NAD T955 User manual

Separates vs. All-in-one receivers
NAD designs and sells both receivers and separates, and each can provide a spine tingling Home Theater
experience. While receivers offer a simple one-box solution to the switching, decoding, and amplification
needs of the Home Theater, there are some inherent limitations to combining high power amplifiers with
sensitive switching and decoding circuits. The high current circuits required for the highest levels of audio
performance create a lot of heat and stray magnetic fields that limit the ability of low level audio and video
circuits from achieving optimum levels of low noise and distortion. This is a fact of life dictated by the laws
of physics.
The 5-Channel NAD T955 is a perfect accompaniment to the T175 A/V Tuner Preamplifier.
We also believe that there is a practical limit to the size of a component developed for home use, a limit that
is often surpassed in the largest and most expensive AV receivers.
Another consideration is cost. While a receiver may appear to offer more for your money in the short run,
the fact of the matter is that receivers quickly become obsolete. This is because decoder technology is
still evolving very fast. If you want the latest in video performance and surround sound decoding, plan on
replacing your decoder every 3–5 years. The decoder is but one part of the receiver, yet it is inseparable,
requiring the replacement of the entire unit even though only one part is obsolete. But amplifier technology
is very mature and the performance of the T955 amplifier will not be exceeded in the foreseeable future.
After all, we still have NAD customers raving about the sound of their NAD amplifiers nearly 30 years
later! With an AV receiver the baby goes out with the bath water when upgrading the digital processor to
accommodate the latest surround sound decoding format, as there is often no way to reuse the amplifier
section.
Massive power
Many people are under the illusion that the only reason for high power is to play loud. In fact, the primary
advantage to high power is the ability to play loud and clear. When the distortion is very low, the sound isn’t
loud, it’s BIG! Distortion is what makes sound ‘loud’, and this can lead to listener fatigue – that feeling that
it is just too loud. Big sound is effortless and compelling, drawing the listener into the performance and
T 955 Five Channel Power Amplifier
• 5 x 100W Simultaneous Full Disclosure Power
• 5 x 160W Minimum Continuous Power (FTC)
• Dynamic power - 150W 8 Ohms, 200W 4 Ohms, 260W 2 Ohms
• PowerDrive™ amplifier technology
• Custom wound Holmgren Toroidal transformer with proprietary
shielding to eliminate EMF leakage
• Custom 5-Way Binding Posts
• 12V Trigger for advanced control options
• NAD Soft Clipping™
• Detachable AC cord
Features
Details

immersing you in the musical or cinematic moment.
Unlike most surround sound receivers (NAD’s own receivers are a
rare exception) that only rate power with 1 or 2 channels running,
or use very short term measurements, the T955 can deliver its
full rated power continuously for long periods of time. And dynamic
power, the power that more closely represents the true nature of
musical signals, is nothing short of sensational.
Sophisticated circuitry
The T955 is comprised if 5 individual ‘Mono-block’ amplifier
channels. Based on NAD’s proven all discrete circuit topology
as used in the award winning C352 and C372 stereo amplifiers,
this design offers very low distortion combined with extremely
high current capability. Active current sources and common
base current followers in the power amp section combine to
improve supply rejection to unprecedented levels, well beyond the
audible frequency range. This has the effect of reducing dynamic
intermodulation distortion between music signal components in
different frequency ranges, and between these signals and supply
ripple and distortion components. In measurement terms static
and dynamic IM distortion are reduced by between 10dB to 20dB.
(to between -90dB and - 100dB.) compared to conventional
designs.
In audible terms this improves definition, purity and resolution,
hence imaging. And yes, imaging is very important in an amplifier
designed for surround sound listening. Sure, any surround
sound component will surround you with sound, but the best
surround sound components have the effect of transforming your
listening room into the sound stage of the musical or cinematic
performance.
NAD’s PowerDrive™ circuitry is a big part of this performance
story. By measuring each channel’s dynamic impedance individually
and computing the optimum power supply voltage required to drive
the output stage for maximum power and efficiency. PowerDrive
permits high dynamic power and low impedance drive capability,
while maintaining ultra low (<0.03%) levels of distortion.
Each channel has individual over current, DC, infrasonic and
ultrasonic overload sensing and protection for complete reliability
under even the most severe operating conditions.
Custom designed heat sinks keep things cool under the most
severe operating conditions without the requirement of forced air
cooling and its potential noise. A massive Holmgren toroidal power
transformer insures excellent voltage regulation under the most
demanding conditions, and offers high efficiency and a low stray
magnetic field to help keep distortion at vanishingly low levels.
NAD Electronics International reserves the right to change specications or features without notice. NAD is a registered trademark of NAD Electronics
International. All rights reserved. No part of this publication may be reproduced, stored, or transmitted in any form whatsoever without the written
permission of NAD Electronics International. © 08/07 NAD Electronics International.
www.NADelectronics.com
© NAD T955
Serial No./No. De Series
+12V TRIGGER IN
AUTO TRIGGER
ON
ON
OFF
OFF
SOFT
CLIPPING
INPUT
SPEAKER
INPUT
SPEAKER
INPUT
SPEAKER
INPUT
SPEAKER
INPUT
SPEAKER
CHANNEL 5
FRONT R
CHANNEL 5
FRONT R
CHANNEL 4 CHANNEL 3 CHANNEL 2
CHANNEL 4
CHANNEL 3
CHANNEL 2 SURR R
CENTER
SURR L
SURR R CENTER SURR L CHANNEL 1
CHANNEL 1
FRONT L
FRONT L
SPECIFICATIONS
Simultaneous Full Disclosure Power
(4/8 Ohms, 20Hz - 20kHz, at rated distortion)
Minimum Continuous Power (FTC)
Rated Distortion (THD 20Hz-20kHz)
Peak Undistorted Current
IHF dynamic power at 8 Ohms
IHF dynamic power at 4 Ohms
IHF dynamic power at 2 Ohms
Damping Factor
Input Impedance/Capacitance
Input Sensitivity
5 x 100W (20dBW)
5 x 160W (22dBW)
0.03%
>80 Amps @0.1 Ohm
150W (21.8dBW)
200W (23dBW)
260W (24.1dBW)
8 Ohms >100 20Hz - 20kHz
20,000 Ohms/380pf
1.0V
Voltage Gain
Frequency Response
Signal/Noise Ratio
Net Dimensions (W x H x D)
Gross Dimensions (W x H xD)*
Net Weight
Shipping Weight
29.0dB
20Hz - 20kHz +0, -0.2dB
2Hz - 100kHz -3dB
1 watt 8 Ohms >100db IHFA
100 watts > 130db IHFA
17 1/8 x 6 1/8 x 15 7/8”
(435 x 155 x 403mm)
17 1/8 x 6 5/8 x 16 7/8”
(435 x 175 x 429mm)
45 lbs (20kg)
49 lbs (22kg)
* Gross dimensions include: Volume knob / speaker terminals / connectors / feet.
Note: Installers should allow a minimum clearance of 2-4 inches for wire management.