McIntosh MA2275 User Manual
Tube Integrated Amplifier
MA2275
Owner’s Manual
McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 FAX: 607-724-0549
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 You
Your decision to own this McIntosh MA2275 Tube Integrated 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:
Technical 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:
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, New York 13903
Phone: 607-723-1545
Fax: 607-723-3636
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: 607-723-3515
Fax: 607-723-1917
Copyright 2004 © by McIntosh Laboratory, Inc.
Table of Contents
Safety Instructions ............................................................ 2
Thank You and Please Take a Moment ............................. 3
Technical Assistance and Customer Service .................... 3
Table of Contents and Important Information .................. 3
Connector Information ..................................................... 4
Introduction ...................................................................... 4
Performance Features ....................................................... 4
Dimensions ....................................................................... 5
Installation of Tubes, Equipment Location
and Ventilation .................................................................. 6
Installation in a Custom Cabinet ...................................... 8
Top Panel Connections and Tube Locations .................... 9
Rear Panel Connections .................................................. 10
How to Connect Loudspeakers ....................................... 11
How to Connect Audio Components .............................. 12
How to Connect for a Second Room .............................. 13
Front Panel Controls, Displays, Push-Buttons
and Switch ...................................................................... 14
How to Operate............................................................... 15
Remote Control Push-Buttons ........................................ 18
How to Operate by Remote Control ............................... 19
Specifications ................................................................. 22
Packing Instruction ......................................................... 23
Important Information
1. Caution: To prevent electrical shock make sure the AC
POWER CORD IS NOT CONNECTED TO THE
MA2275 . Also do not touch the Vacuum Tube
Connection Pins when inserting or removing them,
as there may be hazardous voltages present at the
Tube Socket Pins even after the MA2275 has been
switched Off for a period of time.
2. When Vacuum Tubes are installed or removed, reattach the
Tube Cover with the Original Tube Cover Screws.
3. If the MA2275 has been On, please allow the Hot Vacuum
Tubes to cool first before removing them.
4. The following Connecting Cable is available from the
McIntosh Parts Department:
Data and Power Control Cable Part No. 170-202
Six foot, 2 conductor shielded, with two 1/8 inch stereo
mini phone plugs.
5. For additional connection information, refer to the owner’s
manual(s) for any component(s) connected to the MA2275.
6. 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.
3
Connector Information
Introduction and Performance Features
XLR Connectors
Below is the Pin configuration for the XLR Balanced Input
Connectors on the MA2275. Refer to the diagram for connection:
PIN 1: Shield/Ground
PIN 2: + Input
PIN 3: - Input
Power Control Connectors
The MA2275’s Power Control Outputs provide a 5 volt
signal. Use a 1/8 inch stereo mini
phone plug to connect to the
Power Control Input on other
McIntosh Components.
Data Port Connectors
The MA2275’s Data Port Output provides Remote Control
Signals. Use a 1/8 inch stereo
mini phone plug to connect to the
Data Port Inputs on McIntosh
Source Units.
Pin 2
Pin 1
Pin 3
Positive
N/C
Ground
Data Signal
N/C
Ground
Introduction
Now you can take advantage of traditional McIntosh standards of excellence in the MA2275 Tube Integrated Amplifier. The versatile Preamplifier together with two 75 watt
Power Amplifier Channels provide all the electronics necessary to drive any high quality Loudspeaker System. The
MA2275 reproduction is sonically transparent and absolutely accurate. The McIntosh Sound is “The Sound of the
Music Itself.”
Performance Features
••
• Power Output
••
The MA2275 has two separate power amplifier channels,
each capable of 75 watts into 2, 4 or 8 ohm Loudspeakers.
••
• Bifilar Wound Transformers and Output Circuit
••
The Power Output Circuitry utilizes 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
••
The MA2275 has five Inputs for high level program
sources and one Phono Input for a Moving Magnet Cartridge.
••
• Tone Control Bypass
••
The Bass and Treble Control Circuit Elements can be removed from the Signal Path.
••
• Low Distortion
••
Distortion levels of all types are less than 0.5%. Music is
amplified with total transparency and accuracy.
••
• Remote Control Operation
••
A Remote Control is included that will allow control of
major front panel controls and switches. There are provisions for connecting External Keypad and/or Sensors,
which allows for enjoyment of your McIntosh System from
other rooms in your home.
••
• Illuminated Power Meters
••
Peak responding Power Output Meters will indicate either
continuously or in a peak hold mode for each channel.
There is also a Meter Illumination Off Mode if desired.
••
• 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.
••
• Fiber Optic Solid State Front Panel Illumination
••
The even Illumination of the Glass Front Panel is accomplished by the combination of custom designed Fiber Optic
Light Diffusers and extra long life Light Emitting Diodes
(LEDs).
••
• Super Mirror Chassis Finish
••
The Stainless Steel Chassis with Super Mirror Finish ensures the pristine beauty of the MA2275 will be retained
for many years.
••
• Electronic Input Switching
••
Digital Logic integrated circuits drive Electromagnetic
Switches on all inputs and operating functions for reliable,
noiseless, distortion free switching.
4
Dimensions
The following dimensions can assist in determining the
best location for your MA2275. There is additional information on page 8 pertaining to installing the MA2275 into
cabinets.
Front View of the MA2275
17-
3/4
45.09cm
16
-3/4
42.55cm
Dimensions
"
8-
7/8
"
22.54cm
"
1/8
10-
25.72cm
"
Rear View of the MA2275
Side View of the MA2275
13-
11/16
34.77cm
17-
45.09cm
"
3/4
"
17"
43.18cm
8-
1/8
"
20.64cm
9-
3/4
"
24.77cm
3/4"
1.91cm
12-
3/4
32.39cm
3-
5/16
"
"
5.87cm
5
Installation of Tubes and Tube Cover
Caution: To prevent electrical shock make sure the AC
POWER CORD IS NOT CONNECTED TO THE
MA2275 . Also do not touch the Vacuum Tube
Connection Pins when inserting or removing them,
as there may be hazardous voltages present at the
Tube Socket Pins even after the MA2275 has been
switched Off for a period of time.
Your MA2275 has gone through an extensive series of performance tests during the manufacturing process. The
MA2275 is supplied with the actual Tubes that were used
to test and confirm the performance of this integrated amplifier. To protect the Vacuum Tubes from possible shipping damage, they are packed in five layers of foam,
placed into the Tube Cover and secured to the MA2275
Chassis.
Note: Gloves or a soft cloth will prevent “fingerprinting” of
the Tubes during their installation.
1. Orient the MA2275 so the right Side Panel is facing
you. Refer to figure 1.
2. Using an appropriate screwdriver, remove the Tube
Cover Fastening Screw.
3. In a similar manner, remove the Tube Cover Fastening Screw from the left side of the integrated amplifier.
4. Remove the tube cover from the MA2275 Chassis.
5. Orient the Tube Cover to the wide opening along one
side of its longer dimension. Refer to figure 2.
6. Remove the first layer of foam to expose the Tubes.
Refer to figure 3.
7. Carefully remove the Tubes from the foam and temporarily place them in a safe location.
8. Remove the remaining foam from the Tube Cover
and retain all five pieces for possible future use.
Fastening
Screw
Location
Tube Cover with
Layers of Foam
and Tubes
Power Output Tubes
V3L - KT88/6550 Tube
Tube Cover
Figure 1
Figure 2
Small Signal Tubes
Figure 3
The MA2275 Chassis has nomenclature screened on it to
specify the location in the circuit and Tube Type for each
channel. Refer to figure 4.
Note: It is extremely important to insert the Tubes in the
correct location.
Power Output Tubes:
1. Orient the Chassis so the Front Panel of the Amplifier
is facing you.
2. Locate a KT88 or 6550 Power Output Tube.
3. On the top left side of the amplifier, locate the Tube
Socket that has the nomenclature V3L KT88/6550
next to it on the chassis.
4. Orient the Tube so the key on the base of the Tube is
aligned with the corresponding key on the Tube
Socket.
5. Carefully insert the Tube into the socket until the base
of the Tube is fully seated in the Tube Socket.
6
V4 - 12AX7A Tube
V1R - 12AT7 Tube
Figure 4
Installation of Tubes, Tube Cover, Location and Ventilation
6. Repeat the above the steps for the remaining 3 Power
Output Tubes.
There are two different types of Small Signal Tubes
(12AX7A and 12AT7) used in each channel. Tube type can
be found on the outside of the Tube. The MA2275 will not
function if they are inserted into the wrong socket.
Small Signal Tubes:
1. Locate a 12AX7A Tube.
2. On the top center area of the amplifier, locate the
Tube Socket that has the nomenclature V4 12AX7A
next to it on the chassis. Refer to figure 4.
3. Orient the Tube so the area where no pins are located
on the base of the Tube is aligned with the corresponding area on the Tube Socket.
4. Carefully insert the Tube into the socket until the base
of the Tube is fully seated in the Tube Socket.
5. Repeat the above steps for the remaining three
12AX7A Tubes. Refer to figure 5.
6. Locate a 12AT7 Tube.
7. On the right side of the amplifier, locate the Tube
Socket that has the nomenclature V1R 12AT7 next to
it on the chassis. Refer to figure 4.
8. Insert the Tube, following the same procedure as in
steps 3 and 4.
9. Repeat steps 6-9 for the remaining 12AT7 Tube. Refer to figure 5.
Caution: To prevent electrical shock make sure the MA2275
Tube Cover is installed before connecting the AC
Power Cord.
Before operating the MA2275, locate the previously removed Tube Cover and perform the following steps:
Installing the Tube Cover:
1. The Tube Cover has a wide opening along one side
of its longer dimension. Orient this wide opening so
it is facing towards you.
2. Carefully place the Tube Cover onto the MA2275.
Refer to figure 6.
3. Using an appropriate screwdriver secure the Tube
Cover to the chassis using the previously installed
screws.
KT88/
6550
12AX7A
KT88/
6550
12AT7
Figure 5
Tube Cover
Tube Cover Fastening Screw Locations
Fastening
Screw
Location
Tube Cover
Figure 6
Warm Air
Location and Ventilation
Adequate ventilation extends the trouble free life of the
MA2275. The suggested minimum space for operating the
MA2275 is 24 inches (60.96cm) in width, 20 inches
(50.8cm) depth, and 22.5 inches (57.15cm) in height. Always allow air to flow through the ventilation holes on the
bottom of the amplifier and a means for the warm air to escape at the top, refer to figure 7. For installation of the
MA2275 into a cabinet, refer to the next page.
Cool Air
Figure 7
7
Installation in a Custom Cabinet
The MA2275 can be placed upright on a table or shelf,
standing on its four feet. It also can be custom installed in a
piece of furniture or cabinet of your choice. The four feet
may be removed from the bottom of the MA2275 when it
is custom installed as outlined below. The four feet
together with the mounting
screws should be retained
for possible future use if the
MA2275 is removed from
the custom installation and
used free standing. Install
the four supplied chassis
spacers into the threaded
MA2275 Front Panel
Custom Cabinet Cutout
openings on the bottom located next to the just removed four feet. The required panel cutout, ventilation cutout and unit dimensions are shown.
Always provide ad-
equate ventilation for your
Cabinet
Front
Panel
MA2275. Cool operation
ensures the longest possible
operating life for any elec-
Opening
for Ventilation
tronic instrument. Do not
install the MA2275 directly
above a heat generating
component such as a high
powered amplifier. If the
MA2275 Side View
in Custom Cabinet
MA2275 is installed in a
cabinet, a quiet running
ventilation fan can be a
definite asset in maintaining the coolest possible operating temperature.
A custom cabinet instal-
Support
Shelf
lation should provide the
following minimum spacing dimensions for cool operation. Allow at least 12
inches (30.48cm) above the
top, 2 inches (5.08cm) below the bottom and 3
MA2275 Bottom View
in Custom Cabinet
inches (7.62cm) on each
side of the amplifier, so that
airflow is not obstructed.
Allow 20 inches (50.8cm)
2
depth behind the front
"
5.08cm
panel. Allow 1 inch (2.54cm) in front of the mounting
panel for knob clearance. Be sure to cut out a ventilation
hole in the mounting shelf according to the dimensions in
the drawing.
17-
1/4
"
43.82cm
8-
1/4
"
20.96cm
Cutout Opening for Custom Mounting
12"
30.48cm
Cutout Opening for Ventilation
1
-7/8
"
4.76cm
13-
34.77cm
Cutout Opening
for Ventilation
11/16
13-
33.34cm
"
1/8
9-
23.34cm
"
3/16
"
Chassis
Spacers
10
-5/16
"
26.19cm
8
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