McIntosh MC 501 Owners Manual

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2 IMPOR T ANT SAFETY INSTRUCTIONS! PLEASE READ THEM BEFORE OPERATING THIS EQUIPMENT. WARNING - TO REDUCE RISK OF FIRE OR ELECTRICAL SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE. The lightning flash with arrowhead, within an equilateral triangle, is intended to alert the user to the presence of uninsulated dangerous voltage within the products enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. 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. The exclamation point within an equi- lateral triangle is intended to alert the user to the presence of important operating and maintenance (servic- ing) instructions in the literature ac- companying the appliance. 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 radiators, 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 grounding type plug has two blades and a third grounding 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 receptacles, and the point where they exit from the apparatus.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 moving 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 personnel. 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 apparatus 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 liquids, 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.

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3 Customer Service Technical Assistance Please Take A Moment Thank You Copyright 2003  by McIntosh Laboratory, Inc. 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: Your decision to own this McIntosh MC501 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. Serial Number: Purchase Date: Dealer Name: 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 as- sistance 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 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 addi- tional help concerning a suspected problem, you can re- ceive technical assistance for all McIntosh products at: McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903 Phone: 607-723-1545 Fax: 607-723-3636 Table of Contents Important Information Caution: The MC501 Amplifier weight is 91.5 pounds (41.5 kilograms). It requires two or more persons to safely handle when moving the amplifier. 1. The following Connecting Cable is available from the McIntosh 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 owner s manual(s) for any component(s) connected to the MC501. 3. The MC501 mutes the speaker output for approximately two seconds when first turned on. 4. It is very important that loudspeaker cables of adequate size be used, so that there will be no power loss. 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 14 Gauge. If your loudspeaker cables are 100 feet (76.2m) or less, use at least 12 Gauge. 5. In the event the MC501 over heats, due to improper ventilation and/or high ambient temperature, the protection circuits will activate. The Power Guard LED will stay ON and the audio will be muted. When the MC501 has returned to a safe operating temperature, normal operation will resume. 6. The MC501 incorporates Fully Double Balanced Circuitry. As a result, the Loudspeaker Negative Connections are above chassis ground. Do not combine any connections together, ground them or connect with another MC501. Safety Instructions............................................................ 2 Thank You and Please Take a Moment............................. 3 Technical Assistance and Customer Service.................... 3 Table of Contents and General Notes............................... 3 Connector Information..................................................... 4 Introduction ...................................................................... 4 Performance Features....................................................... 4 Dimensions ....................................................................... 5 Installation ........................................................................ 6 Top Panel Connections and Switch .................................. 7 How to Connect................................................................ 8 Front Panel Displays and Controls ................................. 10 How to Operate............................................................... 11 Technical Description..................................................... 12 Notes ............................................................................... 16 Specifications ................................................................. 18 Packing Instruction ......................................................... 19

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11 How to Operate How to Operate Power On To have the MC501 automatically turn On or Off when a 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 10. Note: There must be a power control connection between the MC501 and the McIntosh Control Center, in order for the remote power turn on to function. Meter Selection Rotate the meter mode switch to select the meter operation mode you desire. Refer to figures 11 and 12.Lights Off - Meter lights are turned off and the meter will continue to indi- cate the power output. Watts- The meter re- spond to all the musical informa- tion being pro- duced by the am- plifier. They indicate to an accuracy of at least 95% of the power output with only a single cycle of a 2000Hz tone burst. Hold - The meter pointer is locked to the highest power peak in a sequence of peaks. It is elec- tronically held to this power level until a higher power peak passes through the ampli- fier. The meter pointer will then rise to the newer higher indication. If no further power Figure 10 Figure 12 Figure 13 peaks are reached, the meter pointer will very slowly return to its rest position or lower power level. The decay rate is approximately 6dB per minute. Note: The MC501 Power Output Meterindicates the actual wattage delivered to the Loudspeakers by responding to the combination of current and voltage output. Input Mode Switch The Input Mode Switch, which is located on the Top Rear Panel of the MC501, allows selection of either the Bal- anced or Unbalanced Input. Refer to figure 13. Figure 11

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14 Figure 18 Input Test Signal The special Balanced Winding Autoformer creates an ideal match between the power amplifier output stage and the loudspeaker. A McIntosh amplifier with an Autoformer can be used to safely drive multiple speakers without re- ducing the life expectancy of the power amplifier. Refer to figure 15. There is absolutely no performance limitation with an Autoformer. Its frequency response exceeds that of the out- put 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 fail- ure, the McIntosh Autoformer provides absolute protection from possible damage to your valuable loudspeakers. The unequaled expertise of McIntosh in the design and manu- facturing of Autoformers is legendary in the high fidelity industry. McIntosh engineers know how to do it right. Power Output Meter The McIntosh MC501 has a Output Watt Meter that re- sponds 95% full scale to a single cycle tone burst at 2kHz. Refer to figure 16. Voltage and current output are electroni- cally measured, multiplied and fed to a special circuit that accelerates the pointer movement in the upward direction. When the pointer reaches its peak it pauses only long enough for the human eye to perceive its position, then drops. It is almost 10 times faster than a professional VU meter. A front panel switch is provided to change the meter to the Watts Hold Mode of operation. This allows fast upward movement of the pointer but greatly increases Hold Time at the peak of its travel. The highest power output of the source material is thus recorded.Protection Circuits The MC501 incorporates a version of the McIntosh Sentry Monitor Output Transistor Protection Circuit. Refer to Fig- ure 17. There is absolutely no compromise in sonic perfor- mance with this circuit, and it en- sures safe opera- tion of the ampli- fier under even the most extreme oper- ating conditions. The different types of protection cir- cuits incorporated in the MC501 in- sure a long and safe operating life. This is just one of the many characteristics of McIntosh Power Amplifiers that make them world famous. The MC501 also includes the unique patented McIntosh Power Guard circuit. Power Guard eliminates the possibility of ever overdriving the amplifier into clipping. Refer to figures 18, 19 and 20. An overdriven amplifier can produce both audible and inaudible distortion levels exceeding 40%. The au- dible distortion is un- pleasant to hear, but the inaudible ultrasonic dis- tortion is also undesir- Figure 17 Figure 16 Figure 15