GBNAD 912 POWER AMPLIFIER
A NOTE ON INSTALLATION 3. LINE OUTPUTS
Each input has an accompanying line output which
This unit may be installed on any sturdy, level sur-will pass the signal on to another amplifier input or
face. Since its power transformer generates a mag-
netic hum field of moderate strength, a turntableother line-level device. The line outputs are buffered,
so that a low impedance or short circuit placed across
(especially one with a moving-coil pickup cartridge)
should not be located near the amplifier.it will not affect the signal at the input. If the 912 is
being used to amplify a remote pair of speakers, con-
The amplifier requires ventilation. Do not obstructnect the systemOs preamplifier to the 912Os inputs,
the air outlet grilles on the top or bottom covers, and
then run a pair of cables from the 912Os outputs to the
do not place the amplifier on a rug or other soft sur-inputs of the main stereo amplifier. (See Diagram #1).
face. Do not place the amplifier in an enclosed situa-
tion such as in a bookcase or in a cabinet.
SAFETY WARNING: Please ensure that the4. INPUT LEVEL
Volume controls at the rear of this amplifier are set toThe amplifier is equipped with separate input level
controls for each channel. Before turning on the 912
minimum level (i.e. COUNTER CLOCKWISE, viewed
from the back panel).for the first time, make sure all level controls are in
their normal minimum (full-clockwise) power posi-
If this piece of equipment is to be used in a multi-tion. Under some circumstances, other settings may
room ouput of a NAD product, please ensure that
be useful for:
before turning on the system for the first time, the
Volume controls on any auxiliary amplifier ARE SET(1). Level-matching. In a surround-sound or other
TO THE MINIMUM LEVEL.multi-amplifier system, reduce some of the controls
as necessary to balance the system with speakers of
The multi-room output is not affected by the
Volume or Tone controls (Treble, Bass) of the mainvarying sensitivities.
(2). Extended volume-control range. Many stereo
system controls, so care must be taken to prevent
auxiliary amplifiers being driven at full output level.systems have so much voltage gain that the speakers
(or your ears) are over-driven at any volume-control
WARNING TO UK USERS. If this appartus is notsetting higher than 11 or 12 oOclock. As a result you
fitted with a UK three-pin plug, do not attempt to
insert the attached plug into a UK mains socket.are confined to using only the lower half of the vol-
ume controlOs range, where adjustments are impre-
Instead, cut the plug from the mains lead and attach
a fused UK three-pin plug using the following safetycise and where channel-balance errors tend to be
greater. If all input-level controls are reduced, you
advice on wiring.can turn up your preamplifierOs volume control, mak-
IMPORTANT. The wires in this mains lead are
ing effective use of most of its range. (Suggestion:
coloured BLUE and BROWN;adjust the input level controls so that your preferred
BLUE: NEUTRALBROWN: LIVEmaximum sound levels usually occur at about 2 or 3
The colours of these mains lead wires may not cor-oOclock on the volume control.)
respond with the coloured markings identifying theAs an added benefit, this procedure suppresses
terminals in your plug. In this case the BROWN wireany noise produced by the preampOs high-level cir-
must be connected to the terminal which is markedcuitry (e.g. any residual hum or hiss that does not go
L(ive) or coloured RED. The BLUE wire must be con-away when the Volume is turned down).
nected to the terminal marked N(eutral) or coloured(3) Balance correction. Small errors in channel
BLACK. No connection should be made to the termi-balance can dramatically degrade the apparent
nal marked E or coloured green or green and yellow Odepth� and Oair� of the stereo image. Such balance
errors may be due to normal production-line differ-
ences in speaker sensitivity, differences in the
acoustic environment around the two speakers, and
slightly different distances from your chair to each
REAR PANEL CONNECTIONS speaker. You can use the input-level controls to cor-
rect these fixed balance errors, freeing your preampli-
1. AC LINE CORD fierOs balance control to correct balance errors in
Plug the AC line cord into a nearby wall outlet that
provides the correct AC power line voltage, or into arecordings.
switched convenience outlet on your preamp.Switch the preamp to mono and sit in your normal
listening location. Ideally the Ophantom� central
image should seem to be floating in mid-air midway
2. INPUTSbetween the left and right speakers. If it is located
The 912 has both inputs and outputs. Before mak-off-center, closer to one speaker, turn down the input-
ing connections to the amplifier, make sure thelevel control for that channel slightly in order to re-
POWER is switched OFF. center the phantom mono image. Then restore the
Connect the signal cable from the preamplifier, sur-preamp to normal stereo operation.
round decoder or other signal source to the inputs. If
you want to use the 912 as a single 90-watt amplifier
instead of a stereo 30 W/ch amp, see BRIDGING5. SPEAKER CONNECTIONS
This amplifier is equipped with special high-current
(Refer to item 6). binding-post speaker terminals to handle the highest
peak power levels that may occur in the Obridged�
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ACEC
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