Seven Channel Power Amp: The power rating of 140 watts
(continuous) x 7 is taken with all channels driven simultaneously into a 4Ω or
8Ω load, from 20Hz to 20kHz, at the rated distortion of 0.03% THD. The T 977
provides a dynamic power of 230W/ch into 8Ω and 390W/ch into 4Ω.
NAD's Full Disclosure Power Ratings: NAD uses Full
Disclosure Power (FDP), the most demanding criterion for performance
measurement. FDP specifies distortion under the most extreme conditions of low
impedance loads and frequency extremes, rather than the simple and easy 1kHz @ 8
ohms test quoted by many of other manufactures. NAD uses this stricter
performance criterion because it more closely matches the demands of real music
and real loudspeakers. Maintaining specified distortion at 4/8Ω and at 20-20kHz
is a much more difficult achievement. The benefit of NAD's Full Disclosure Power
is the total elimination of audible distortion at any listening level. This
provides pinpoint imaging and realism with music and movies alike.
Mono-Block Modular Construction: The T 977 employs
mono-block construction for each of its seven channels. Every element of each
channel's circuitry, save the power supply, is fully independent thus
eliminating inter-channel influences as a concern. The T 977 employs active
ground isolation to further eliminate any possibility of inter-channel
interference even when more than one preamplifier is driving the power amp (as
might be the case in a custom installation).
MOSFET Class A Input: The T 977 features a MOSFET
Class A input and driver stage circuits, and a high-current output-stage design,
employing high speed, discrete output devices to promote superb dynamic quality.
PowerDrive Amplifier Technology: The T 977 uses NAD's
proprietary PowerDrive amplifier technology that provides high dynamic power and
low impedance drive capability. By adding a second high-voltage rail to the
amp's well regulated high-current power supply, the amplifier can nearly double
its continuous power on a short term dynamic power basis. This uniquely
efficient power supply topology provides the real world benefits of high dynamic
power that remains uncompromised by low impedance speakers. The PowerDrive
topology allows the T 977 to deliver maximum performance under virtually any
circumstance, independent of the loudspeakers it is driving. The circuitry
automatically senses the impedance characteristics of the loudspeaker and will
then adjust its power supply settings to best cope with that specific load.
PowerDrive topology is a practical approach to enable an amplifier to easily
deal with musical dynamics and difficult speaker loads. PowerDrive not only
makes NAD amplifiers sound better, it makes them cooler running, with improved
efficiency, leading to greater reliability as well.
NAD Soft Clipping: The T 977 incorporates NAD's unique
Soft-Clipping circuitry in all seven channels. Any amplifier can be overdriven
if it is played too loud, exceeding the maximum output power. Under such
circumstances, amplifiers produce extreme high levels of distortion which,
besides sounding very unpleasant, can damage your loudspeakers. The Soft
Clipping circuit suppresses such distortion and minimizes the risk of damage to
speakers. This is particularly important with movie soundtracks which often
contain very dynamic outbursts in which, unlike music, it is difficult to hear
this potentially damaging distortion. The Soft Clipping LED on the front panel
illuminates when the Soft Clipping circuit is engaged. Soft Clipping can be
defeated with a rear panel switch.
Low Loss, Massive Holmgren Toroidal Mains Transformer: The T
977 employs a "Holmgren" transformer for its superior regulation and low stray
magnetic field. This exclusive transformer uses a special core design and
materials to enhance efficiency and make the transformer less sensitive to DC
offsets on the AC mains voltage. Over 80,000 uF of storage capacitance ensure an
ample reserve of power for even the most demanding music and film soundtracks.
Thermostatically Controlled Fan w/ Signal Tracking Circuit:
The T 977 uses a unique variable speed fan cooling system first introduced on
NAD's M25 Masters Series amplifier, allowing the T 977 to deliver massive
amounts of power for hours on end. Many lesser amps thermally protect and cycle
on and off when asked to perform at their maximum causing an unpleasant
disruption of the movie. While a well designed forced air system can eliminate
thermal cycling, it is crucial to keep the noise of the cooling fan from
intruding; especially during quiet passages of the movie or music. To this end,
we have developed a unique circuit that measures not only the operating
temperature but also the level of the input signal, automatically silencing the
fans during quiet passages.
Protection Circuits: This amplifier utilizes a combination
of fuse and electronic nonintrusive protection; dependable, fail-safe, and
sonically benign. Each channel is fully protected against excess temperature, DC
fault, and loudspeaker short-circuit.
Input Gain Control For Each Individual Channel: Each of the
T 977's channels has a single RCA input and individual gain adjustment to
promote easy, accurate system configuration.
Binding Posts: This multi-channel amplifier delivers its
output via heavy-duty "5-way" binding-post speaker terminals.
+12V Trigger Input: The T 977 can be turned on automatically
using the 3.5mm +12 volt trigger input on the rear-panel.