Hafler 9180 - Manual (Page 9)

OUTPUTS
I
All output connections to the amplifier must be performed with the amplifier off!
The left and right audio outputs from the amplifier are via standard 5-way type, 3/4” spacing,
binding posts. Connect these binding posts to the loudspeakers. The amplifier’s binding posts will
accept single or dual banana plugs, spade lugs, pin plugs, or bare wires. If using bare wires, it is
recommended that the ends of the wire be tinned with solder so that no stray strands can cause
a short circuit to the chassis or adjacent terminals.
To ensure proper speaker phasing and frequency response, be sure to connect each respective
amplifier RED (+) terminal to the speaker RED (+) terminal, and the amplifier BLACK (-) terminal
to the speaker BLACK (-) terminal. The polarity symbols (+/-) for Stereo Mode are labelled below
the amplifier’s binding posts.
For operation in the Mono Mode, a single loudspeaker should be connected to the two RED binding
posts only. No connection is made to the amplifier’s BLACK binding posts. Connect the speaker’s
RED (+) terminal to the amplifier’s RED terminal labelled (+), and the speaker’s BLACK (-) terminal
to the amplifier’s RED terminal labelled (-). The polarity symbols (+/-) for the Mono Mode are
labelled above the amplifier’s binding posts.
GAIN
CONTROLS
MONO/
STEREO
SWITCHING
SOFT TURN-
ON/OFF
SYSTEM
THERMAL
PROTECTION
SYSTEM
The 9180/9270 Amplifier is equipped with front panel mounted Gain Controls. These controls may
be used to attenuate the input signal to the amplifier. The maximum clockwise position of these
controls applies the full input signal to the amplifier. Intermediate positions of these controls will
partially attenuate the signal, and the full counter-clockwise position attenuates the input signal
completely.
Most applications will dictate that these controls be set to their maximum clockwise position. In
situations of unusually high level signal sources, or for matching levels in multiple amplifier
installations, it may be desirable to use an intermediate position of the Gain Controls. Unless
intentionally introducing different gain levels in the two channels of the amplifier, these controls
should normally be set at the same rotational position.
In the Mono Mode, the Left Gain Control effects the overall gain of the amplifier. The Right Gain
Control has no effect.
The 9180/9270 Amplifier may be operated in the normal two channel Stereo Mode, or may be
converted (bridged) to a higher power, single channel amplifier in the Mono Mode.
Operation of the Stereo/Mono switch must be performed with the amplifier off! Set the Stereo/
Mono Switch in the OUT position for Stereo Mode, or in the IN position for Mono Mode. Mono Mode
operation requires different input and output connections: consult the sections of the manual titled
“Inputs” and “Outputs”.
The 9180/9270 Amplifier is equipped with a Soft Turn-On/Off System that gradually activates the
amplifier’s circuitry to avoid spurious noises as the power supply stabilizes.
At turn-off, this same system rapidly deactivates the amplifier’s circuitry before the power supply
begins to collapse, again eliminating any spurious noises.
The 9180/9270 Amplifier is equipped with a Thermal Protection System that constantly monitors
the temperature of the heatsinks. When the heatsink temperature reaches a pre-determined level,
the amplifier’s circuitry is electronically shut down through the same system that provides the Soft
Turn-On function. When the heatsinks cool to a safe operating temperature, normal operation of
the amplifier resumes.
-8-
5-way type, 3/4" spacing,