NAD C390DD Direct Digital DAC Amplifier


The NAD C 390DD is not only a new concept in amplification, but also in audio system architecture. First introduced in the now famous NAD M2 Direct Digital Amplifier, Direct Digital technology has been praised for its transparent, dynamic and detailed sound quality.


  • Like the M2, the C 390DD has no analogue stages in the signal path, keeping music in the digital domain right up to the speaker outputs. All preamp functions are executed in the digital domain without the phase shift, noise and distortion that plagues all analogue designs regardless of price or pedigree. Its 35-bit architecture and 108MHz master clock also make Direct Digital one of the most accurate DAC technologies available.

    The advantages of a pure digital system are many, but one drawback is the constantly changing delivery formats for digital content. Each of these formats typically requires specialized hardware and software, often with licensed IP and content copy protection.

  • For this reason, we place all digital interface circuitry on easily upgradable modules. We call this Modular Design Construction or MDC. The C 390DD comes standard with one module, the DD USB 1 for USB interface, and open slots for two more modules. Optional MDC modules currently include the DD HDM-1 HDMI Module and the DD AP-1 Analogue Phono module. The DD HDMI-1 offers three HDMI inputs and one output with video pass through. This opens up the possibility of using the C 390DD 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 theatre presentation. Many Symphony Orchestras and some specialty music labels are also released in HD recordings on Blu-ray or DVD. The DD HDMI-1 is fully 3D video compatible, but there is no surround sound decoding or video processing.

    The DD AP-1 module is also very innovative, using super high quality Analogue-to-Digital conversion to make analogue sources compatible with the C 390DD's pure digital circuitry. Using 24/192 processing, the ADC circuit auto-ranges for the best possible resolution and lowest noise. The phono circuit has impedance settings for both moving magnet (MM) and moving coil (MC) cartridges with gain automatically set.

    The C 390DD has a very high continuous power rating of 150 watts per channel with almost immeasurable distortion and noise. More importantly, thanks to NAD's exclusive Digital PowerDrive circuit sensing the speaker load and altering amplifier characteristics, power delivery into real loudspeakers is enhanced with the most efficient power delivery and best safety margin. Resulting in power output that can more than triple the rated power for short periods of time to accurately and effortlessly reproduce musical transients. The result is that the C 390DD sounds even more powerful than its already impressive continuous power rating.

    Since the C 390DD performs the functions of multiple conventional components, not only is the sound improved, but the way a music system is configured can change as well. The C 390DD is ready for the world of computer audio with its asynchronous USB input that can directly stream 24/96 content from your PC or Mac, USB memory sticks and hard drives (Fat32) are also supported with both front and rear connections. Or add NAD's innovative C 446 Digital Media Tuner to stream and manage your internet radio and NAS devices as well as local FM and AM broadcasts. Naturally, traditional components like CD, DVD, and Blu-ray disc players can all be accommodated. Even older analogue sources and turntables can be used with the optional DD Analogue/Phono Module.

    The Direct Digital platform includes a large amount of DSP processing power, and NAD has fully exploited this power with a toolbox full of useful features. Even familiar features, like the volume control, benefit from the Direct Digital platform. Perfect signal tracking and channel balance combined with a total freedom from noise and distortion characterize this remarkable volume control. Traditional bass and treble controls also take on a new usefulness when distortion and phase shift are totally absent.

    An 'electronic crossover' function is also included to easily allow bi-amplification or subwoofer integration. Frequencies from 40Hz to 200Hz can be selected with the high pass signal sent to the C 390DD amplifier section and the low pass sent to the preamp out.

    One of the major problems in any high power music system is what we call 'room modes' or 'standing waves'. The wavelengths in the bass frequencies are so large that room dimensions disturb the even propagation of the sound (think of water ripples in a fish tank – when the wave hits the tank boundary a reverse interference wave is produced). The result of this effect is that certain bass notes are reinforced and become much too loud, making the bass sound 'boomy'. This effect actually changes the perception of the harmonic structure of the bass instruments and spoils the illusion of "listening through" to the acoustic space of the recording. Our simple solution is what we call Room EQ. Playing back a supplied test tone sequence allows this problem to be easily tamed using your ears and the C 390DD Room EQ filters. There are six frequency centres in the low bass region that can be cut (or slightly boosted) to remove the 'boom' without reducing the low bass response. The width or "Q" of the filter can also be adjusted to be wide or narrow to address a number of different room configurations.

  • Idle Power: 40W

    Standby Power: <0.5W

    Unit Dimensions (WxHxD) - Gross* 435 x 132 x 388mm
    17 1/8 x 5 1/4 x 15 5/16 inches**

    Net Weight: 7.7kg (16.94lb)

    Shipping Weight: 9.78kg (21.5lb)