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