McIntosh MR 71 Owners Manual

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THANK YOU Judging from the stereo equipment you own, you rank high among discriminating music listeners. You are probably no freshman when it comes to stereo. Never-the-less we ask you to read and carefully follow these instructions to insure a successful partnership between you and your new stereo equipment. You now have "THE BEST." Used properly you are in for thousands of hours of musical enjoyment. If you are in a hurry, read page 3 first. This gives you a brief outline of what each control and indicator does. Reading time for this manual is 30 minutes. This is time well spent. MR 71 FM STEREO TUNER INTRODUCTION The Mclntosh MR 71 is a precision engi- neered, highly sensitive FM Multiplex Tuner. The research staff of Mclntosh Laboratory has developed five new tuner circuit improve- ments for the MR 71. 1. Automatic stereo-mono switching that is "clickless" and completely electronic. (Patent applied for.) 2. Multipath indicator to eliminate multi- path reception by showing when your anten- na is rotated to the correct position for mini- mum multipath distortion. 3. Double tuned input circuits before the first R.F. amplifier to reduce spurious re- sponses. 4. New D'Arsonval movement meters of increased sensitivity which do not need zero setting adjustments. 5. A new computer designed filter to re- duce noise from stations broadcasting sub- carrier auxiliary music services. No other tuner uses such a filter. The MR 71 also uses the exclusive Mc- lntosh PANLOC method of installation. The PANLOC system gives you absolute ease of installation, operation, and maintenance. PANLOC is the first professional installation technique to be used on stereo instruments. In the PANLOC system a metal shelf is mounted first. The tuner slides into position on this shelf. Depressing the PANLOC but- tons on the front panel locks the tuner firmly into place for normal operation. To unlock the tuner depress the PANLOC buttons a second time. The tuner can now slide from the front panel. The tuner will lock into this position, preventing accidental release of the tuner from the installation. Depressing the holding latches allows the tuner to be taken out of the PANLOC shelf or to slide back into position against the mounting panel. The finest possible reception of FM mono- phonic and FM multiplex stereophonic broad- casts is assured by the Mclntosh MR 71 tuner. Once you have enjoyed the outstanding performance of the MR 71, you will under- stand why Mclntosh products have earned their reputation as "THE BEST." Your Mc- lntosh MR 71 tuner will give you years of the finest possible FM reception, and will be a valued part of your home music system. 1

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SPECIFICATIONS Useable Sensitivity 2.5 microvolts at 100% modulation (±75KC deviation) for less than 3% total noise and harmonic distortion in accordance with IHF standards. Audio Frequency Response Within ½db from 20 to 20,000 cycles. Distortion Lessthan0.5%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; negli- gible 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 Stages Five, 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. SCA Filter 50db down at 67KC to 74KC 275db per octave slope. Automatic Mono-Stereo Switch An exclusive Mclntosh development; all- electronic automatic mono-stereo switch- ing circuit. (Pat. Pend.). 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, 5th IF 2nd Limiter and Muting. 1-6BN8, Muting Amplifier, Muting Detector, AVC Clamper. 2-6BL8, Left and Right, 1st and 2nd Audio Amplifiers. 1-6U8, MPX Amplifier, MPX Indicator Control. 1-6HU6/EM87 Multipath Indicator. 1-12AU7, MPX Oscillator. 1-ST2-275, Voltage Reference. 1-MA113 (Transistor), MPX Indicator Lamp Switch. 2-1N542 Diodes, Wide Band Discriminator. 2-1N542 Diodes, Narrow Band Discriminator. 4-1N542 Diodes, Balanced MPX Detector. 2-1N542 Diodes, Balanced Detector for MPX Indicator. 2-Selenium Rectifiers, High Voltage Power Supply. 1-No. 1850 Lamp, MPX Indicator. Power Consumption 70 watts, 105 to 125 volts, 50 to 60 cycles. Dimensions Front Panel; 16 inches wide by 57/16 inches high; chassis (including PANLOC shelf) 15 inches wide by 5 inches high by 13 inches deep, including connectors; clearance in front of mounting panel including knobs. 1½ inches. Weight Chassis only, 27 pounds. In shipping carton, 37 pounds. 4

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FM STATION LOG STATION DIAL FREQ. LOG SCALE LOCATION CITY, STATE ANTENNA DIRECTION REMARKS MONO-STEREO-TIME-DATE

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2 CHAMBERS STREET, BINGHAMTON, N. Y. Made in U.S.A. Phone-Area Code 607-723-5491 038-029 BE022003 Printed in U.S.A. LABORATORY INC.