User manual MCINTOSH MC502

[. . . ] THE MclNTOSH MC 502 POWER AMPLIFIER Reading Time: 28 Minutes Price $2. 00 VARIOUS REGULATORY AGENCIES REQUIRE THAT WE BRING THE FOLLOWING INFORMATION TO YOUR ATTENTION. PLEASE READ IT CAREFULLY. WARNING: TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS UNIT TO RAIN OR MOISTURE. The Mclntosh you have purchased is a Model MC 502. It has a serial number located on the rear panel of the chassis. Record that serial number here: Serial Number The model, serial number and purchase date are important to you for any future service. [. . . ] When using 8 ohm speakers and for the normally short distances of under 30 feet between the amplifier and speaker, No. For distances over 30 feet between the amplifier and speaker use larger diameter wire. Select the correct size wire for the wire length from the chart. It is recommended that the DC resistance of the speaker leads be less than 5% of the speaker impedance. Resistance of the leads should be computed for the length of wire both to and from the speaker or speakers. 4 For multiple speaker operation, run separate leads from the amplifier to the speakers. CONNECTING LOUDSPEAKERS FOR STEREO Connect the leads from the left loudspeaker to the Left and Common OUTPUT terminals on the MC 502. Connect the leads from the right main loudspeaker to the Right and Common terminals. CONNECTING ONE LOUDSPEAKER FOR MONO Connect leads from the loudspeaker to the Left and Right OUTPUT terminals on the MC 502. Check to be sure the MODE switch is in the MONO position. In MONO operation neither output terminal (Left or Right) is at ground potential. Due precaution is required when connecting test instruments since neither terminal can be grounded. AC POWER The amplifier AC power cord is plugged into a 120 volt 50/60 Hz wall outlet. FUSE A 4-amp fuse protects the MC 502 circuits. The fuse does not protect additional equipment connected to the rear panel AC power outlets. Stereophonic Connections PROGRAM SOURCE RIGHT SPEAKER STEREO MONO LEFT SPEAKER MODE PLACE SWITCH IN STEREO POSITION FOR STEREO OPERATION Monophonic Connections PROGRAM SOURCE MODE STEREO MONO SPEAKER PLACE SWITCH IN STEREO POSITION FOR STEREO OPERATION Front Panel Controls and How to Use Them LEFT GAIN Use the left gain control to adjust the volume in the left channel to the desired listening level. Turn the control clockwise to increase the volume. RIGHT/MONO GAIN Use the right/mono gain control to adjust the volume in the right channel to the desired listening level. Turn the control clockwise to increase the volume. When the MC 502 is connected for monophonic operation and the rear panel Mode Switch in Mono the volume is controlled by the Right/Mono Gain control only. HEADPHONES The output of the front panel HEADPHONE jack has been designed to feed low impedance dynamic stereo headphones. Plug dynamic headphones into the front panel HEADPHONE jack. Adjust the front panel LEFT GAIN and RIGHT/MONO GAIN control for comfortable headphone listening. Electrostatic headphones generally require higher power than dynamic headphones. Connect them to the LEFT and RIGHT OUTPUT contacts on the back of the MC 502. SPEAKERS OFF: The loudspeakers are turned off when the SPEAKER switch is in the OFF position. [. . . ] The MC 502 has a built-in waveform comparator which compares the wave shape of the output signal to the input signal. If the disparity between the two signals exceeds 0. 5% (equivalent to 0. 5% total harmonic distortion) a red limit indicator illuminates. With any further increase in distortion the Power Guard circuit will operate. This circuit limits the input dynamically so that the amplifier cannot be overdriven. [. . . ]