Two pairs of audio output jacks are on the
back panel. One pair of jacks is controlled
only by the front panel volume control. The
other pair of jacks is controlled only by the
back panel output adjust controls. Two stage
feedback type preamplifiers on both chan-
nels provide low impedance outputs. More
than sufficient output volume is available to
feed power amplifiers as well as preamplifiers.
A new type of mechanical tuning assembly
gives the MR65B an extremely smooth fly-
wheel tuning action. The tuning capacitor is
driven directly, and in turn drives the pointer.
Backlash is practically eliminated with this
method of design. A teflon lined pointer
carriage and nylon pulleys reduce friction
and wear to give an unusually smooth and
quiet dial action.
SPECIFICATIONS
Useable Sensitivity
2.5 microvolts at 100% modulation (±75KC
deviation) for less than 3% total noise and
harmonic distortion in accordance with IHFM
standards.
Audio Frequency Response
Within ½db from 20 to 20,000 cycles.
Distortion
Less than 0.5% at 100% modulation ±75KC
deviation.
Capture Ratio
1.5db at 100% modulation.
Muting
IF injected ultrasonic muting: at least 60db
noise reduction between stations.
Oscillator Drift
Less than 25KC with AFC disabled; negligible
with AFC in operation.
Image Rejection
Better than 80db at 90MC; better than 70db
at 105MC.
Hum
Better than 70db below 100% modulation.
Output
Approximately 2.5 volts; low impedance.
Antenna Inputs
300 ohms balanced; 75 ohms unbalanced.
RF Amplifier
Cascode with 6DS4 Nuvistor in first stage.
IF Amplifiers
Four, with 200KC bandwidth, flat top
response
Limiters
Two
Radiation
Substantially below FCC requirements.
Multiplex Channel Separation
Better than 30db at 1000 cycles.
Multiplex Filter
Greater than 48db suppression of 19KC
pilot and 38KC carrier.
Multiplex Indicator
Front panel multiplex stereo light activated
by 19KC carrier-only.
Multiplex Type
Peak-detecting, self-matrixing detector.
Tube and Semiconductor Complement
1—6DS4 Nuvistor, 1st RF.
1—12AT7, 2nd RF and Mixer.
1—6BN4A, Oscillator.
1—6AU6, 1st IF.
1—6AU6, 2nd IF.
1—6AU6, 3rd IF.
1—6AU6, 4th IF and 1st Limiter.
1—6CS6, 2nd Limiter and Muting.
1—6BN8, Muting Amplifier, Muting Detector,
AVC Clamper.
2—6BL8, Left and Right, 1st and 2nd Audio
Amplifiers.
1—12AU7, Balanced Tuning Meter Amplifier.
1—6U8, MPX Amplifier, MPX Indicator Con-
trol.
2
Содержание MR65B
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