Direct Digital DAC/Preamp: The NAD M51 Direct Digital DAC introduces
many "firsts" for the DAC product category: first to support HDMI, first to
support USB Audio Class 2 with support for 192kHz, the first to use digital
error correction, and the first 35-bit architecture to be found in a DAC. The
M51 is also a fully functional digital preamp with seven digital inputs and one
of the world's best volume controls. As a "preamp" it is totally noise and
distortion free, because all switching and volume control is done in the digital
domain. There are no analog circuits except for the Class A buffer at the output
of the DAC. Whether you want to get into computer audio, Home Cinema 2.0, or
just want to upgrade your CD player; the M51 Direct Digital DAC will get the
best possible performance from your digital formats. All this innovation,
performance, and flexibility come with NAD's legendary sound quality and
Direct Digital Technology: NAD's Direct Digital technology is unique
in both its extreme precision and in its speed. Direct Digital technology uses a
very powerful processing engine that operates at much higher speed and with much
greater accuracy than typical Digital-to-Analog converters. Running at 108MHz,
the M51 resamples the incoming pulse code modulated (PCM) signal and converts it
to a pulse width modulation signal (PWM) with a sampling rate of 844kHz.
Operating in a differential mode with double precision, the M51 has
state-of-the-art specifications for low noise and distortion free sound. The
extreme headroom afforded by the 35-bit architecture allows for a DSP-based
volume control that does not reduce resolution. Even with 24-bit high definition
signals, the output can be attenuated by 66dB (very quiet) before bit truncation
Precision Processing Engine:
The incredible precision of the
M51's processing engine gives music a vibrancy and transient accuracy
that must be heard to be appreciated. The conversion process from PCM to
PWM completely eliminates any jitter present on the incoming signal;
again, offering state-of-the-art performance in this most important
parameter. Due to the very high clock speed and mathematical precision
of our reconstruction filters, the resulting audio signal is totally
free of digital artifacts like ringing.
Pure Class A Analog Stage: A Pure Class A analog stage with
very low output impedance provides the perfect interface to your
favorite amplifier. Also, both balanced (XLR) and unbalanced (RCA)
outputs are available.
Power On/Off Switch: The NAD M51 direct digital DAC's main power
switch is located on the rear-panel. Once this main power switch is set to "On",
you can switch the NAD M51 from "On" to "Standby" using the front-panel On/Off
Input Selection: There is an Input Selection button on the M51's
front-panel which allows you to switch between connected sources (AES/EBU,
Coaxial, Optical, USB, HDMI, & HDMI2).
Remote Control: The supplied IR remote provides wireless operation of
the M51 and features controls for NAD's
matching M50 Digital Music Player (745M50, sold separately).
USB (Type-B) Port: The NAD M51 direct digital DAC is ready
for the world of computer audio with its rear-panel asynchronous USB (type-B)
input that can directly stream 24-bit/192kHz content from your Windows PC, Mac
computer, or other network-attached storage device (NAS). Your computer will
need to meet the following system requirements.
- Windows PC Users: Microsoft Windows XP Service Pack 2
or higher, Microsoft Windows 7.
- Mac Users: Minimum Mac OS X Snow Leopard (version 10.6)
and later versions.
Note: Download the "NAD USB 2.0 Audio Driver"
and install this driver to your Windows computer. Mac OS X Snow Leopard
(version 10.6) and later versions already include USB Audio 2.0 drivers (no
need to download NAD USB 2.0 Audio Driver).
Digital Audio Inputs: The NAD M51 Direct Digital DAC includes three
digital audio inputs; optical (Toslink), one coaxial (RCA), and one AES/EBU
- Digital AES/EBU (XLR) Input: The NAD M51 is fitted with a Digital
AES/EBU (XLR) jack to connect high-end audio sources, such as SACD and DVD-Audio
players. 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 (XLR) In connector.
- Digital Coaxial/Optical Inputs: The M51 also features a
rear-panel optical (toslink) digital input and coaxial (RCA) digital input to connect your digital audio components. Connect your CD, DVD, and Blu-ray
disc players. You can also add NAD's innovative C 446 Digital Media Tuner
(745C446, sold separately) to stream and manage your internet radio and NAS
devices, as well as local AM/FM broadcasts. The Digital inputs support
sampling rates of 32-192khz.
Note: If connecting to a television set's optical output, please
make sure that you are able to select PCM as the default optical out audio
format from your television's Audio menu. This DAC is not compatible with
multi-channel audio signals and will not work with televisions that do not
Analog Audio Outputs: The NAD M51 offers balanced (XLR) and unbalanced
(RCA) analog audio outputs.
- Balanced XLR Output: The M51 is fitted with a pair of balanced
XLR outputs to connect your high-end or professional audio amplifier.
- Unbalanced RCA Output: There is one set of unbalanced analog
stereo RCA outputs to connect to your stereo amplifier.
HDMI Inputs/Output: The M51 offers two HDMI v1.4 inputs and one HDMI v1.4
output with video pass-through. This opens up the possibility of using the M51
Direct Digital DAC as the heart of a "Video 2.0" system using the mandatory
two-channel linear PCM soundtrack from Blu-ray or DVD to make a compelling
two-channel high definition theater presentation. Many symphony orchestras and
some specialty music labels are also released in HD recordings on Blu-ray or
DVD. The M51 is fully 3D video compatible, but there is no surround sound
decoding or video processing.
USB (Type-A) Port: The M51's USB (type-A) port is only used to update
the unit with future software/firmware upgrades from NAD.
12V Trigger Inputs: With this 3.5mm input triggered by a 12V DC
supply, the M51 can be switched On remotely from standby mode by compatible
devices; such as amplifiers, preamplifiers, receivers, etc. If the 12V DC supply
is cut off, the M51 will return to standby mode.
IR Input: This 3.5mm input is connected to the output of an IR
(infrared) repeater (Xantech or similar) or the IR output of another component
to allow control of the M51 from a remote location.
RS-232 Port: The RS-232 port allows connection to a
compatible PC or external whole-house control system from companies such as AMX
or Crestron. NAD is a certified partner of AMX and Crestron and fully supports
these external devices.
AC Power Cord: The M5 comes supplied with a detachable
6' AC power cord.