McIntosh MR 73 Owner's Manual page 13

STEREO FILTER
The STEREO FILTER reduces noise on weak stereo stations.
Turn the switch to the IN position on noisy stereo stations.
FM MUTING
Muting suppresses the background noise and hiss normally heard
between stations. Turn the control to the IN position for muting.
Weak stations that may not override noise and interference are also
suppressed by the muting.
In the OUT position, the muting is turned off. This allows conven-
tional FM tuning with the noise and interference present. Use this
position to tune weak or noisy stations.
VOLUME
This control adjusts the output volume level of the tuner at the
back panel AUDIO OUTPUT jacks marked FRONT PANEL CON-
TROLLED. The other pair of jacks is marked FIXED OUTPUT. They
are not affected by the volume control. Full tuner output is always
present at the FIXED OUTPUT jacks.
The VOLUME control has been precision tracked throughout the
listening range (0 to —65dB) for accurate stereo balance.
AC ON/OFF
The AC switch is part of the VOLUME control. Turning the VOL-
UME control totally counterclockwise turns the AC to the MR 73
OFF.
PANLOC BUTTONS
At the bottom of the front corners are the PANLOC buttons. After
a tuner is installed on the PANLOC shelf, depressing the PANLOC
buttons will lock the tuner firmly in position. Depressing the PAN-
LOC buttons a second time (as with a ball-point pen) will release the
tuner. The tuner can then be slid forward to the inspection and
adjustment position. The PANLOC system gives you absolute ease
of installation, operation and maintenance.
SECONDARY CONTROLS
On the top of the chassis behind the front panel are three sec-
ondary controls. They are MUTING adjust, AM SENSITIVITY, and
DIAL SCALE INTENSITY.
MUTING
The MR 73 ultrasonic muting circuit suppresses all noise between
stations. It suppresses all weaker stations not strong enough to
override the background noise.
The muting threshold setting determines the strength of the signal
which can be heard with muting in operation. The muting threshold
is carefully adjusted to optimum at the factory using precision test
instruments.
If it is found necessary to adjust the muting threshold, turn the
MUTING ADJ to the RIGHT (clockwise) to lower the muting thresh-
old. This allows weaker noisier stations to be heard at the MUTING
IN setting. Turn the control to the left (counterclockwise) to raise the
muting threshold. This allows only the more powerful stations to be
heard at the MUTING IN setting.
AM SENSITIVITY
When the AM SENSITIVITY switch is in the LOW position the
noise between stations is reduced. The RF gain is not as great in the
low position.
DIAL SCALE INTENSITY
Adjust the brightness of the dial panel lights by means of this
switch on the tuner back panel. Set the switch to BRIGHT for
maximum panel light. Set the switch to DIM for less dial light and
extended lamp life.
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