NAD 925, Owner'S Manual, Page: 5 / 28

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About the 925THX
Designed specifically for home theater and cus-
tom installation set-ups, the NAD 925THX Power
Amplifier delivers uncompromising performance. It
combines supreme reliability, flexibility, and perfor-
mance with outstanding value.
Flexibility has always been an important part of NAD
components. Such flexibility is particularly important
in home theater and other multi-channel systems.
That’s because it is common for a multi-channel sys-
tem to incorporate different brands and models of loud-
speakers. Often these speakers have different levels
of efficiency. The individual input level controls for the
five channels of the NAD 925THX make it easy to
compensate for such differences in efficiency, and
achieve the ideal system balance.
Ample dynamic headroom of the 925THX ensures
that the very wide dynamic range of modern cinema
soundtracks and digital music sources will be pre-
served. In addition, the 925THX will handle low im-
pedance speakers with ease.
The 925THX incorporates NAD’s unique Soft-Clip-
ping circuitry in all five channels. Any amplifier can be
overdriven if it is played too loud, exceeding the maxi-
mum output power. Under such circumstances, am-
plifiers 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 out-
bursts in which, unlike music, it is difficult to hear this
potentially damaging distortion. Five status LED’s on
the front panel illuminate when the Soft Clipping cir-
cuit is engaged. Soft Clipping can be defeated with a
rear panel switch.
The design:
The NAD 925THX houses five individual amplifi-
ers, each on separate circuit board. Each amplifier
channel acts as a “mono block” within the chassis.
Each input connector, and set of loudspeaker output
terminals, is directly connected to that channel’s cir-
cuit board. This design eliminates extra wiring and
keeps signal paths short. Furthermore, this modular
design increases reliability and thermal efficiency.
The input circuit uses a totally new dual differential
input topology that operates in true Class-A mode.
The special Holmgren™ toroidal transformer has
less hum and magnetic leakage than conventional
toroidal transformers, but retains the usual benefits
of high efficiency and high power-to-weight ratio.
Ruggedness and reliability are critical in custom-
installed systems. The 925THX uses a combination
of fuses and non-intrusive electronic protection. This
provides highly effective protection that does not ef-
fect audio performance. Each channel is protected
against excess temperature, DC fault and loudspeaker
short-circuit. The 925THX’s inherently conservative,
high-voltage/high-current output stage has been de-
signed for years of trouble-free service.
NAD was the first company to introduce a THX
certified power amplifier. In that tradition, the 925THX
easily passes Lucas Films’ stringent THX performance
requirements. As a result the NAD 925THX will handle
the most demanding signals with ease, and yet pre-
serve every subtle audio detail in the most demand-
ing THX and Dolby Surround systems.
Installation Precautions
WARNING – To reduce the risk of fire or electrical
shock, do not expose the amplifier to rain or moisture.
CAUTION – For units factory-set at 115 volts AC
match the wide blade of the power plug to the wide
slot of the power outlet, to prevent electrical shock.
Be sure the plug is completely inserted into the re-
ceptacle.
Turn off all the components in the system when-
ever connecting or disconnecting any audio signal
wiring. Once all signal connections have been com-
pleted, turn down all the system’s main volume con-
trol before turning the system components on. Then
increase the volume control setting carefully to avoid
damage to the system components.
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