McIntosh MR 74, Owner'S Manual, Page: 8 / 20

Back Panel information Front Panel information
TP1 and TP2
Test points TP1 and TP2 are provided for tuner
circuit alignment. They are also used in conjunction
with the Mclntosh Maximum Performance Indicator.
120 AC POWER OUTLET
Provides 120 volt AC power up to 400 watts for
additional equipment such as amplifiers, or other
equipment. This outlet is not fused. It turns on and
off with the front panel AC power switch on the
VOLUME control.
AC POWER CORD
Connect the AC power cord to a 120 volt, 50 to 60
Hz power line receptable. The power used by the
MR 74 is 30 watts.
FUSE
A 0.5 AMP SLO-BLO fuse protects the tuner cir-
cuits. This fuse does not protect additional equip-
ment connected to the back panel AC power outlet.
AM ANT SWITCH
Adjust the MR 74 AM ANT switch to match the par-
ticular type of AM antenna used. EXT position is
used for an outdoor antenna. LOOP position is for
the built-in ferrite loopstick.
ANTENNA CONNECTION STRIP
Provides easy push type connectors for an AM
antenna, a ground connection, and a 300 ohm FM
antenna.
FM ANTENNA — 75 OHM
Provides a type F male connector for a 75 ohm
unbalanced FM antenna.
AUDIO OUTPUTS
The FIXED OUTPUT pair of AUDIO OUTPUT jacks
provides audio signals unaffected by the MR 74
front panel VOLUME control. Use these output jacks
to connect the tuner to a stereo preamplifier or other
equipment which has its own master volume control.
The FRONT PANEL CONTROLLED pair of AUDIO
OUTPUT jacks provides audio signal controlled by
the MR 74 front panel VOLUME control. Use these
output jacks to connect to external power amplifier,
tape recorders, or any equipment which requires
front panel control of tuner output volume.
TUNING DIAL
The MR 74 has three dial scales:
1. AM — Marked 55 to 160
2. FM — Marked 88 to 108
3. Logging scale — Marked 0 to 100
The logging scale can be used to accurately re-
tune any station. You may find it easier to keep a
record of your favorite stations by use of the logging
scale.
A small portion of dial pointer has been illuminated
to increase the ease of tuning.
INDICATORS
The MR 74 has four indicators on the dial panel:
STEREO indicator, MULTIPATH indicator, SIGNAL
STRENGTH meter, and the FM TUNING meter.
STEREO INDICATOR
The STEREO indicator lights red when the dial
pointer is tuned to or corsses a station broadcasting
the 19,000 Hz carrier for stereo. The special circuit
used will light only when the 19,000 Hz multiplex
carrier is present in the signal. The indicator will not
light on noise pulses or interference.
MULTIPATH INDICATOR
The MULTIPATH indicator is an exclusive Mc-
lntosh development.
The proper use of the MULTIPATH indicator
makes it possible to improve FM reception with
FM antenna positioning.
An electron ray indicator is used to show multi-
path reception. When rotating the antenna, observa-
tion of the multipath indicator will show best orien-
tation for the FM station being received. Multipath
distortion causes the two beams on the indicator to
fluctuate rapidly. When the antenna is rotated to the
best position, the indicator beams tend to remain
steady. The directional antenna then picks up the
desired signal and rejects the reflected multipath
signals. In some locations it is possible for the best
reception to occur when the antenna picks up a
strong reflected signal rather than the direct signal.
Multipath distortion is practically independent of sig-
nal strength.
SIGNAL STRENGTH METER
The SIGNAL STRENGTH meter indicates the
strength of the signal as received from the antenna.
The higher the indication, the stronger is the signal,
FM TUNING METER
An FM station is correctly tuned when the meter
needle is in the black area of the FM TUNING meter.
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