AM CHANNEL
Sensitivity
1.5 microvolts.
Selectivity
Narrow; 4KC bandwidth, ± 10KC from center
down 53db.
Medium 1; 13KC bandwidth, ±10KC from
center down 20db.
Medium 2; 23KC bandwidth, ±10KC from
center down 1.5db.
Broad; 23KC bandwidth, ± 10KC from center
down 1.5db.
These characteristics are substantially un-
changed over entire RF tuning range.
Distortion
Less than 1½% at 100% modulation.
Hum
50db below full signal.
Audio Bandwidth
Narrow; within 3db, 20 to 2,000 cycles.
Medium 1; within 3db, 20 to 6,500 cycles.
Medium 2; within 3db, 20 to 8,000 cycles.
Broad; within 3db, 20 to 11,500 cycles.
10KC Whistle Filter
70db rejection at 10KC; none on Broad
setting.
Output
Approximately 4 volts, low impedance,
Power Consumption
75 watts, 105 to 125 volts, 50 to 60 cycles,
(entire tuner).
Tube Complement (18)
6BA6 AM RF Amplifier
6BE6 AM Converter
6BA6 1st AM IF Amplifier
6BY8 2nd AM IF Amplifier
6BY8 AGC Amplifier
6U8 AM Audio Preamplifier
6BN4A FM RF Amplifier
6BN4A FM Oscillator
12AT7 FM Mixer
(3) 6AU6 FM IF Amplifiers
6BN8 FM Ultrasonic Muting
6AU6 1st FM Limiter
6CS6 2nd FM Limiter
12AU7 FM Meter and AGC Clamp
6U8 FM Audio Preamplifier
6BW4 High Voltage Rectifier
(10mmu to both channels)
Dimensions
Front Panel: 15
5
/
8
inches by 5
1
/
8
inches.
Overall depth of chassis behind front panel:
12
3
/
16
inches.
Depth from face of knobs to face of mount-
ing panel: 1¼ inches.
Weight
Chassis-only, 27 pounds; in shipping carton,
32 pounds.
FRONT PANEL INFORMATION
TUNING DIALS
The MR66 includes AM and FM tuning
dials on the front panel. The AM tuning knob
is at the left and the FM tuning knob is at the
right. The AM tuning dial is calibrated in
kilocycles and the FM tuning dial is calibrated
Figure 1. MR66 Front Panel.
in megacycles. Each tuning dial also includes
a 0-100 logging scale. Tuning back to a
particular station is much easier by keeping
a record of the exact station location on the
logging scale.
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