| NAD T773 Receiver |
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| Friday, 01 October 2004 | |
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Introduction When
it comes to designing and manufacturing components with excellent QRP
(quality to price ratio), few companies can match the track record of
NAD. For the last three decades, NAD has stayed true to their founding
creed, designing and manufacturing components with outstanding
performance, excellent value and simplicity of operation. Speaking as a
satisfied customer, I’ve owned many NAD products through the years,
utilizing them in a broad array of applications with excellent results.
NAD has applied this same high-performance, cost-conscious design and
manufacturing philosophy to their first seven-channel, surround sound
receiver, the T 773. Positioned at the top of NAD’s “Classic” line of
audio/video receivers, the T 773 incorporates an extremely
full-featured, flexible processor/preamplifier/tuner section with a
formidable multi-channel amplifier. Offering the latest surround sound
DSP algorithms, with a few proprietary modes as well, the T 773 is also
capable of being upgraded via a RS232 port, insuring its ability to
stay current with potential future upgrades and technological advances.
In fact, just after the completion of my review, NAD offered an upgrade
to their Operating System (OS), now identified as Version 2.0. This
latest OS improvement includes an assortment of operational and set-up
features, along with the addition of two new surround formats, Dolby
Digital Pro Logic IIx and Dolby Pro Logic IIx. Quite reasonably priced,
the NAD T 773 is currently shipping with the Version 2.0 OS and the
cost remains unchanged at a suggested manufacturer’s retail price of
$1,799.
DescriptionAesthetically, this T 773 looks relatively similar to many NAD receivers from the last 20 years, hence the “Classic” series nomenclature. With its muted charcoal gray casing and minimalist graphics, the T 773 is neutral and unassuming in its appearance. Weighing in at a relatively husky 52.8 pounds, the T 773’s overall physical dimensions are well proportioned, measuring 17-1/8 inches wide, by seven-and-five-eighths inches high, with an unconnected depth of 16-5/8 inches. Admittedly, I love the look of high-tech, modernistic components, and the T 773 is not likely to win many “eye candy” awards. Still, I applaud NAD’s refusal to stray from their heredity, shrugging off costly and unnecessary cosmetics, and continuing to offer high-performance components at exceptionally competitive prices. Potential buyers should not be taken aback by this, as it falls directly in line with the NAD philosophy of spending money where it truly makes an appreciable sonic difference. NAD uses high-quality 192 kHz/24 bit DACs and operational amplifiers that are selected on the merit of their musical sound quality. Particular attention is given to the front main channels, which are fed from a specially selected two-channel DAC for the best possible sonic performance with Redbook CDs and uncompressed PCM recordings. As with most NAD components, the front panel is uncluttered and arranged in a straightforward, sequential manner. Screening of the receiver’s modes, settings and functions for both main system and second zone can be viewed through the Vacuum Fluorescent Display (VFD), located at the top right center of the unit. To the right of the VFD is a stable, velvety smooth volume control, which is adjustable in one-decibel increments. A lighted power switch is positioned at the top left side of the front panel. Directly to the left of the VFL are four buttons and two toggle controls managing the displays status and tuner section. Easy front access is available to both audio and video inputs (left and right audio, composite and S-Video), along with a headphone jack that is hidden behind a small removable cover towards the bottom left. The remaining controls are centered on the front panel and include buttons for speaker selectors, independent video and audio source selectors, the tape monitor loop and a digital audio selector, which is independent from any video switching. Furthermore, there is a control for direct access to the 7.1 analog inputs, a surround mode switch, a button that enables level adjustments for each loudspeaker individually, and tone controls with a defeat position. The NAD has an abundance of audio, video and control connections, including six sets of audio and video inputs, each with S-Video and Composite, two for the inputs can be paired with matching audio and video outputs to create full tape loops. Component Video is handled by three sets of inputs and one output. NAD incorporated six user-assignable digital inputs (four coaxial, two TOS link), two digital outputs (one coaxial, one TOS link) to manage direct digital sources. Creating a virtually transparent path for SACD and DVD-Audio sources, the 7.1 input has only the main volume control and an output buffer stage in the circuit. To maintain purity, the analog stereo inputs are not digitized unless a surround mode is engaged. A second zone Multi-Source audio/video preamp output is offered, complete with independent source and volume control. Also, there is an A/ B speaker switcher (two-channel only), direct preamp outputs for connecting an external amplifier, an audio only tape loop, two subwoofer outputs, along with a multitude of additional connections to accommodate most complex switching and custom installation needs. As a full-featured surround sound receiver, the T 773 incorporates all of the present processing modes such as Dolby Digital, Dolby Digital EX, DTS, DTS EX Matrix, DTS ES 6.1, Dolby Pro Logic, a fully adjustable Dolby Pro Logic II and DTS NEO:6. As mentioned earlier, NAD’s most recent upgrades incorporate two new modes, Dolby Digital Pro Logic IIx and Dolby Pro Logic IIx (absent from my review sample). Both algorithms process stereo and 5.1 signals into a 6.1- or 7.1- channel output. Users can choose Movie or Music modes to tailor their listening experience to the source material. For two-channel signals, Dolby Pro Logic IIx Music mode features three additional user controls: Dimension, Center Width and Panorama. Dolby Digital Surround EX is also now selectable from the front panel or the remote. Additionally, the T 773 provides other enhanced multi-channel stereo modes, such as NAD’s own Enhanced Ambience Recovery System (EARS), a proprietary stereo to 5.1 channel algorithm, and Matrix 7.1 (another proprietary stereo to 7.1 algorithm). For non-critical listening, a Stereo Enhanced mode can be selected, sending unprocessed full-range stereo to selected channels, a useful feature for background music or party situations. Included in the T 773 is an RDS FM/AM tuner section, featuring 30 station presets. Each preset can be stored with a custom name, or can automatically scroll station ID and text messages from RDS enabled FM stations. Direct access is available from the remote to either presets or station frequency. Performance-wise, the T 773 is a very potent receiver, rated at 110 watts per channel, from 20Hz-20 kHz at less than 0.08 percent total harmonic distortion with all seven channels driven simultaneously. Slightly greater power (145 watts) is available for two-channel operation. Great attention was paid to overall layout and grounding design in order to achieve the lowest possible distortion, while retaining the ability to pass exceptionally high peak currents. The power supply uses NAD’s exclusive PowerDrive circuit to extract maximum performance under varying conditions and is, in essence, an advancement of NAD’s Power Envelope concept, which was introduced during the 1980s. This “smart” circuit offers a unique combination of very low distortion, even when driving difficult low impedance speakers, and helps sustain high dynamic power and peak current for accurate musical dynamics. The T 773’s power amplifier section uses an all-discrete design with multiple high-current output devices in a Class AB configuration. Output power is provided by two Holmgren toroidal transformers, one dedicated to the left, center and right main channels, the other covering the remaining four surround channels. Each transformer has two secondary windings to provide separate high-current and high-voltage power supplies. NADs PowerDrive control circuit is, in effect, an analog computer that constantly monitors voltage, current and temperature to determine the optimum power supply setting, switching between high-voltage and high-current settings based on actual conditions. The T 773 also uses NAD’s proprietary Soft Clipping circuitry (which can be disabled via an external switch), helping to reduce the typical distortion that can be produced when an amplifier is driven beyond its (useful) limits. Cooling is handled via an internal heat sink, which is augmented with five internal precision fans that run at low speeds. This helps to insure that the T 773 can handle any possible ambient temperature, speaker load and dynamic program material without overheating. |
