McIntosh MI347 Owner's Manual

McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: [phone] www.mcintoshlabs.com

MI347

Seven Channel

Power Amplier

Owner’s Manual

POWE R

MI 347 SE VE N CHA NN EL

PO WE R AMP LI FI ER

4

L C R 6 7

5

Important Safety Information is supplied in a separate document “Important Additional Operation Information Guide”

Thank You

With the MI347 Amplier, you have invested in a

precision instrument that will provide you with many
years of enjoyment. Please take a few moments to
familiarize yourself with the features and instructions
to get the maximum performance from your
equipment.

Please Take A Moment

The serial number, purchase date and McIntosh Dealer
name are important to you for possible insurance
claim or future service. The spaces below have been
provided for you to record that information:

Serial Number: _______________________________

Purchase Date: _______________________________

Dealer Name: ________________________________

Technical Assistance

If at any time you have questions about your McIntosh
product, contact your McIntosh Dealer who is familiar
with your equipment and many other brands that
may be part of your system. If you or your Dealer
wish additional help concerning a suspected problem,
you can receive technical assistance for all McIntosh
products at:
McIntosh Laboratory, Inc.

2 Chambers Street
Binghamton, New York 13903
Phone: [phone]
Fax: [phone]

Copyright 2020 © by McIntosh Laboratory, Inc.

Customer Service

If it is determined that this unit is in need of repair,
you can return it to your Dealer. You can also return it
to the McIntosh Laboratory Service Department. For
assistance on factory repair return procedure, contact
the McIntosh Service Department at:
McIntosh Laboratory, Inc.

2 Chambers Street
Binghamton, New York 13903
Phone: [phone]
Fa x : 607-723-1917

Table of Contents

Safety Instructions ..................................................... 2

(Separate Sheet) ................... Important Additional

Operation Information Guide

Thank You and Please Take a Moment ....................... 2

Technical Assistance and Customer Service .............. 2

Table of Contents ........................................................ 2

General Information ................................................... 2

Connector and Cable Information ..............................3

Introduction .................................................................3

Performance Features .................................................3

Dimensions .................................................................4

Installation ..................................................................5

Rear Panel Connections, Switches and Selection ....... 6

Output Terminals and How to Connect ................... 7-8

How to Operate ........................................................... 8

Front Panel Displays and Push-button ........................9

Specifications ............................................................ 10

Packing Instructions ................................................. 11

General Information

1. For additional connection information, refer to the
owner’s manual(s) for any component(s) connected
to the MI347.

2. The MI347 mutes the speaker output for
approximately two seconds when first turned on.

3. Included with the MI347 and located in the
Owner’s Manual Packet are two Side Rack
Mounted Brackets and screw fasteners. Refer to
page 5 for installing the Side Rack Mount Brackets.

MI347 SEVEN CHANN EL

POWER AMPL IFIER

45L C R 6 7

MI347 with Side Rack Mount Brackets installed

POWER

4. For the best performance and safety it is important
to attach no more thana single Loudspeaker with
an 8 Ohm or 4 Ohm impedance to the Channel
1 - Channel 7 output terminals. Refer to “How to
Connect” pages 8 thru 13.

Note: The impedance of a Loudspeaker actually

varies as the Loudspeaker reproduces different
frequencies. As a result, the nominal impedance
rating of the Loudspeaker (usually measured
at a midrange frequency) might not always
agree with the impedance of the Loudspeaker
at low frequencies where the greatest amount
of power is required. Contact the Loudspeaker
Manufacturer for additional information about
the actual impedance of the Loudspeaker before

connecting it to this Power Amplifier.

5. In the event that any one or more of the channels
overheat, due to improper ventilation or
Loudspeaker Impedance, the protection circuits
will activate. The Front Panel Channel LED will
change color and the audio will be muted. Refer
to page 9. When the MI347 has returned to a
safe operating temperature, Channel(s) normal
operation will resume.

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General Information, con’t, and Cable Information, Introduction and Performance Features

6. For additional information on the MI347 and
other McIntosh Products please visit the McIntosh
Website at www.mcintoshlabs.com.

Connector and Cable Information

XLR Connectors

Below is the Pin configuration for the XLR Balanced
Input, Input/Output Connectors on the MI347. Refer to
the diagram for connection:
PIN 1: Shield/Ground
PIN 2: + Input/Output
PIN 3: - Input/Output

Power Control Connector

The MI347 Power Control Input receives an On/Off
signal from +5 to +12 volts. The Power Control Output
will in turn provide a +12 volt Output Signal with a
total current up to 50mA. An additional connection
is for controlling the illumination
of the MI347 Meter Power Output
Indicators. The 3.5mm stereo mini
phone plug connects to a McIntosh
Preamplifier or A/V Control Center
Power Control Output.

Output Terminal Connector

When cables with spade lugs are used
for Loudspeaker Connection, the spade
lugs need an opening of at least 3/10 inch
(7. 6 m m)

PIN 2 PIN 1

PIN 3

Power
Control

Meter
Illumination
Control

Ground

3/10 of an inch
(7.6mm)

Introduction

Now you can take advantage of traditional McIntosh
standards of excellence in the MI347 Power Amplifier.
The Seven Channel Power Amplifier produces high
power output per channel and will drive quality
Loudspeakers to a high level of performance. The
MI347 reproduction is sonically transparent and
absolutely accurate. The McIntosh Sound is “The
Sound of the Music Itself.”

Performance Features

• Power Output

The MI347 consists of Seven Channel Power
Amplifier. Four Channels are rated at 125 watts with 8
ohms Loudspeakers and the three other Channels are
rated at 250 watts with 8 ohms Loudspeakers
The MI347 has been engineered for Home Theater
applications. This is why three channels, which are
intended to power the Left and Right Front Speakers
and the Center speaker, have twice the power as the
other four. (Pay attention to keeping the channels
straight!) The remaining channels are gain matched
for seamless multichannel integration.

•Power Guard

The McIntosh Power Guard® Circuit prevents the
amplifier from being over driven into clipping, with its
harsh distorted sound that can damage your valuable
Loudspeakers.

• Versatile Operation

The MI347 can provide power amplification for seven
channels in a single Zone A/V System or multiple in a
multiple channels for each of a Zone A/V System.

®

all seven Power Amplifier Input Channels.

• Sentry Monitor and Thermal Protection

McIntosh Sentry Monitor power output stage
protection circuits ensure the MI347 will have a long
and trouble free operating life. Built-in Thermal
Protection circuits guard against overheating.

• Power Control

The McIntosh Power Control Circuit allows for
remote turn-on of the MI347 Power Amplifier from
a McIntosh A/V Control Center or Preamplifier for a
single or dual Zone System.

• Engineered Power Supply

A regulated Power Supply ensures stable operation
despite power line variations.

• LED Solid State Front Panel Illumination

Front Panel Illumination is accomplished by extra long
life Light Emitting Diodes (LEDs). The Metal and
Glass Front Panel ensures the pristine beauty of the
MI347 will be retained for many years.

• Balanced, Unbalanced and Bus Inputs

There are Balanced and Unbalanced Connections for

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Dimensions

Rear View of the MI347

Front View of the MI347

17-

1/2

"

44.5cm

5-

7/32

"

13.3cm

6-

1/16

"

15.4cm

.25"

.64cm

2.0"

5.0cm

13-

21/32

"

34.7cm

1-

5/16

"

3.4cm

3/16

"

.5cm

5"

12.7cm

Front View of the MI347 with Side Mount Brackets

19"

48.3cm

16-

1/2

"

41.9cm

Side View of the MI347

18-

1/2

"

47.0cm

17-

1/16

"

43.3cm

MI347 SEVEN CHAN NEL

POWE R AMP LIFIE R

POWER

MI347 SEVEN CHAN NEL

POWE R AMP LIFIE R

POWER

45L C R 6 7

45L C R 6 7

CLASS 2 WIRING

CHANNEL 7-RB CHANNEL 6-RS CHANNEL 5-LS CHANNEL 4-LB CHANNEL 3-RF CHANNEL 2-C CHANNEL 1-LF

MI347 SEVEN CHANNEL POWER AMPLIFIER

McINTOSH LABORATORY, INC.,

BINGHAMTON, NY

HANDCRAFTED IN USA WITH US AND IMPORTED PARTS

50/60Hz 10A

100V-240V

FUSE

PUSH

15AH 250V

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

ATTENTION:

RISQUE DE CHOC ELECTRIQUE-NE PAS OUVRIR

SERIAL

NUMBER

POWER

CONTROL

IN

OUT

BAL BAL

UNBAL

+

–

UNBAL

+

–

BAL

UNBAL

+

–

UNBAL

+

–

BALBAL BAL

UNBAL

+

–

UNBAL

+

–

BAL

UNBAL

+

–

The following unit dimensions may be helpful in
determining the best location for your MI347.

Dimensions

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