User manual MCINTOSH MAC4100

[. . . ] THE MCINTOSH MAC 4100 RECEIVER Reading Time: 48 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 MAC 4100. 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. [. . . ] Logging Scale - 0-100 As the tuning knob is turned, the tuning indicator moves across the dial. To make tuning easier only the portion of the indicator directly behind the appropriate dial scale is lighted. On FM, the upper portion of the indicator is lighted. The logging scale can be used to accurately retune any station. You may find it easier to keep a record of your favorite stations by use of the logging scale. SIGNAL STRENGTH METER When tuning either an FM or AM signal the signal strength meter indicates the strength of the signal as received from the antenna. The higher the indication the stronger the signal. AMPLIFIER POWER OUTPUT INDICATORS FM TUNING METER An FM station is correctly tuned when the meter needle is in the black area of the FM tuning meter and the AFL indicator light is lighted. 12 The amplifier POWER output indicators are to the left of the tuning dial. There are two vertical columns of seven yellow Light Emitting Diode [LED] indicators - the left column for the left channel and right column forthe right channel. As power to the loudspeakers is increased, more LEDs are turned on, vertically, indicating the increase. The LEDs provide constant and instant information on the amount of power being fed to your speakers. POWER GUARD POWER GUARD assures that the amplifier can not be over driven so amplifier output clipping is eliminated. Clipping is caused when the amplifier is asked to produce more power output than it can deliver with low distortion. Amplifiers are capable of delivering large quantities of power when they are driven to clipping and can have more than 40% harmonic distortion. The extra energy content of the clipped signal will damage most speakers. A Mclntosh advancement helps to protect your speaker from this kind of damage. The MAC 4100 has a built in "waveform comparator" that compares the wave shape of the input signal with the output signal. If the non-linearity between the two signals exceeds 0. 5% the POWER GUARD circuit operates. Operation is indicated when the LEDs at the top of the amplifier power indicator are lighted in red. As long as the amplifier operates without overload the NORMAL indicator illuminates. With POWER GUARD operating the output waveform distortion is limited to 1 %. INPUT INDICATORS At the bottom right of the tuning dial area are eight LEDs, six indicate the status of the INPUT SELECTOR switch. The illuminated LED indicates the program source selected. The two remaining LEDs indicate AFL and FM MPX. AFL indicates the operation of the automatic frequency lock circuit showing that the tuner is correctly tuned to the center frequency of the FM station. FM MPX - indicates the FM station is broadcasting a 19 kHz pilot signal necessary for the transmission of FM stereo programs. It denotes the station is broadcasting stereo. Balancing Your Stereo The performance and enjoyment of a stereo system is greatly increased when the sound is properly balanced. [. . . ] A heavy duty relay, timecontrolled by a transistor switch, connects the output to the speakers. The control to the transistor switch is derived from a long time constant capacitor charging network that turns the relay on approximately two seconds after the power switch is turned on. The same circuit has a short turnoff time constant and the relay drops out before the receiver's main power supply has a chance to discharge. POWER SUPPLY Amplifiers are capable of delivering large quantities of power when they are driven to clipping. Clipping is caused when the amplifier is asked to produce more power output than it can deliver with low distortion. [. . . ]