lasting 60:59, a playing speed of just under 6x, and about twice that to transcode the ripped files to FLAC, which I'd selected as the default format. (WAV and 320kbps MP3 are also offered; the rips are always made first to temporary WAV files in the M52's Rips folder, then transcoded to the desired format and moved to the Music folder.) The M50 retrieves the metadata and album art from the Internet when the disc is inserted and the disc is ejected at the end of the rip. Rips are automatically indexed by the M50; if you select a song, then press Info on the app screen, a window opens with the artist and album info downloaded from

NAD had provided a small number of files with the M52, but rather than re-rip CDs that were already in my iTunes library, I copied them over the network from my Mac mini's drive. This was as easy as mounting the M50-606 icon on the Mac's desktop, dragging'n'dropping the files from the Mac's iTunes Media folder to the Shared-Music folder on the M52, and reindexing the songs with the iOS app. I transferred both CD-sourced files and hi-rez files with sample rates up to 192kHz—and, for grins, a couple of DFF-formatted DSD64 files. Though the DSD64 files could be seen residing on the M52 via the network, the iOS app didn't recognize them as being playable. Given the M50's nature as a "software-defined product," I would imagine that DSD playback might well be the subject of a future firmware upgrade. However, if that were to happen, I suspect that the DSD data could be output only via the M50's HDMI port.

More important for those of us who keep our music files in iTunes, as well as as its "native" formats—WAV, FLAC, MP3—the M51 will play all proprietary file formats used by iTunes: AIFF, ALAC, AAC, even purchased AAC.

NAD Electronics International
633 Granite Court
Pickering, Ontario L1W 3K1
(905) 831-6555

Kal Rubinson's picture

With regard to the value of the M52 compared to a NAS, I recently configured two 5-bay NAS-RAID boxes with three 4TB drives each and that nets me, in each box, about 7TB of redundant storage with room to expand to 12TB. The cost for each was about $1100 and setup was trivial. However, I can understand that some might find the prospect of such setup intimidating.

You mention the idea of the M50 recognizing and playing DSD via the HDMI, that would seem to be just a firmware modification since, in this case, the M50 would not be decoding or processing anything, just transmitting the file content. If so, nothing should stand in the way of a similar firmware modification also accommodating multichannel files (FLAC, DSD, etc.) from the same port. That would make the M50 an ideal manager for my networked system.

(This is an attempt to recall the details of a lost post.)

JRT's picture

Another alternative would be to install a VortexBox ISO on a PC. Since the ISO is a free download, that can be a very cheap solution if you have an older PC that has been replaced with a newer upgrade. VortexBox can be used for digital audio extraction (ripping), will automatically transcode to FLAC or other formats, download cover art, ID3-tag the files, and will serve those files to your networked media players, Mac OS-X system, Windows system, etc. Buy a couple of new large capacity USB HDDs, and use one to store the files, the use the other as a backup copy, and even out the mechanical wear by swapping them when new files are added.

Similarly, someone could buy themself a nice new laptop and install JRiver Media Center software on the older one (or maybe use your SqueezeBox Touch). Connect that to an Oppo BDP-105/105D universal optical disc player which includes facility for use as an external DAC, and has enjoyed very favorable reviews by Dr. Rubinson. A firmware upgrade allows a SqueezeBox touch to connect to an external DAC such as the aforementioned OPPO deck using asynchronous USB, else use S/PDIF. Or simply use a nice inexpensive asynchronous USB DAC like an Audioquest Dragonfly in the laptop.

Spend some of the money saved on music data files (regardless the recording medium), and/or better loudspeakers, and/or some excellent headphones, all of which would do more to improve playback as compared to spending a lot more money on a propietary player/server combo that may not be nearly as well supported in a few years when out of warranty and no longer current models.

If JRiver goes obsolete, it can be replaced with another inexpensive software package. VortexBox is based on a Linux distribution, under continuous improvement, and not likely to become obsolete in the near future, and regardless that the data files could be copied to another server. When the hardware eventually fails, it too can be simply replaced.

Kal Rubinson's picture

Since you mention the Oppo 105, that alone will do all the functions albeit with a clumsy interface (even with the iPad app) compared to the NAD, jRiver and, even, the SBT. However, it sees the music files on my network and is happy with all formats including DSD and multichannel. Too bad about the interface as that is what makes it uncompetitive.

wozwoz's picture

So this is a physical disc player designed for hi-res, and yet it doesn't play SACDs? Is that right? Makes no sense at all. Why would anyone buy a physical player today that doesn't also handle SACD?

John Atkinson's picture
wozwoz wrote:
So this is a physical disc player designed for hi-res, and yet it doesn't play SACDs? Is that right?

Yes, that's correct.

wozwoz wrote:
Makes no sense at all. Why would anyone buy a physical player today that doesn't also handle SACD?

I suspect that it is because a) as I understand it there is now just one source for transport mechanisms that can play SACDs and manufacturers are not comfortable without multiple suppliers for essential parts; b) the market for SACDs is now small and not growing; and c) NAD feels file playback will become predominant.

John Atkinson
Editor, Stereophile

wozwoz's picture

Doesn't really make sense -

FIRST: even cheapie Universal players for the living room can play SACDs (and DVDs and Blu-ray and CD). So, designing a supposedly hi-res player that cannot play the dominant hi-res format seems like a peculiar business decision at best, and a simple blunder at worst.

SECOND: I do agree that the market for hi-res is tiny, but I would not agree that it is not growing. At least SACDs actually sell, and the demand for them shows no sign of abating ... Indeed, there are almost 10,000 titles out now, which is more than any other hi-res format (physical or downloads) and they keep on coming. The demand is certainly there - just check out the prices people pay on Amazon and ebay (in the hundreds of dollars) for discs that have sold out.

THIRD: many new SACD players (like those from Marantz and Luxman) not only play your CDs and SACDs, but also serve as an external DAC for hi-res playback from your computer if you want to play download files. Which is exactly the point: the NAD player is missing out on what the competition is offering.

seanh1978's picture

Does anyone know why this was discontinued ?

Based purely on sonics which is the better player M50 or Marantz ?

Bruce D. Goose's picture

It is a little unusual for the m-52 to have been discontinued given that the m-50 it was designed to work with is still available, and NAD's marketing literature promotes them as an ideal combination (and they are!). I own both units and here's my opinion:

Hard drive-based dedicated audio music servers have an Achilles heel: the hard drive! Notice how many of the newer ones no longer include any hard drive? Add it yourself via usb, but the manufacturer is then no longer responsible for warranty service. Hard drives are inherently unreliable over a typical two or three year warranty period, which is common for a hi-end piece.

Some anecdotal evidence: every one of the four (!) harman-kardon dmc-1000 music servers that i have owned has had a bad hard drive, though only one of the four was brand new. The NAD m-52 i bought was also bad out-of-the-box, but it will be repaired under warranty. I should say this was a demonstrator and NAD has been helpful, but i suspect that unacceptable warranty repair rates may be the real reason for the lack of more integrated hard drive systems, and why for NAD the m-52 is gone but the m-50 remains.

BTW, sound of the m-50+m-52 is clearly superior to the sound from usb sticks. Too bad nad never makes this clear,as they might have had more takers for the m-50, which is often positively discussed in a usb-stick context.