McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York MC312 Power Amplifier Owner’s Manual 13903-2699 Phone: 607-723-3512 www.mcintoshlabs.
Important Safety Information is supplied in a separate document “Important Additional Operation Information Guide” Thank You Customer Service General Information Your decision to own this McIntosh MC312 Stereo Power Amplifier ranks you at the very top among discriminating music listeners. You now have “The Best.” The McIntosh dedication to “Quality,” is assurance that you will receive many years of musical enjoyment from this unit. Please take a short time to read the information in this manual.
Cable Information, Introduction and Performance Features Performance Features Connector and Cable Information XLR Connectors Below is the Pin configuration for the XLR Balanced Input, Input/Output Connectors on the MC312. Refer IN OUT to the diagram for connection: PIN 1: Shield/Ground PIN 2: + Input/Output PIN 1 PIN 2 PIN 2 PIN 1 PIN 3: - Input/Output PIN 3 PIN 3 Power Control Connector The MC312 Power Control Input receives an On/Off signal from +5 to +12 volts.
Dimensions Dimensions The following dimensions can assist in determining the best location for your MC312. Front View of the MC312 17-1/2" 44.5cm 8-7/8" 22.5cm 9-7/16" 24.0cm Side View of the MC312 20" 50.8cm 16-5/8" 42.2cm Rear View of the MC312 16-13/16" 43.0cm 5/8" 1.6cm 13/16" 2.1cm 2-5/8" DISABLED 11-3/4" 29.9cm 4 6.7cm 3/16" 0.5cm 13" 33.1cm 8-1/8" 20.6cm 2-5/8" 6.
Installation Installation The MC312 can be placed upright on a table or shelf, standing on its four feet. It also can be custom installed in a piece of furniture or cabinet of your choice. The four feet may be removed from the bottom of the MC312 when it is custom installed as outlined below. The four feet together with the mounting screws should be retained for possible future use if the MC312 is removed from the custom installation and used free standing.
Rear Panel Connections and Switch Balanced OUTputs (LEFT and RIGHT Channels) for an audio cable to the next Power Amplifier Input Unbalanced INput (RIGHT Channel) for an audio cable from a Preamplifier or A/V Control Center audio output.
Output Terminals and How to Connect Output Terminals When connecting the Loudspeaker Hookup Cables to the MC312 Power Amplifier Output Terminals please follow the steps below: 1. Rotate the top of the Output Terminal Post counterclockwise until an opening appears. Refer to figures A and B. 2. Insert the Loudspeaker hookup cable into the Output Terminal Opening Post opening or the cable spade Figure B Figure A lug around the center post of the Output Terminal. Refer to figure C. 3.
Output Terminals and How to Connect, con’t MC312 COM (Negative) Output Terminal and Positive Output Terminal indentified as 2Ω (ohms), 4Ω (ohms) or 8Ω (ohms) connection to match the impedance of the Loudspeaker, being careful to observe the correct polarities. Note: The illustration on separate sheet “Mc1A”is connections for 8Ω (ohms) Loudspeakers. If the Loudspeaker’s impedance is in-between the available connections, use the nearest lower impedance connection.
Output Terminals and How to Connect for Bi-Amp Output Terminals When connecting the Loudspeaker Hookup Cables to the MC312 Power Amplifier Output Terminals please follow the steps below: 1. Rotate the top of the Output Terminal Post counterclockwise until an opening appears. Refer to figures A and B. 2. Insert the Loudspeaker hookup cable into the Output Terminal Opening Post opening or the cable spade Figure B Figure A lug around the center post of the Output Terminal. Refer to figure C. 3.
Output Terminals and How to Connect for Bi-Amp 7. Rotate the top of the Output Terminal Post clockwise until it is finger tight. Refer to figure G. Then using the McIntosh Wrench, rotate the top of the Output Terminal one quarter of a turn Figure G (90° ). Do not over tighten. Refer to figure E on page 9. 8.
Front Panel Displays and Controls Meter indicates the Left Channel Output of the amplifier LED indicates when the LEFT Channel Amplifier POWER GUARD circuit activates METER Switch selects the display modes of the Power Output Meter and Meter Illumination 12 Standby Power On Indicator LED indicates when the RIGHT Channel Amplifier POWER GUARD circuit activates Meter indicates the Right Channel Output of the amplifier POWER Switch Turns AC Power Off, Remote, AC Power On
How to Operate How to Operate Power On To have the MC312 automatically turn On or Off when a Preamplifier or A/V Control Center turns On or Off, rotate the power switch to the Remote position. For manual operation, rotate the power switch to the On or Off position as desired. Refer to figure 9. Watts- The meters respond to all the musical information being produced by the amplifier. They indicate to an accuracy of at least 95% of the power output with only a single cycle of a 2000Hz tone burst.
Technical Description McIntosh Laboratory, the company who introduced the world’s first amplifier that could be called “High Fidelity”, has done it again. The McIntosh engineering staff has created a power amplifier without compromise, using the most advanced McIntosh circuit design concepts. The MC312 has a continuous average power output rating of 300 watts per channel, with a peak output current of 60 amperes, making it one of the most advanced amplifiers available today.
Technical Description may vary considerably from what a loudspeaker requires. In the case of more than one loudspeaker connected in parallel, the load to the power amplifier may drop to two ohms or even less. A power amplifier connected to a load that is lower than optimum, causes more output current to flow, which results in extra heat being generated in the power output stage. This increase in temperature will result in a reduced life expectancy for the amplifier.
Technical Description, con’t Refer to figure 18. There is absolutely no performance limitation with an Autoformer. Its frequency response exceeds that of the output circuit itself, and extends well beyond the audible range. Its distortion level is so low it is virtually impossible to measure. In the rare event of a power amplifier output circuit failure, the McIntosh Autoformer Figure 18 provides absolute protection from possible damage to your valuable loudspeakers.
Technical Description, con’t perfectly preserved. The MC312 Power Amplifier with Power Guard is not limited to just the rated power output, but will actually produce distortion free output well above its rated power due to the McIntosh philosophy of conservative design. With Power Guard BACKUP POWER SUPPLY AC Power Figure 23 Power Supply Circuits To compliment the design of the MC312 Power Amplifier Circuitry, there is a high current high voltage power supply for both channels.
Specifications Specifications Power Output Minimum sine wave continuous average power output per channel, with both channels operating is: 300 watts into 2 ohm load 300 watts into 4 ohm load 300 watts into 8 ohm load Output Load Impedance 2, 4 or 8 ohms Intermodulation Distortion 0.005% maximum, if the instantaneous peak power output does not exceed twice the rated power output for any combination of frequencies from 20Hz to 20,000Hz.
Packing Instructions Packing Instructions In the event it is necessary to repack the equipment for shipment, the equipment must be packed exactly as shown below. It is very important that the four plastic feet are attached to the bottom of the equipment. Four 1/4 - 20x2-1/4 inch screws and washers must be used to fasten the unit securely to the bottom pad and wood skid. This will ensure the proper equipment location on the bottom pad. Failure to do this will result in shipping damage.
McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, NY 13903 www.mcintoshlabs.com The continuous improvement 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 Part No.
