McIntosh MR 77 FM Tuner One Owner AUDIOPHILE SERVICED A, NEAR COND

MCINTOSH MR 77 FM TUNER, ONE OWNERCONDITION: NEAR MINT to MINT. Excellent, Very clean, Minimal signs of use. SERVICED & TESTED TESTED A+: Fully functional, Everything works as it should ~ PHOTOS are considered part of the description, so please view them for more details and a better understanding of the quality. ~ SERVICED: All dust has been carefully removed interior of the unit. The faceplate was removed, thoroughly cleaned and polished. The INNER tuning glass dial was removed, ...thoroughly cleaned and polished. Both glass plates are crystal clear. The deteriorated foam securing the faceplate glass has been replaced with rubberized foam to properly secure and protect the faceplate glass from damage. All knobs were removed and polished. Lamps have been checked and replaced where needed. All solder joints have been checked with a jewelers loupe for cold solder and reflowed where necessary. The control pots and switches have been cleaned and lubed for years of smooth and silent operation. New McIntosh 1” factory plastic feet have been installed. ~ EXPERT SHIPPING: READ IN DETAILSORIGINAL MCINTOSH CABINET WITH CORRECT PANLOCS IS AVAILABLE IN MY EBAY STORE.Mclntosh research is a continuous program of exploration for new technology that permits performance improvement and greater value for you. This intensive research program developed the new technology necessary for the realization of these two new design concepts for the MR 77.1 THE LINEAR PHASE IF FILTEREven since the beginning of FM, research engineers have realized that constant delay, or linear phase, IF filters were necessary for low distortion reception. Crude approximations to constant delay have always been used in FM tuners — with disappointing results. So-Called "Butterworth" or "Legandre" filters offer only a fair compromise with respect to delay error. Crystal and ceramic filters, usually based on the "Chebychev" model, work fairly well and give good selectivity, but none of these are constant delay (linear-phase) filters. Commercial tuners using these filters can show 5% stereo IM distortion at 100% modulation, and have delay errors up to 100%. In sharp contrast, the linear phase filter allows a tuner to show only .1% IM distortion at 100% modulation and has a delay error of only 1.2% in the useful bandpass. In its useful bandpass, it is a true mathematical approximation to linear-phase — the world's finest selective, linear-phase, minimum-phase shift filter.A FORTRAN computer program using an algorithm that took six years to develop was used in its design. The mathematical complexity of the filter design procedure is almost beyond belief. Using a process called "numerical integration in the complex S-plane, " a high speed IBM 1130 computer spent eighteen minutes on the design of the MR 77 IF filter. A human engineer, working twenty-four hours a day and seven days a week, would have taken 300 years to finish this work . . . assuming he made no mistakesl2 LINEAR PHASE BRIDGE DISCRIMINATORThe linear phase filter would be useless if it had to work into an ordinary FM detector. Thus a new detector with suitably low distortion had to be developed. A search of the available literature revealed a little-known bridge circuit with a theoretical distortion of zero! However, designing a practical working circuit for a commercially feasible stereo tuner took some doing. A U. S. patent is pending on this circuit.Distortion performance of the bridge detector is close to the theoretical zero. In addition to its excellent distortion performance, the bridge detector also exhibits capture ratio close to 0 dB. The linear-phase bridge discriminator uses a balanced transmission line bridge in conjunction with a differential voltage-doubling rectifier to achieve 99.9% accuracy demodulation of FM signals. The only adjustments in the MR 77 detector are two simple variable resistors.These resistors center the tuning meter and set the transistor bias. Complex tuning for minimum distortion is not needed.
SPECIFICATIONS Performance Limits are the maximum deviation from perfection permitted for a Mclntosh instru- ment. We promise you that the MR77 you buy must be capable of performance at or exceeding the limits or you get your money back. Mclntosh is the only manufacturer that makes this guarantee. USABLE SENSITIVITY2 microvolts for 35 dB of quieting; 2.5 microvolts at 100% modulation (±75 kHz deviation) for 3% total noise and harmonic distortionSIGNAL TO NOISE RATIO75 dB below 100% modulationHARMONIC DISTORTIONWill not exceed 0.2% mono or stereo at 100% modulation, 20 Hz to 15, 000 HzINTERMODULATION DISTORTIONWill not exceed 0.2% mono or stereo for any com- bination of frequencies from 20 Hz to 15, 000 Hz with peak modulation equal to 100% or less. Typically 0.1%AUDIO FREQUENCY RESPONSE±1 dB 20 Hz to 15, 000 Hz with standard de-emphasis, (75 μS) and 19, 000 Hz pilot filter CAPTURE RATIO0.25 dB detector only2.5 dB complete tuner at 100% modulation SPURIOUS REJECTION100 dB.IMAGE REJECTION100 dB; 88 to 108 MHz (IHF)SELECTIVITYAdjacent channel 6 dB IHF, carrier 47 dB down Alternate channel 50 dB IHF, carrier 90 dB downSTEREO SEPARATION 40 dB at 1, 000 HzSTEREO FILTER10 dB noise reduction in position 1 20 dB noise reduction in position 2SCA FILTER50 dB down from 67 kHz to 74 kHz 275 dB per octave slopeDRIFT25, 000 Hz in first two minutes; thereafter 5, 000 Hz in normal temperaturesMUTING70 dB noise reduction between stationsMUTING THRESHOLD Position 1, 5 microvolt Position 2, 20 microvoltANTENNA INPUTS300 ohms balanced; 75 ohms unbalancedMAXIMUM SIGNAL INPUT12 RF volts across 300 ohms antenna terminals will not increase harmonic or intermodulation distor- tionAUDIO OUTPUT2.5 volts into 47, 000 ohms1 volt into 600 ohms from fixed outputIF SYSTEM8-Pole linear phase filter2IC's1 J-FET, and push-pull overlay power transistor stage driving a linear phase bridge discriminatorSTEREO INDICATORFront panel stereo light activated by 19, 000 HzonlyAUTOMATIC MONO-STEREO SWITCHMclntosh developed; all electronic automaticmono-stereo switching circuit SEMICONDUCTOR COMPLEMENT21 Transistors4 Integrated Circuits 1 Indicator TubePOWER REQUIREMENT120 volts 50/60 Hz, 35 wattsMECHANICAL INFORMATIONFRONT PANEL16 inches wide (40.64 cm) by 5-7/16 inches high (13.81 cm)CHASSIS15 inches wide (38.1 cm) by 13 inches deep (33.02 cm) including PANLOC shelf and back panel con- nectors. Knob clearance: 11⁄2 inches (3.81 cm) in front of mounting panelFINISHFront Panel: Anodized gold and black with special gold/teal nomenclature illumination. Chassis Chrome and blackMOUNTINGMclntosh developed professional PANLOCWEIGHT27 pounds (12.25 kg) net39 pounds (17.69 kg) in shipping carton

SHIPPINGWe have much experience successfully shipping sensitive electronics. Fast shipping, typically with a one day turnaround time.*Please review our feedback.*We professionally package your purchase in house and we are experts in shipping electronics such as these. We properly secure the shipment and get it to you like it left us.We take pride in our packing abilities and this will be evident from the moment your package arrives.Full insurance is included as well to protect both of our interests. If an item arrives damaged, the buyer is responsible to notify the seller immediately, retain all shipping materials, and upon request make them available to FedEx for inspection. Failure to cooperate may void your claim and rights to a refund. If a refund is due, the buyer agrees to wait for funds from FedEx. If FedEx denies the claim, the seller may still indemnify.Your item will be shipped via FedEx Ground and the tracking number can be found in “My eBay” under “Purchase History”. However, the most up to date status of your package will be found online at FedEx.com, not on eBay.SHIPPING QUOTED IS FOR THE LOWER 48 STATES, OTHERWISE MESSAGE ME FOR A QUOTEFedEx Ground does not ship to PO Boxes or AFB, APO, FPO, or DPO addresses.

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