McIntosh C4 C4 P Owners Manual

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INSTRUCTION MANUAL McINTOSH MODEL C-4 and C-4P AUDIO COMPENSATORS The McIntosh Audio Compensator is a complete control unit for profes- sional or home entertainment systems. The Model C-4 derives its power from any McIntosh power amplifier; the Model C-4P is self-powered. Five input channels are provided, three of which produce constant ampli- fication over the audio spectrum of 20-20, 000 cycles, one which is compensated for magnetic phonograph cartridges and one which is compensated for either magnetic or constant amplitude cartridges. Each input is equipped with a level control. A three output system is employed, two main outputs where all con- trols are effective and one tape output where only the channel selector and com- pensation selector are effective. THE AUDIO COMPENSATOR IS A COMPLETE PRE-AMPLIFIER AND RECORD COMPENSATOR: THEREFORE, THE USE OF AN AUXILIARY EQUALIZER OR PRE-AMPLIFIER WITH THIS UNIT IS NOT RECOMMENDED. INSTALLATION OF MODEL C-4 and C-4P AUDIO COMPENSATORS The C-4 and C-4P Audio Compensator may be mounted in any type equip- ment cabinet, relay rack panel, door, wall, etc., or in its own cabinet for chair side operation. It is not necessary to disassemble the Audio Compensator for mounting. Using the mounting templates provided with this manual, cut a rectangular hole in the panel to be used for mounting, insert the Audio Compen- sator and secure with wood or machine screws. When installing the C-4P, the power supply section should be mounted at least two feet from the Audio Compensator. After these units have been secured, proceed as follows: 1. Connect speaker to output of power amplifier. 2. Insert power amplifier line cord into one of the Auxiliary A.C. re- ceptacles provided at the rear chassis of the Audio Compensator. 3. C-4: Connect inter-unit cable to socket labeled "PRE-AMP INPUT" on McIntosh Power Amplifiers. CAUTION: THE INTER-UNIT CABLE MUST NOT BE REMOVED FROM THE C-4. C-4P: Insert cable of D-8 power supply into socket labeled "INTER-UNIT CABLE" on C-4P. Connect audio cable provided between RETMA pin jack labeled "MAIN OUTPUT" on C-4P and 2.5V input of power amplifier. (Socket labeled "PRE-AMP INPUT" on McIntosh power amplifiers.) - 1 -

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- 2 - 4. The Audio Compensator delivers 2. 5 volts of audio signal at full out- put. The gain control of the power amplifier should be adjusted as out- lined in the amplifier instruction manual for this sensitivity. (McIntosh Amplifier Models A-116, MC-30, MC-60, set gain control fully counter clockwise; 50W-2 and 20W-2 fully clockwise.) 5. Turn the volume control on the Audio Compensator to "OFF". 6. Insert power cord of the Audio Compensator into a 117V., 50/60 cycle power outlet. 7. Turn the Selector Switch on the Audio Compensator to "5" and Bass control fully clockwise. 8. Turn the volume control on the Audio Compensator clockwise until the power switch is activated. Allow thirty seconds for warm-up, then advance the volume control to "10". 9. C-4: Adjust the hum reducing potentiometer on the power amplifier for minimum hum. C-4P: Adjust the hum reducing potentiometer on the power supply for minimum hum. 10. Turn the volume control on the Audio Compensator to "OFF". 11. Insert inputs into their proper jacks at the back of the Audio Com- pensator, and all A.C. power cords into the A.C. outlets provided. INPUT CONNECTING PROCEDURE The inherent hum and noise voltages applied to the input of the Audio Com- pensator are -110 DBM, or less than 3 microvolts. To avoid lowering the signal to hum ratio of the Audio Compensator, by adding hum voltages to the input, extreme care must be taken in its installation. We offer the following recommendations as a guide to installation: 1. Connect inputs of Audio Compensator as outlined on the table below. CHANNEL TAPE AND TUNER MIC PHONO 1 AND PHONO 2 FOR USE WITH Radio or TV Tuners Tape Recorders Crystal or Ceramic cartridges Crystal Microphones Low Impedance Microphone Phonograph Cart- ridges (magnetic or constant amplitude) INPUT MIN. 60MV 3MV 3MV MAX. 20V 1V 1V GAIN 32db 52db 52db REMARKS Inputs in excess of the recom- mended minimum should be reduced by the level ad- justments located on the back panel. See text for com- plete operation. 2. The Audio Compensator and magnetic phonograph cartridges should be mounted at least two feet from power transformers. 3. Inter-unit cables provide a complete ground system. Alternate ground wires should not be used since they will produce ground loops and increase the hum level.