McIntosh C-8 Owners manual

INSTRUCTION MANUAL

MclNTOSH MODEL C-8 and C-8P

AUDIO COMPENSATORS

McINTOSH LABORATORY, INC.

320 Water St. Binghamton, N. Y.

U.S.A.

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INSTRUCTION MANUAL

McINTOSH MODEL C-8 and C-8P

AUDIO COMPENSATORS

The McIntosh Audio Compensator is a complete control unit for professional
or home entertainment systems. The Model C-8 derives its power from any
McIntosh power amplifier: the Model C-8P is self-powered.

Five input channels are provided: three which produce constant amplifica­tion over the audio spectrum of 20-20, 000 cycles, and two which are equalized for
magnetic phonograph cartridges.

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-8 and C-8P,

AUDIO COMPENSATORS

The C-8 and C-8P Audio Compensator may be mounted in any type equip­ment 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. Cut a rectangular hole in the panel to be used for mounting, insert the
Audio Compensator, and secure with wood or machine screws. Mounting tem-

plates are provided with this manual for the C-8 and C-8P.

When installing the C-8P, the power supply section should be mounted at

least two feet from the Audio Compensator.

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.

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3. C-8: 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-8.

C-8P: Insert cable of D-8 power supply into socket labeled "INTER­UNIT CABLE" on C-8P. Connect audio cable provided between

RETMA pin jack labeled "MAIN OUTPUT" on C-8P and 2.5V input

of power amplifier. (Socket labeled "PRE-AMP INPUT" on McIntosh

power amplifiers.)

4. The Audio Compensator delivers 2.5 volts of audio signal at full
output. The gain control of the power amplifier should be

adjusted as outlined in the amplifier instruction manual for this
sensitivity.

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 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-8: Adjust the hum reducing potentiometer on the power
amplifier for minimum hum.

C-8P: 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
Compensator, and all A.C. power cords into the A.C. outlets
provided.

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INPUT CONNECTING PROCEDURE

The inherent hum and noise voltages applied to the input of the Audio
Compensator 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

1 & 2

3

4

5

FOR USE WITH

AM-FM Tuners
Wire Reproducers

Tape Reproducers
Crystal or Ceramic

cartridges

Crystal Microphones
Low Impedance

Microphone

High level Magnetic
cartridges. (Termi-

nated for Pickering

cartridge)

Low level magnetic

cartridges or ampli­tude responsive
cartridges such as
FM or ceramic

(FOR 2.5 V. OUTPUT)

INPUT

MIN. MAX.

70 MV. 20 V.

10 MV. 1 V.

30 MV. 150 MV.

10 MV. 50 MV.

GAIN

32 db

50 db

40 db

50 db

REMARKS

Input levels in excess
of .07V should be re-

duced by potentiometers
on back panel.

Input levels in excess
of 10 MV should be
reduced by potentiom­eter on back panel.

See text for operation

of these channels.

The Audio Compensator and magnetic phonograph cartridges should
be mounted at least two feet from power transformers.

Inter-unit cables provide a complete ground system. Alternate

ground wires create ground loops which will usually increase hum

level.