User manual MCINTOSH MC252

[. . . ] Power Amplifier MC252 Owner's Manual McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 FAX: 607-724-0549 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. 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. 1. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus (including amplifiers) that produce heat. [. . . ] If the Mono Bi-Amp (Parallel) Mode is appropriate for the Loudspeakers, proceed to page 12 for proper connections. For Remote Power Control, connect a power control cable from the Control Center or Preamplifier Power Control Out to the MC252 Power Control In. Connect cables from the Unbalanced Output of a McIntosh Preamplifier or Control Center to the MC252 Unbalanced R/MONO Input. Note: An optional hookup is to use balanced cables. Banana plug connection: Insert the banana plug into the hole at the top of the terminal. Tighten the top portion of the terminal post and the set screw to secure the banana plug in place. Refer to figures 7 and 8. Note: The use of Banana Plugs is for use in the United States and Canada only. 4. Referring to the "Mono Bridge Hookup Connections" Chart on the next page, connect the Loudspeaker hookup cables to appropriate output terminals based on the impedance of the Loudspeaker (4S [ohm], 8S [ohm] or 16S [ohm]), being careful to observe the correct polarities. If the Loudspeaker's impedance is inbetween the available connections, use the nearest lower impedance connection. 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. 3. Prepare the Loudspeaker Hookup Cables that attach to the MC252 Power Amplifier by choosing one of the methods below: Bare wire cable ends: Carefully remove sufficient insulation from the cable ends, refer to figures 1, 2 & 3. If the cable is stranded, carefully twist the strands together as tightly as possible. Note: If desired, the twisted ends can be tinned with solder to keep the strands together, or attach spade lug and/or banana connector. 5. Attach the supplied Terminal Connection Covers with the four Mounting Screws (6-32 x 1/4 inch Phillips Head) to the Rear Panel of the MC252 Amplifier. Refer to figure 9. Note: The illustration in figure 9 is for the purpose of installing the Terminal Connection Covers, showing the opening on the covers for the Loudspeaker Cables to exit the MC252. Connect the MC252 power cord to an active AC outlet. Terminal Connection Covers Spade lug or prepared wire connection: Insert the spade lug connector or prepared section of the cable end into the terminal side access hole, and tighten the terminal cap until the cable is firmly clamped into the terminal so the wires cannot slip out. Refer to figures 4, 5 & 6. Cable Openings Cover Mounting Screw Locations Figure 9 10 Cover Mounting Screw Location How to Connect in Mono Bridged Mode McIntosh C45 Audio Control Center MC252 Top Rear View To AC Outlet Mono Bridge Hookup Connections Loudspeaker Loudspeaker Negative Impedance (-) Connection 4S (Ohm) 4 ohm Loudspeaker Loudspeaker Positive (+) Connection Right Output 2S Positive (+ ) Connection Right Output 4S Positive (+ ) Connection Right Output 8S Positive (+) Connection Left Output 2S Positive (+ ) Connection Left Output 4S Positive (+ ) Connection Left Output 8S Positive (+ ) Connection 8S (Ohm) 16S (Ohm) 11 How to Connect in Mono Bi-Amp (Parallel) Mode Caution: The supplied AC Power Cord should not be connected to the Rear Panel of the MC252 Amplifier until after the Loudspeaker Connections have been made and the supplied protective Terminal Connection Covers have been installed. Failure to observe this could result in Electric Shock. There are two different ways of operating the MC252 monaurally, Mono Bridged Mode and Mono Bi-Amp (Parallel) Mode. The Mono Bridge Mode allows for Loudspeakers of 4S (ohm), 8S (ohm) or 16S (ohm) impedance to be connected to the MC252. The Mono Bi-Amp (Parallel) Mode allows for Loudspeakers of 1S (ohm), 2S (ohm) or 4S (ohm) impedance to be connected to the MC252. Choose the appropriate Mono Mode determined by the impedance of your Loudspeakers. If the Mono Bridge Mode is appropriate for the Loudspeakers, proceed to page 10 for proper connections. For Remote Power Control, connect a power control cable from the Control Center or Preamplifier Power Control Out to the MC252 Power Control In. Connect cables from the Unbalanced Output of a McIntosh Preamplifier or Control Center to the MC252 R/MONO Unbalanced Input. Note: An optional hookup is to use balanced cables. Banana plug connection: Insert the banana plug into the hole at the top of the terminal. Tighten the top portion of the terminal post and the set screw to secure the banana plug in place. [. . . ] The audible distortion is Figure 17 unpleasant to hear, but the inaudible ultraWithout Power Guard sonic distortion is also undesirable, since it can damage valuable loudspeaker system tweeters. You will never experience the harsh and damaging distortion due to clipping. The Power Guard circuit is a waveform comparator, monitoring both the input and output waveforms. Figure 18 Under normal operating conditions, there With Power Guard are no differences between the shape of these waveforms. [. . . ]