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McIntosh Laboratory, Inc.    2 Chambers Street Binghamton, New York    13903-2699 Phone: 607-723-3512    FAX: 607-724-0549

MC275

Owner’s Manual

Stereo Power Amplifier

Summary of Contents for MC275

Page 1: ...McIntosh Laboratory Inc 2 Chambers Street Binghamton New York 13903 2699 Phone 607 723 3512 FAX 607 724 0549 MC275 Owner s Manual Stereo Power Amplifier ...

Page 2: ...rvicing instructions in the litera ture accompanying the appliance WARNING TO REDUCE RISK OF FIRE OR ELECTRICAL SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED PERSONNEL To prevent the risk of electric shock do not remove cover or back No user serviceable parts inside IMPORTANT SAFETY INSTRUCTIONS PLEASE READ THEM BEFORE OPERATIN...

Page 3: ...epartment For assistance on factory repair return procedure contact the McIntosh Service Department at McIntosh Laboratory Inc 2 Chambers Street Binghamton New York 13903 Phone 607 723 3515 Fax 607 723 1917 Copyright 2006 by McIntosh Laboratory Inc Table of Contents General Information Safety Instructions 2 Thank You and Please Take a Moment 3 Technical Assistance and Customer Service 3 Table of C...

Page 4: ...nto 4 8 or 16 ohm Loud speakers in stereo It may also be operated in mono at 150 watts into 2 4 or 8 ohm Loudspeakers Bifilar Wound Transformers and Output Circuit The Power Output Sections utilize the famous McIntosh Patented Unity Coupled Circuit with a Bifilar Wound Output Transformer for low distortion extended frequency response and cool operating output tubes Balanced and Unbalanced Inputs B...

Page 5: ...ditional infor mation on page 7 pertaining to installing the MC275 into cabinets 16 1 2 41 91cm Front View of the MC275 Top View of the MC275 Left Side View of the MC275 Right Side View of the MC275 7 7 8 20 00cm 8 1 4 20 96cm 13 5 8 34 61cm 12 30 48cm 1 3 4 4 45cm 1 3 4 4 45cm 1 1 4 3 18cm 4 3 8 11 11cm 5 9 16 14 13cm ...

Page 6: ...foam and temporarily place them in a safe location 6 Remove the remaining foam from the Tube Cover and retain all four pieces for possible future use The MC275 Chassis has nomenclature screened on it to specify both the circuit location and Tube Type for each channel Refer to figure 4 Note It is extremely important to insert the Tubes in the correct location Power Output Tubes 1 Orient the Chassis...

Page 7: ... and perform the following steps Installing the Tube Cover 1 The Tube Cover has a wide opening along one side of its longer dimension Orient this wide opening so it is facing towards the three large transformers 2 Carefully place the Tube Cover onto the MC275 while at the same time aligning the two chassis mounted ball studs with the Tinnerman Clips in the cover Refer to figure 6 The MC275 can be ...

Page 8: ... Connections for loudspeakers RIGHT OUTPUT Connections for loudspeakers BALANCED INPUTS for audio cables from a preamplifier or control center audio outputs UNBALANCED INPUTS for audio cables from a preamplifier or control center audio outputs ...

Page 9: ...older Connect the MC275 power cord to a live AC outlet Refer to information on the back panel to determine the correct voltage Main Fuse holder refer to information on the back panel of your MC275 to determine the correct fuse size and rating ...

Page 10: ...C275 Amplifier until after the Loudspeaker Connec tions have been made When connecting Loudspeakers to the MC275 it is very important to use cables of adequate size so there is little to no power loss in the cables The size is specified in Gauge Numbers or AWG American Wire Gauge The smaller the Gauge number the larger the wire size If your loudspeaker cables are 50 feet 38 1m or less use at least...

Page 11: ...least 14 Gauge If your loudspeaker cables are 100 feet 76 2m or less use at least 12 Gauge 1 Prepare the Loudspeaker Hookup Cable and Jumper Wires for connection to the Power Amplifier Output Terminals two 5 1 4 inch 13 34 cm Jumper Wires and one Loudspeaker Hookup Cable cut to the desired length Prepare the cable and wires by choosing one of the methods below Bare wire cable ends Carefully remove...

Page 12: ...eft Side Panel Controls and Switches Power Switch turns all AC power On or Off MODE Switch selects MONO Parallel or STEREO Modes of operation INPUTS Switch selects between the BALanced or UNBALanced Inputs ...

Page 13: ...ontrol Center or A V Center the addition of a Mc Intosh Power Controller such as a PC4 will allow the MC275 to switch On and Off automatically Mode Switch The MODE Switch which is located on the Left Side Panel of the MC275 allows selection of either Stereo or Mono Parallel Modes of Operation Refer to figure 9 and pages 10 and 11 for connec tion information Input Switch When BALANCED Input Connect...

Page 14: ...th both channels operating is 0 5 A Weighted Signal To Noise Ratio 100dB Frequency Response 0 0 5dB from 20Hz to 20 000Hz 0 3dB from 10Hz to 70 000Hz Sensitivity 1 2 Volt unbalanced inputs 2 5 Volt balanced inputs Input Impedance 90 000 ohms unbalanced inputs 180 000 ohms balanced inputs Wide Band Damping Factor Greater than 14 Tube Compliment 3 12AX7A Inputs and Phase Inverters 4 12AT7 Voltage Am...

Page 15: ...he bottom of the equipment This will ensure the proper equipment location on the bottom pad Failure to do this will result in shipping damage Use the original shipping carton and interior parts only if they are all in good serviceable condition If a shipping carton or any of the interior part s are needed please call or write Customer Service Department of McIntosh Labo ratory Please see the Part ...

Page 16: ...of its products is the policy of McIntosh Laboratory Incorporated who reserve the right to improve design without notice Printed in the U S A McIntosh Laboratory Inc 2 Chambers Street Binghamton NY 13903 McIntosh Part No 04099600 ...

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