User manual MCINTOSH MC302

[. . . ] McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 www. mcintoshlabs. com MC302 Power Amplifier Owner's Manual The lightning flash with arrowhead, within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to persons. The exclamation point within an equilateral triangle is intended to alert the user to the presence of important operating and maintenance (servicing) instructions in the literature 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. 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. [. . . ] Refer to "General Information" Note 4 on page 3 for additional information. Note: The illustration on separate sheet "Mc1A"is connections for 8 (ohms) Loudspeakers. 9. Connect the MC302 power cord to an active AC outlet. WARNING: Loudspeaker terminals are hazardous live and present a risk of electric shock. For additional instruction on making Loudspeaker Connections contact your McIntosh Dealer or McIntosh Technical Support. 9 Caution: Do not connect the AC Power Cord to the MC302 Rear Panel until after the Loudspeaker Connections are made. Failure to observe this could result in Electric Shock. How to Connect for Bi-Amp The connection instructions below, together with the MC302 Connection Diagram located on the separate folded sheet "Mc1B", 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. For additional information refer to "Connector and Cable Information" on page 4. For Remote Power Control, connect a power control cable from the Audio Preamplifier or A/V Control Center Power Control Output 1 to the MC302 POWER CONTROL IN Amplifier One. Connect a power control cable from the Audio Preamplifier or A/V Control Center Power Control Output 2 to the MC302 POWER CONTROL IN Amplifier Two. Connect XLR cables from the Balanced Output 1 (L&R) of a Audio Preamplifier or A/V Control Center to the MC302 Balanced INput (RIGHT and LEFT) on Amplifier One. Place the INPUT MODE Switch in the BALANCED Position. Note: An optional hookup is to use unbalanced cables and place the INPUT MODE Switch in the UNBALANCED Position. This McIntosh MC302 Power Amplifier is designed for Loudspeakers with an impedance of 2 ohms, 4 ohms or 8 ohms. Connect a single Loudspeaker only to the Right and Left Output Terminals. When connecting Loudspeakers to the MC302 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: Loudspeaker Cable Distance vs Wire Gauge Guide Loudspeaker Impedance 2 Ohms 4 Ohms 8 Ohms 25 feet (7. 62 meters) or less 50 feet (15. 24 meters) or less 100 feet (30. 48 meters) or less 12AWG 14AWG 16AWG 10AWG 12AWG 14AWG 8AWG 10AWG 12AWG Banana Plugs are for use in the United States and Canada only: 6. Attach the previously prepared bare wire cable ends into the banana plugs and secure the connections. Refering to Figure B, connect the Figure A Loudspeaker hookup cables with banana plugs into the hole at the top of the terminal to the MC302 COM (Negative) Output Terminal A and Figure B Figure Positive Output Terminal indentified as 2 (ohms), 4 (ohms) or 8 (ohms) connection to match the impedance of the Loudspeaker, being careful to observe the correct polarities. If the Loudspeaker's impedance is in-between the available connections, use the nearest lower impedance connection. Refer to "General Information" Note 4 on page 3 for additional information. Note: The illustration on separate sheet "Mc1B"is connections for 8 (ohms) Loudspeakers. 5. Prepare the Loudspeaker Hookup Cables for attachment to the MC302 Power Amplifiers: Bare wire cable ends: Carefully remove sufficient insulation from the cable ends, refer to figures 2, 3 & 4. If the cable is stranded, carefully twist the strands together as tightly as possible. 4. Connect XLR cables from the Balanced Output 2 (L&R) of a Audio Preamplifier or A/V Control Center to the MC302 Balanced INput (RIGHT and LEFT) on Amplifier Two. Place the INPUT MODE Switch in the BALANCED Position. Note: An optional hookup is to use unbalanced cables and place the INPUT MODE Switch in the UNBALANCED Position. Figure 2 Figure 3 Figure 4 Notes: 1. [. . . ] Power Supply Circuits To compliment the design of the MC302 Power Amplifier Circuitry, there is a high current high voltage power supply for both channels. The very large Power Transfomer can supply over 13 amps of continuous current. Refer to figure 23 (golf ball is for size comparison). Block Diagram of the Power Supply LIGHTING CONTROL POWER CONTROL BACKUP POWER SUPPLY CONTROL LOGIC AC Power Socket INRUSH CURRENT LIMITER MAIN RELAYS Figure 23 It is enclosed in the legendary McIntosh Potted Enclosures and weighs 28lbs. The two super size main filter capacitors can store over 140 Joules of energy for both amplifier channels, necessary for the wide dynamic range that "Digital Audio" demands. [. . . ]