McIntosh C4 Owners Manual serial 6600

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- 1- INSTRUCTION MANUAL MclNTOSH MODEL C-4 and C-4P AUDIO COMPENSATORS The Mcintosh Audio Compensator is a complete control unit for professional or home entertain­ ment systems. The Audio Compensator supplies the necessary gain and equalization for use with low level phonograph cartridges as well as the high output of radio tuners. Power Source Output Input Sensitivity and Impedance Frequency Response Harmonic Distortion Hum and Noise Level Size Weight ELECTRICAL AND MECHANICAL SPECIFICATIONS C-4: Any Mcintosh power amplifier C-4P: Self-Powered Main: 2.5 volts with rated input Tape: 0.5 volts with rated input Tape and Tuner: 0.5 V., 500 K. Mic: 5MV, 100K Phono 1: 5MV, 100K Phono 2: 5MV, variable 6.8K-52K See Graphs Less than 0.3% at 2.5 volts output, 20-20,000 cycles Tape and Tuner: Better than 80 db below output Mic and Phono: Less than 2 microvolts at input terminals (- 115dbm) C-4 and C-4P: 101/8" x 39/16" x 7½" Front Panel: 11" x 4¼" (Knobs project ¾") D8A: 6"x47/8"x2¼" (Power supply section of C-8P) C-4: 8 lbs. C-4P: 11 lbs., 6oz. FRONT PANEL CONTROLS INPUTS CONTROL AFFECTED Selector All Volume All Bass and Treble Tone All Compensation Switch Phono PURPOSE Select desired sound source. Control sound level. Continuously variable control of low and high frequencies. Provide frequency compensation for phonograph recordings or tape heads.

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- 2 - INSTALLATION OF MODEL C-4 and C-4P AUDIO COMPENSATORS The C-4 or C-4P may be used in its own cabinet or may be easily mounted in any equipment cabinet by using the mounting templates supplied with this manual. After these units have been secured in their desired location, proceed as follows: 1. Connect speaker to output of power amplifier. 2. Insert power amplifier line cord into one of the Auxiliary A. C. receptacles 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. Adjust gain control fully counterclockwise with MC-30 or MC-60. CAUTION: THE INTER-UNIT CABLE MUST NOT BE REMOVED FROM THE C-4. C-4P: Insert cable of D-8A power supply into the octal socket on the C-4P. Connect audio cable pro­ vided 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. Adjust gain control fully counterclock­ wise with MC-30 or MC-60.) 4. The Audio Compensator output is 2.5 volts with rated input signal and the power amplifier should be adjusted for this input sensitivity. However, any amplifier requiring less than 2.5 volts input may be used since the volume control on the Audio Compensator is located at the output. Reducing this control will not increase either the distortion or noise level. 5. Turn the volume control on the Audio Compensator to "OFF." 6. Insert power cord of the Audio Compensator into a 117 V.A.C. power outlet. 7. 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." 8. 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. This adjustment will occur at one end of rotation. The C-4 and C-4P have a D. C. supply for the tube heaters and minimum hum will be achieved when the correct side of this supply is grounded. 9. Turn the volume control on the Audio Compensator to off. 10. Insert inputs in their proper jacks at the back of the Audio Compensator, 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 Compensator are -115 DBM, or less than 2 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 recommenda­ tions as a guide to installation: 1. Connect inputs of Audio Compensator as outlined on the table below: INPUT (FOR INPUT CHANNEL 2.5V OUTPUT) GAIN IMPEDANCE USE TAPE AND TUNER 0.5V 15db 500K MIC 5MV 53db 100K PHONO 1 5MV 53db 100K Variable PHONO 2 5MV 53db 6.8K-52K Radio or TV Tuners. Tape recorders with self-contained equal­ izers. Low impedance microphone in conjunction with an input trans­former such as Mcintosh M-107. Magnetic phonograph cartridges. Tape recorder without self-contained equalizers (tape heads). Magnetic or constant amplitude phonograph cartridges. Tape heads.