McIntosh MC 303 Owners Manual

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2 The lightning flash with arrowhead, within an equilateral triangle, is intended to alert the user to the presence of uninsulated danger - ous voltage within the products enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. 1. Read these instructions. 2. Keep these instructions. 3. Heed all warnings. 4. Follow all instructions. 5. Do not use this apparatus near water. 6. Clean only with a dry cloth. 7. Do not block any ventilation openings. Install in accordance with the manufacturers instructions. 8. Do not install near any heat sources such as radia - tors, heat registers, stoves, or other apparatus (including amplifiers) that produce heat. 9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug has two blades with one wider than the other. A ground - ing type plug has two blades and a third ground - ing prong. The wide blade or the third prong are provided for your safety. If the provided plug does not fit into your outlet, consult an electrician for replacement of the obsolete outlet. 10. Protect the power cord from being walked on or pinched particularly at plugs, convenience re - ceptacles, and the point where they exit from the apparatus. The exclamation point within an equilateral triangle is intended to alert the user to the presence of im - portant operating and maintenance (servicing) 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 OPERATING THIS EQUIPMENT. 11. Only use attachments/accessories specified by the manufacturer. 12. Use only with the cart, stand, tripod, bracket, or table specified by the manufacturer, or sold with the apparatus. When a cart is used, use caution when mov - ing the cart/apparatus combination to avoid injury from tip-over. 13. Unplug this apparatus during lightning storms or when unused for long periods of time. 14. Refer all servicing to qualified service person - nel. Servicing is required when the apparatus has been damaged in any way, such as power-supply cord or plug is damaged, liquid has been spilled or objects have fallen into the apparatus, the appara - tus has been exposed to rain or moisture, does not operate normally, or has been dropped. 15. Do not expose this equipment to dripping or splashing and ensure that no objects filled with liq - uids, such as vases, are placed on the equipment. 16. To completely disconnect this equipment from the a.c. mains, disconnect the power supply cord plug from the a.c. receptacle. 17. The mains plug of the power supply cord shall remain readily operable. 18. Do not expose batteries to excessive heat such as sunshine, fire or the like.

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3 Thank You Your decision to own this McIntosh MC303 Power Ampli - fier ranks you at the very top among discriminating music listeners. You now have The Best. The McIntosh dedica - tion 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. We want you to be as familiar as possible with all the features and functions of your new McIntosh. Please Take A Moment The serial number, purchase date and McIntosh Dealer name are important to you for possible insurance claim or future service. The spaces below have been provided for you to record that information: Serial Number: __________________________________ Purchase Date: __________________________________ Dealer Name: ___________________________________ Technical Assistance If at any time you have questions about your McIntosh product, contact your McIntosh Dealer who is familiar with your McIntosh equipment and any other brands that may be part of your system. If you or your Dealer wish additional help concerning a suspected problem, you can receive technical assistance for all McIntosh products at: McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903 Phone: 607-723-1545 Fax: 607-724-0549 Customer Service If it is determined that your McIntosh product is in need of repair, you can return it to your Dealer. You can also return it to the McIntosh Laboratory Service Department. 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 2008 © 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 Contents ............................................................... 3 General Information ....................................................... 3-4 Connector Information ...................................................... 4 Introduction ........................................................................\ 4 Performance Features ........................................................ 4 Dimensions ........................................................................\ 5 Installation ........................................................................\ . 6 Rear Panel Connections and Switch .................................. 7 How to Connect .............................................................. 8-9 Connection Diagrams (Separate Sheet) MC1A and MC1B Front Panel Displays and Controls .................................... 10 How to Operate ................................................................. 11 Technical Description .................................................. 12-15 Photos ........................................................................\ ... 16 -17 Specifications .................................................................... 18 Packing Instruction ........................................................... 19 Caution: The MC303 Amplifier weight is 150 pounds (70.3 kilograms). It requires two or more persons to safely handle when moving the amplifier. 1. The following Connecting Cable is available from the McIn - tosh Parts Department: Power Control Cable Part No. 170-202 Six foot, 2 conductor shielded, with two 1/8 inch stereo mini phone plugs. 2. For additional connection information, refer to the owners manual(s) for any component(s) connected to the MC303. 3. The MC303 mutes the speaker output for approximately two seconds when first turned on. 4. In the event the MC303 overheats, due to improper ventilation and/or high ambient temperature, the protection circuits will activate. The Front Panel Power Guard LEDs will continu - ously indicate ON and the audio will be muted. When the MC303 has returned to a safe operating temperature, normal operation will resume. 5. For the best performance it is important to minimize an im - pedance mismatch. An impedance mismatch can occur when a Loudspeaker of a given impedance rating is connected to the MC303 Output Terminals with a different impedance rating. For example, a Loudspeaker with an impedance rating of 2 Ohms is connected to the MC303 8 Ohm Output Terminals. The impedance of a Loudspeaker actually varies as the Loudspeaker reproduces different frequencies. As a result, the nominal impedance rating of the Loudspeaker (usually mea - sured at a midrange frequency) might not always agree with the impedance of the Loudspeaker at low frequencies where the greatest amount of power is required.