McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York MA252 Integrated 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 Your decision to own this McIntosh MA252 Integrated 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.
IMPORTANT! INSTRUCTIONS FOR REMOVAL OF FOAM INSERT OVER THE VACUUM TUBES PRIOR TO CONNECTING THE A.C. POWER SUPPLY CORD, START ON THE NEXT PAGE.
Caution: To prevent damage to the MA252 Tubes during shipping, there is a special foam insert surrounding the Tubes of the Integrated Amplifier. 2. Remove the Warning Sheet and save it with the Shipping Carton for possible future use. Refer to figures A and B. 3. Carefully lift upright the Foam Insert Vacuum Tube Cover and place it near to the MA252 Integrated Amplifier. Refer to figure C.
Unpacking the MA252 WARNING: The supplied Vacuum Tube Shield Covers must be installed over each of the four Small Vacuum Tubes before the MA252 Integrated Amplifier is connected to AC Power and activated for use!! 5. The MA252 Integrated Amplifier has four Small Vacuum Tubes that are inserted into special Vacuum Tube Sockets on the Stainless Steel Chassis. Refer to figure E. Each of the Tube Sockets have four pin openings to accept the Vacuum Tube Shield Covers. Refer to figure F.
General Information, Connector and Cable Information General Information 1. For additional connection information, refer to the owner’s manual(s) for any component(s) connected to the MA252. 2. Apply AC Power to the MA252 and other McIntosh Component(s) only after all the system components are connected together. Failure to do so may cause a malfunction of system operations as the Microprocessor’s Circuitry inside the components is active when AC Power is applied. 3.
Introduction and Performance Features Introduction Now you can take advantage of traditional McIntosh standards of excellence in the MA252 Integrated Amplifier. The Power Amplifier Solid State section of the MA252, with a power output of 100 watts per channel, will drive a pair of quality Loudspeakers to a high level of performance. The flexible Tube Preamplifier section provides connections for various analog input sources. The MA252 reproduction is sonically transparent and absolutely accurate.
Dimensions Dimensions The following dimensions can assist in determining the best location for your MA252. There is additional information on the next page pertaining to installing the MA252 into cabinets. Left Side View of the MA252 Front View of the MA252 16-1/2" 41.9cm 1-1/2" 3.8cm BAL 7-1/32" 17.9cm 15% 7-5/8" 19.4cm 1-1/2" 3.8cm Top View of the MA252 1-1/2" 3.8cm Right Side View of the MA252 14-3/4" 37.5cm 6-13/16" 17.3cm 4-1/16" 10.3cm 12" 30.5cm 3" 7.
Installation Installation The MA252 Integrated Amplifier is designed to be placed upright on a table or shelf, standing on its feet. The required ventilation requirements are shown. Always provide adequate ventilation for your MA252. Cool operation ensures the longest possible operating life for any electronic instrument. Do not install the MA252 directly above a heat generating device, such as a Power Amplifier. Allow at least 6 inches (15.3cm) above the top, 5/8 inch (1.
MA252 Rear Panel Connections Right OUTPUT connections for a 4 or 8 ohm Loudspeaker POWER CONTROL OUTPUT sends turn On/Off signals to a McIntosh Component when the MA252 is switched On/Off Left OUTPUT connections for a 4 or 8 ohm Loudspeaker PHONO accepts signals from a Moving Magnet Phono Cartridge or a high output Moving Coil Cartridge Main Fuse holder, refer to information on the back panel of your MA252 to determine the correct fuse size and rating DATA PORT sends signals to a Source Component to al
Connecting Components The MA252 has the ability to automatically switch power On/Off to McIntosh Source Components via the Power Control connections. The Data Port Connections allow for the remote operation of basic functions using the MA252 Remote Control. The connection instructions below, together with the MA252 Input and Output Connection Diagram on the next page is an example of a typical audio system. Your system may vary from this, however the actual components would be connected in a similar manner.
Connecting Components Connect to AC Outlet Turntable CD Player 12
Output Terminals When connecting the Loudspeaker Hookup Cables to the MA252 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.
Connecting Loudspeakers 5. Connect the MA252 power cord to an active AC outlet. Spade Lug or Wire Connections: 6. Connect the Loudspeaker hookup cables to the MA252 Negative Output Terminal and Positive Output Terminal to the Loudspeaker Terminal Connections being careful to observe the correct polarities.
HR091 Remote Control Push-Buttons Mutes and unmutes the audio LED illuminates during the time a remote command is sent to the MA252 Powers the MA252 ON or OFF Decreases the volume level Increases the volume level Directional Push-buttons - Up, Down, Left and Right Select the desired active TRIM function; also manually tune up the dial with contemporary McIntosh Tuners Adjusts the active TRIM Function Adjusts the active TRIM Function Select the desired active TRIM function; also manually tune down th
How to use the Remote Control How to use the Remote Control The supplied Remote Control performs the various Operating Functions for the MA252 Integrated Amplifier. Note: Refer to the “How to Operate” Section of this manual for additional information. Input Source Selection Press the Push-button → to select the desired program source. Volume Press the + or - Push-buttons to increase or decrease the listening level. Mute Press the (Mute) Push-button to mute the audio and a second time to resume listening.
Front Panel Displays, Controls and Jack INPUT Control used to select a source for listening and recording. The control is also used to enter the TRIM or SETUP Modes and select the various functions Preamplifier Small Signal Vacuum Tube LED Illumination Color: Orange- Warmup Mode and Power Guard Activates Green - Normal Operation BAL IR Sensor receives commands from a Remote Control VOLUME Control allows adjustment of the listening level for both channels. Switches the MA252 ON or OFF (Standby).
Setup How to Operate the Setup Mode Your McIntosh MA252 has been factory configured to allow immediate enjoyment of superb audio without the need for further adjustments. If you wish to make changes to the factory default settings, a Setup Feature is provided to customize the operating settings using the Front Panel Information Display. Refer to the MA252 Front Panel Illustration on the previous page while performing the following steps. Note: If the MA252 is currently On, proceed to step 2. 1.
Input Settings, con’t 2. Rotate the INPUT Control until “SETUP: Inputs, (Hold INPUT)” appears on the Information Display. Refer to figure 3 on page 19. 3. Press and hold in the INPUT Control until “SETUP: UNBAL 2, On / Name (Hold IN)” appears on the Display. If necessary rotate the INPUT Control to select the UNBAL 2 Input. Refer to figure 5. SETUP: UNBAL 2 On/Name(Hold IN) Figure 5 4. To switch the UNBAL 2 Input Off, rotate the VOLUME Control until the display indicates “SETUP: UNBAL 2, Off”.
Setup, con’t Remote Control Codes 19. Rotate the INPUT Control until the “_” empty space to the right of character P is flashing, then rotate the VOLUME (ADJUST) Control to change the “_” empty space to character to “L”. Refer to figure 14. RENAME: BAL >CD PL Figure 14 20. Repeat step 19 until the new name of “ RENAME: BAL, CD PLAYER” is indicated on the Front Panel Display. Refer to figures 15 thru 18.
Setup, con’t IR Sensor Power Mode Factory Reset The MA252 Front Panel Sensor, which receives the signals from the HR091 Remote Control, can be switched off to prevent interference when other Remote Control IR Signals are received. To de-activate the Front Panel IR Sensor perform the following steps: 1. Press and hold in the INPUT Control to enter the SETUP MODE. Refer to figure 2 on page 19. 2. Rotate the INPUT Control until “SETUP: Front IR, Enabled” appears on the Information Display.
How to Operate the MA252 Power On and Off The Red LED to the left of the VOLUME Control lights to indicate the MA252 is in Standby mode. To switch ON the MA252, Press the VOLUME Control on the Front Panel or press the Push-button on the Remote Control. The MA252 will go through a Tube Warmup Initialization procedure. Refer to figure 50. Tubes LED will be illuminated with the Amber Color. Then sound will be heard and the LED illumination color of the Small Signal Vacuum Tubes will change to the Green Color.
How to Operate the MA252 2. Rotate the VOLUME Control or press the ◄ ► (Left or Right) directional Push-buttons to make a change to the current Balance Setting to emphasize the Right Channel (refer to figure 56) or the Left Channel (refer to figure 57). L BALANCE R ¦ ¦¦¦¦ ¦¦¦ ¦ Figure 56 L BALANCE ¦ ¦¦¦¦ ¦¦¦¦ R Figure 57 The Front Panel Display indicates the relative Balance changes. After approximately 6 seconds, the Display returns to indicate the Source Selection and Volume Level.
How to Operate the MA252, con’t form the following: 1. Use the Front Panel INPUT/TRIM Control or the TRIM Push-button on the Remote Control until “TREBLE, 0 dB” appears on the Front Panel Information Display. Refer to figure 66. 2. Rotate the VOLUME Control or press the ◄ ► in steps from +10dB to -10dB. After approximately 6 seconds the Display returns to indicate the Source Selection and Volume Level.
How to Operate the MA252, con’t Tubes LED Illumination is the color green. During peaks in the audio signals when the Power Guard Circuitry is activated, the LED Illumination will change to the amber color. Protection Circuitry In the event the MA252 over heats, due to improper ventilation, high ambient temperature and/or impedance mismatch, the internal protection circuits will activate. The small Signal Vacumn Tubes normal LED Illuminated Color of Green, will change to an Amber Color.
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Specifications Amplifier Specifications Power Output Stereo Minimum sine wave continuous average power output per channel, with both channels operating is: 100 watts into 8 ohm load 160 watts into 4 ohm load Output Load Impedance 8 or 4 ohms Rated Power Band 20Hz to 20,000Hz Total Harmonic Distortion 0.03% maximum with both channels operating from 250 milliwatts to rated power, 20Hz to 20,000Hz Intermodulation Distortion 0.
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 feet are attached to the bottom of the equipment. This will ensure the proper equipment location on the bottom foam pad. Failure to do this will result in shipping damage. To protect the tubes during shippment, the Foam Insert removed from the MA252 needs to be re-inserted.
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.
