STEREO TUNER MR66 INTRODUCTION 1 TECHNICAL DESCRIPTION 1 FRONT PANEL INFORMATION 3 BACK PANEL INFORMATION 5 INSTALLATION CONNECTING Monophonic FM and AM Stereophonic FM and AM Stereophonic FM Multiplex Remote Amplifiers Off-The-Air Tape Recording Antenna Connections TABLE OF CONTENTS OPERATING INSTRUCTIONS Monophonic AM Reception Monophonic FM Reception Stereophonic FM-AM Reception Stereophonic FM Multiplex Reception ADJUSTMENTS Muting Threshold AM Signal Strength Indicator FM Tuning Meter AM and
MR66 STEREOPHONIC TUNER INTRODUCTION The Mclntosh MR66 is a precision engineered, sensitive AM-FM stereo tuner. It offers the finest possible reception of AM and FM broadcasts. Every desirable feature is included on the MR66. It is perfect for use in a stereo system where nothing less than THE BEST will do. Once you have used the MR66 and enjoyed its outstanding performance, you will understand why Mclntosh products have earned their reputation as THE BEST. The MR66 is quite flexible in operation.
AM SECTION The MR66 delivers AM reception of the highest possible quality. Four different AM bandwidth/frequency response settings are available. The NARROW setting provides excellent selectivity and high noise rejection for the weaker and more distant stations. The MEDIUM 1, MEDIUM 2 and BROAD settings provide progressively wider frequency response for receiving the closer more powerful stations.
AM CHANNEL Power Consumption 75 watts, 105 to 125 volts, 50 to 60 cycles, (entire tuner). 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 unchanged over entire RF tuning range. Distortion Less than 1½% at 100% modulation. Hum 50db below full signal.
TUNING METERS Two tuning meters are included in the dial panel. At the left is the AM SIGNAL STRENGTH tuning meter. At the right is the FM TUNING meter. An AM station is correctly tuned when the AM signal strength meter pointer indicates maximum right-hand deflection. The actual amount of meter pointer deflection indicates the relative signal strength of each particular station. Strong local stations will cause almost full meter deflection.
close to a much stronger station, a lower AFC setting is usually necessary for best tuning. FM FUNCTION SWITCH Figure 4. Auto Freq Control. nates the possibility of the tuner drifting off the station. The AFC circuit in the MR66 includes an Electronic Delay which is an exclusive Mclntosh development. As the tuning dial is moved, the AFC circuit is temporarily cut off. Approximately three seconds after the dial pointer has come to rest on a particular station, the AFC action gradually comes into operation.
ANT LOOP SWITCH Adjusts the MR66 circuit to match the particular type of AM antenna used. ANT position is for a conventional antenna, usually of the outdoor type, from 50 to 150 feet in length. LOOP position is for the short loop antenna supplied with the MR66. LAMPS SWITCH Provides bright (HI) or dim (LO) front panel lighting. AC OUTLET Provides 117 volt AC power up to 350 watts maximum for additional equipment such as turntables or other tuners.
CUTTING THE FRONT PANEL The PANEL CUTOUT TEMPLATE supplied with your tuner is a full size layout of the front panel cutout and mounting holes. The template is positioned accurately on the cabinet front panel by drilling two locating holes through from the backside of the panel. All measurements for panel cutout location are made on the backside of the panel.
The edge of the strip with the clips must face toward the panel opening. Line up the mounting strips on each side of the panel cutout so the holes in the strips are in line with the holes in the panel. (See Figure 8.) Install the proper length flat head screws through the front panel and into the center hole of each strip. Drive the screws in so the flat heads are flush with the panel. If necessary, countersink the two center holes. ness or less.
directly to a power amplifier if desired. Since the MR66 does not include a front panel volume control, all volume adjustments must be made at the preamplifier. The MR66 rear panel output level controls provide means for setting and balancing the volume levels of the AM and FM outputs. AM monophonic and FM monophonic programs appear at both STEREO MON 1 and 2 jacks, depending on whether the MODE SELECTOR switch is set to MON AM or MON FM.
The AM loop may be conveniently tacked behind the stereo equipment cabinet, or stretched along the floor or baseboard. The loop should be spaced as wide apart as possible. 3 0 0 OHM INDOOR DIPOLE FM ANTENNA AM OUTDOOR ANTENNA Figure 13. Connection For 300 Ohm Indoor Dipole FM Antenna. Figure 12. AM Outdoor Antenna. For best long distance AM reception, use a copper antenna wire 50 to 150 feet in length. Suspend the wire in a straight line as high as possible.
Connect the two wires of the 300 ohm lead-in from the external antenna to the MR66 back panel FM ANT terminals. FROM VHF TV ANTENNA 75 OHM ANTENNA Figure 15. Connection For 75 Ohm Coaxial Antenna. TO TV SET An unbalanced 75 ohm FM antenna may also be used with the MR66. Connect the center lead of the coaxial lead-in cable to the right hand FM ANT terminal. Connect the shield of the coaxial cable to the ground screw next to the right of this same FM ANT terminal. Figure 16. VHF TV Antenna Connections.
caused by a station so weak or distant that it does not over-ride the background noise. With ultrasonic muting in operation a noisy station of this type is automatically rejected. To hear these weaker or distant stations, turn the FM FUNCTION switch to MUTE OUT. Usually the listening quality of a station of this type will be rather poor due to the weak signal and background noise. (See section titled "MUTING ADJUSTMENTS.
panel end cap) until the meter pointer is centered on the zero scale marking.(Tuner Serial Nos. 1N001 to 1N961 have recessed screwdriver-adjust AM meter control near back of tuner chassis.) In areas where noise or interference is high, the meter may move above the zero position when the AM antenna is reconnected to the back panel terminals. This is normal and does not affect the meter operation. FM TUNING METER Turn the FM FUNCTION switch to FM OUT position.
Your Mclntosh MR66 tuner will give you many years of pleasant and satisfactory performance. If you have any questions concerning the operation or maintenance of this tuner, please contact CUSTOMER SERVICE McINTOSH LABORATORY INC. 2 CHAMBERS STREET BINGHAMTON, NEW YORK Our telephone number is 723-5491. The direct dial area code is 607. GUARANTEE Mclntosh Laboratory, Inc. guarantees this equipment to perform as advertised.
AM STATION LOG STATION DIAL FREQ.
FM STATION LOG STATION DIAL FREQ.
LABORATORY INC. 2 C H A M B E R S STREET, B I N G H A M T O N , N. Y. M a d e in U.S.A. Phone — A r e a Code 607-723-5491 1M-AA107-236 Printed in U.S.A.
