McIntosh MC275 User Manual

Stereo Power Amplifier

MC275

Owner’s Manual

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

The lightning flash with arrowhead,
within an equilateral triangle, is intended
to alert the user to the presence of
uninsulated “dangerous voltage” within
the product’s enclosure that may be of
sufficient magnitude to constitute a risk
of electric shock to persons.

The exclamation point within an equi­lateral triangle is intended to alert the
user to the presence of important
operating and maintenance (servic­ing) instructions in the literature ac­companying the appliance.

WARNING - TO REDUCE RISK OF

FIRE OR ELECTRICAL SHOCK, DO

NOT EXPOSE THIS EQUIPMENT TO

RAIN OR MOISTURE.

IMPORTANT SAFETY

INSTRUCTIONS!

PLEASE READ THEM BEFORE

OPERATING THIS EQUIPMENT.

1. Read these instructions.

2. Keep these instructions.

3. Heed all warnings.

4. Follow all instructions.

5. Do not use this apparatus near water.

6. Clean only with a dry cloth.

7. Do not block any ventilation openings. Install in
accordance with the manufacturer’s instructions.

8. Do not install near any heat sources such as
radiators, heat registers, stoves, or other
apparatus (including amplifiers) that produce
heat.

9. Do not defeat the safety purpose of the polarized
or grounding-type plug. A polarized plug has two
blades with one wider than the other. A grounding
type plug has two blades and a third grounding
prong. The wide blade or the third prong are
provided for your safety. If the provided plug
does not fit into your outlet, consult an electrician
for replacement of the obsolete outlet.

10. Protect the power cord from being walked on or
pinched particularly at plugs, convenience
receptacles, and the point where they exit from
the apparatus.

NO USER-SERVICEABLE PARTS

INSIDE. REFER SERVICING TO

QUALIFIED PERSONNEL.

To prevent the risk of electric shock, do not remove cover or

back. No user serviceable parts inside.

11. Only use attachments/accessories specified by the
manufacturer.

12. Use only with the cart, stand, tripod, bracket, or
table specified by the manufacturer,
or sold with the apparatus. When a
cart is used, use caution when moving
the cart/apparatus combination to
avoid injury from tip-over.

13. Unplug this apparatus during lightning storms or
when unused for long periods of time.

14. Refer all servicing to qualified service personnel.
Servicing is required when the apparatus has
been damaged in any way, such as power-supply
cord or plug is damaged, liquid has been spilled
or objects have fallen into the apparatus, the
apparatus has been exposed to rain or moisture,
does not operate normally, or has been dropped.

15. Do not expose this equipment to dripping or
splashing and ensure that no objects filled with
liquids, such as vases, are placed on the
equipment.

16. To completely disconnect this equipment from
the a.c. mains, disconnect the power supply cord
plug from the a.c. receptacle.

17. The mains plug of the power supply cord shall
remain readily operable.

2

Thank Y ou

Table of Contents

Your decision to own this McIntosh MC275 Stereo Power
Amplifier ranks you at the very top among discriminating
music listeners. You now have “The Best.” The McIntosh
dedication to “Quality,” is assurance that you will receive
many years of musical enjoyment from this unit.

Please take a short time to read the information in this
manual. We want you to be as familiar as possible with all
the features and functions of your new McIntosh.

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:

T echnical Assistance

If at any time you have questions about your McIntosh
product, contact your McIntosh Dealer who is familiar with
your McIntosh equipment and any 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:

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

Thank You and Please Take a Moment............................. 3

Technical Assistance and Customer Service .................... 3

Table of Contents.............................................................. 3

Important Information ...................................................... 4

Connector Information ..................................................... 4

Introduction ...................................................................... 4

Performance Features ....................................................... 4

Dimensions ....................................................................... 5

Installation of Tubes and Tube Cover............................... 6

Location and Ventilation................................................... 7

Left Side Panel Connections ............................................ 8

Right Side Panel Connection and Fuse Holder ................ 9

How to Connect for Stereo ............................................. 10

How to Connect for Mono Parallel ................................ 11

Left Side Panel Controls and Switches .......................... 12

How to Operate............................................................... 13

Specifications ................................................................. 14

Packing Instructions ....................................................... 15

McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, New York 13903
Phone: [phone]
Fax: [phone]

Customer Service

If it is determined that your McIntosh product 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]
Fax: [phone]

Copyright 2004 © by McIntosh Laboratory, Inc.

3

Introduction and Performance Features

Important Information

1. Caution: To prevent electrical shock make sure that the AC
POWER CORD IS NOT CONNECTED TO THE
MC275 when inserting or removing Vacuum Tubes,
as there are hazardous voltages present at the pins of
the Tube Sockets.

2. When Vacuum Tubes are installed or removed make sure to
reattach the Tube Cover to the MC275 Chassis.

3. If the MC275 has been On, please allow the Hot Vacuum
Tubes to cool first before removing them.

4. For additional connection information, refer to the owner’s
manual(s) for any component(s) connected to the MC275.

5. It is very important that loudspeaker cables of adequate size
be used, so that there will be minimum power loss. The size is
specified in Gauge Numbers or AWG (American Wire Gauge).
The smaller the Gauge number, the larger the wire size.
Connection Terminals will accept up to a 8 AWG wire size:

If your loudspeaker cables are 50 feet (38.1m) or less,
use at least 14 Gauge.
If your loudspeaker cables are 100 feet (76.2m) or less,
use at least 12 Gauge.

Connector Information

XLR Connectors

Below is the Pin configuration for the XLR Balanced Input
Connectors on the MC275. Refer to the diagram for con­nection:

PIN 1: Shield/Ground
PIN 2: + Input
PIN 3: - Input

Pin 2
Pin 1
Pin 3

Introduction

Now you can take advantage of traditional McIntosh stan­dards of excellence in the MC275 Stereo Power Amplifier.
Two 75 watt output channels will drive any high quality
Loudspeaker System to its ultimate performance. The
MC275 reproduction is sonically transparent and abso­lutely accurate. The McIntosh Sound is “The Sound of the
Music Itself.”

Performance Features

••

• Power Output

••

The MC275 consists of two separate power amplifier chan­nels, each capable of 75 watts into 4, 8 or 16 ohm Loud­speakers in stereo. It may also be operated in mono at 150
watts into 2, 4, or 8 ohm Loudspeakers.

••

• Bifilar Wound Transformers and Output Circuit

••

The Power Output Sections utilize the famous McIntosh
Patented Unity Coupled Circuit with a Bifilar Wound Out­put Transformer for low distortion, extended frequency re­sponse and cool operating output tubes.

••

• Balanced and Unbalanced Inputs

••

Balanced connections guard against induced noise and al­low long cable runs without compromising sound quality.

••

• Gold Plated Connectors and Tube Socket Contacts

••

Gold Plated Input Jacks and Output Binding Posts provide
trouble free connections. Ceramic tube sockets with gold
plated contacts provide protection from atmospheric con­tamination. Output Tube Sockets include Air-Pipe cooling
at their bases.

••

• Super Mirror Chassis Finish

••

The famous McIntosh Stainless Steel Chassis with Super
Mirror Finish ensures the pristine beauty of the MC275
will be retained for many years.

4

MC275 Dimensions

The following dimensions can assist in determining the
best location for your MC275. There is additional informa­tion on page 7 pertaining to installing the MC275 into cabi­nets.

Front View of the MC275

1

-3/4

"

4.45cm

16-1/2

41.91cm

13

-5/8

34.61cm

MC275 Dimensions

"

-7/8

"

7

20.00cm

"

8

-1/4

"

20.96cm

Top View of the MC275

Left Side View
of the MC275

1

-3/4

"

4.45cm

4

-3/8

"

11.11cm

5

-9/16

"

14.13cm

12"

30.48cm

Right Side View
of the MC275

1

-1/4

"

3.18cm

5