McIntosh ML 4C Service Manual

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SPECIFICATIONS

SPEAKER SIZE
Woofers four l2" dia. frame size (l0 dia. radiators)
Low mid-range 8 dia. frame size (5 dia. radiator)
Mid mid-ranges two i-l/Z dia. dome radiators

High mid-ranges two l-I/Zll dia. dome radiators
Tweeters two l-5/8 dia. coaxial super radiators

CROSSOVER FREQUENCIES
ZSOHZ, I.5kHz, 3kHz, 5 7kHz

IMPEDANCE

8n Nominal

POWER HANDLING: Sine wave steady state

SlNE WAVE
POWER
LIMIT

IN WATTS

20 250 IK L5K 7K 20K

FREQUENCY IN H1

Avoid operating the speaker system with sustained sine wave signals at power levels
greater than the indicated limits. Permanent damage may result.

POWER HANDLING: Program Material

High energy peaks normal to orchestral music are easily and faithfully reproduced
by the speaker system. These peaks are of relatively short duration and do not
produce the heating effect caused by sustained tone operation. The ML-h speaker
system will handle up to 300 watts of orchestral music program material. Care
must be taken. however, to use a power amplifier that has an adequate power rating.
If a low power amplifier is used, the loudest passages may be clipped by the
amplifier. This clipping will cause the speaker to Sound distorted. The large
harmonic content of a badly clippedH signal can cause excessive heating and re-
sulting damage to the high frequency speaker elements and crossover network.

OUTPUT LEVEL

In a reverberant room the system will nominally produce an 89dB sound pressure
level when driven at a one watt level referred to 89.

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SERVICE BULLETIN

REPLACEMENT OF 8 LOUDSPEAKER 036-002

MODEL: ML-AC and ML-AM Loudspeakers.
PURPOSE OF MODIFICATION: To maintain the same acoustic output.

WHAT UNITS ARE AFFECTED: ML-RC Serial NO. LlEOOl through LlEl89.
ML-AM Serial No. LlFOOl through LIFOSZ.

WHEN MODIFICATION SHOULD BE MADE: When replacing defective 036-002
8 loudspeaker.

McINTOSH MODIFICATION KIT: No kit available.

PARTS REQUIRED:

QUANTITY PART NUMBER DESCRIPTION
l l39-090 Wirewound Resistor: 7.59, low
I 036-025 8 Loudspeaker
PROCEDURE:

Step l Remove rear panel.

Step 2 Locate lOn, lO watt resistor in series with the 8
loudspeaker. Remove and replace with 7.59, lo watt
resistor.

Step 3 Replace rear panel.

(over)

McIntosh Laboratory Incorporated 2 Chambers Street Binghamtun, New York 13903 Phone: Area Code 607-723-3512