Power Amplifier
MC205
Owner’s Manual
McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 FAX: 607-724-0549
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Thank You
Table of Contents
Your decision to own this McIntosh MC205 Power Ampli-
fier ranks you at the very top among discriminating music
listeners. You now have “The Best.” The McIntosh dedica-
tion 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.
Safety Instructions............................................................2
Thank You and Please Take a Moment.............................3
Technical Assistance and Customer Service....................3
Table of Contents ..............................................................3
General Information .........................................................3
Connector and Cable Information ....................................4
Introduction.......................................................................4
Performance Features .......................................................4
Dimensions .......................................................................5
Installation ........................................................................6
Connections:
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:
Rear Panel Connections....................................................7
How to Connect for a Five Channel System.....................8
How to Connect for a Seven Channel System................ 10
How to Connect for a Five Channel and
Serial Number: __________________________________
Purchase Date: __________________________________
Dealer Name: ___________________________________
Zone B System................................................................ 12
Front Panel Features:
Front Panel Displaysand Switches.................................. 14
Operation:
How to Operate the MC205............................................ 15
Additional Information:
Specifications.................................................................. 18
Packing Instruction.........................................................19
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:
General Information
1. For additional connection information, refer to the
owner’s manual(s) for any component(s) connected to
the MC205 Power Amplifier.
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, New York 13903
Phone: 607-723-1545
Fax: 607-724-0549
2. The Main AC Power going to the MC205 and any other
McIntosh Component(s) should not be applied until all
the system components are connected together. Failure
to do so could result in malfunctioning of some or all of
the system’s normal operations. When the MC205 and
other McIntosh Components are in their Standby Power
Off Mode, some of the circuitry inside each compo-
nent is active and communication is occurring between
them.
3. In the event the MC205 overheats, due to improper
ventilation and/or high ambient temperature, the protec-
tion circuits will activate. The Front Panel Power Guard
LEDs will continuously indicate ON and the audio will
be muted. When the MC205 has returned to a safe oper-
ating temperature, normal operation will resume.
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 2006 © by McIntosh Laboratory, Inc.
3
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Connector Information, Introduction and Performance Features
Connector and Cable Information
XLR Connectors
Below is the Pin configuration for the XLR Balanced Input
Connectors on the MC205. Refer to the diagram for con-
nection:
speakers, while at the same time delivering identical power
output. A peak output current of 25 amperes per channel
ensures that it will successfully drive high quality Loud-
speakers such as McIntosh, for a truly exciting sound
experience.
PIN 1: Shield/Ground
PIN 2: + Output
PIN 3: - Output
• Balanced and Unbalanced Inputs
Balanced connections guard against induced noise and al-
low long cable runs without compromising sound quality.
PIN 1
PIN 2
PIN 3
Power Control Connector
The MC205’s Power Control Inputs receive On/Off signals
of +5 volts. An additional connection
• Sentry Monitor and Thermal Protection
McIntosh Sentry Monitor power output stage protection
circuits ensure the MC205 will have a long and trouble free
operating life. Built-in thermal protection circuits guard
against overheating.
Power
is for controlling the illumination of
Control
the MC205 Power Output Meters.
Meter
The 1/8 inch stereo mini phone plug
connects to a McIntosh A/V Control
Illumination
Control
Ground
Center Power Control Output.
Note: The Power Control Connecting Cable is available from
• Illuminated Power Meters
the McIntosh Parts Department:
The Illuminated Power Output Watt Meters on the MC205
are peak responding, and indicate the power output of the
amplifier.
Data and Power Control Cable Part No. 170-202
Six foot, shielded 2 conductor, with 1/8 inch stereo mini
phone plugs on each end.
• Power Control
The McIntosh Power Control Circuit allows for remote
turn-on of the MC205 Power Amplifier from a McIntosh
A/V Control Center or Preamplifier for a single or dual
Zone System.
Introduction
Now you can take advantage of traditional McIntosh stan-
dards of excellence in the MC205 Power Amplifier. The
five channel Power Amplifier produces a power output of
200 watts per channel and will drive quality Loudspeakers
to a high level of performance. The MC205 reproduction is
sonically transparent and absolutely accurate. The McIn-
tosh Sound is “The Sound of the Music Itself.”
• Special Power Supply
A regulated Power Supply and a very large Toroidal
Wound Power Transformer, ensures stable noise free op-
eration even though the power line varies.
• Fiber Optic Solid State Front Panel Illumination
The even Illumination of the Front Panel is accomplished
by the combination of custom designed Fiber Optic Light
Diffusers and extra long life Light Emitting Diodes
(LEDs). The glass Front Panel ensures the pristine beauty
of the MC205 will be retained for many years.
Performance Features
• Power Output
The MC205 consists of five Power Amplifier Channels,
each capable of 200 watts into 4 ohm or 8 ohm Loudspeak-
ers with less than 0.005% distortion.
• Power Guard
The patented McIntosh Power Guard Circuit prevents
the amplifier from being over driven into clipping, with
its harsh distorted sound that can damage your valuable
Loudspeakers.
• Dynamic Power ManagerTM
The MC205’s Dynamic Power Manager (DPM) circuitry
allows for the connection of either 4 ohm or 8 ohm Loud-
4
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Dimensions
Dimensions
The following dimensions can assist in determining the
best location for your MC205. There is additional informa-
tion on the next page pertaining to installing the MC205
into cabinets.
17-1/2"
44.45cm
Front View of the MC205
8-7/8"
22.54cm
9-7/16"
23.97cm
16-13/16"
42.70cm
Rear View of the MC205
11-3/4"
29.85cm
18-3/4"
47.63cm
16-7/16"
41.75cm
8-1/4"
20.96cm
Side View of the MC205
3/16"
0.48cm
7/8"
2.22cm
2"
5.08cm
12"
30.48cm
5
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Installation
Installation
The MC205 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 MC205 when it is
custom installed as outlined below. The four feet together
with the mounting screws should be retained for pos-
sible future use if the MC205 is removed from the custom
installation and used free standing. The required panel
cutout, ventilation cutout and unit dimensions are shown.
Always provide ade-
fier, so that airflow is not obstructed. Allow 19-1/2 inches
(49.53cm) depth behind the front panel. Allow 7/8 inch
(2.22cm) in front of the mounting panel1 for clearance. Be
sure to cut out a ventilation hole in the mounting shelf ac-
cording to the dimensions in the drawing.
1 When the MC205 is installed together with other McIntosh
Components, check clearances on all components before
proceeding.
quate ventilation for
your MC205. Cool
17-1/16"
43.34cm
operation ensures
the longest pos-
sible operating life
for any electronic
instrument. Do not
install the MC205
directly above a heat
MC205 Front Panel
Custom Cabinet Cutout
8-5/16"
21.11cm
generating compo-
nent such as a high
powered amplifier.
If all the compo-
nents are installed
in a single cabinet,
6"
15.24cm
Cutout Opening
Cabinet
Front
Panel
a quiet running
for
Custom Mounting
ventilation fan can
be a definite asset
in maintaining all
the system compo-
nents at the coolest
possible operating
temperature.
A custom cabinet
installation should
provide the follow-
ing minimum spac-
ing dimensions for
cool operation.
Opening
for Ventilation
MC205 Side View
in Custom Cabinet
Cutout Opening for Ventilation
Chassis
Spacers
Support
Shelf
3-3/4"
8.57cm
Allow at least 6
inches (15.24cm)
above the top, 2
inches (5.08cm)
below the bottom
and 1 inch (2.54cm)
on each side of
12-1/4"
31.12cm
11"
27.9cm
Cutout
Opening
for
MC205 Bottom View
in Custom Cabinet
12-3/8"
31.43cm
Center the
opening horizontally
with the
15-3/4"
Ventilation
40.00cm
MC205 Chassis
the Power Ampli-
9-7/8"
25.08cm
11-1/2"
29.21cm
6
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Rear Panel Connections
Connect the MC205
power cord to a live AC for a 4 ohm or 8 ohm
outlet. Refer to the rear Loudspeaker for Chan-
panel to determine the
correct voltage
OUTPUT Connections
Selects the impedance
(4 or 8 ohms) of the
Loudspeakers connect-
ed to the MC205
OUTPUT Connections Balanced INPUT
for a 4 ohm or 8 ohm
Channel 1 (Left
Loudspeaker for Chan- Front)
nel 1 (Left Front)
nel 5 (Right Front)
OUTPUT Connections
OUTPUT Connec-
tions for a 4 ohm or
8 ohm Loudspeaker
for Channel 2 (Left
Surround) or ZONE
B Left Channel
POWER CONTROL ZA receives
OUTPUT Connections
for a 4 ohm or 8 ohm
Loudspeaker for Chan-
nel 3 (Center Front)
for a 4 ohm or 8 ohm
Loudspeaker for Chan-
nel 4 (Right Surround)
or ZONE B Right
Channel
turn On/Off signals from a McIn-
tosh component for Zone A (Chan-
nels 1- 5). ZB receives turn On/Off
signals from a McIntosh component
for Zone B (Channels 2 and 4).
Balanced INPUT Channel 4
(Right Surround) or ZONE
B Right Channel
Balanced INPUT Channel 2 Balanced INPUTS Channel
(Left Surround) or ZONE B 5 (Right Front) and Channel
Left Channel
3 (Center Front)
Main Fuse, refer
Unbalanced INPUTs Channel
2 (Left Surround) and Channel
4 (Right Surround) or ZONE B
Left and Right Channels
Unbalanced INPUT Channel 5
(Right Front)
Unbalanced INPUTs Channel
1 (Left Front) and Channel 3
(Center Front)
to the rear panel
for the correct fuse
size and rating
7
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How to Connect for a Five Channel System
Caution: The supplied AC Power Cord should not be con-
nected to the Rear Panel of the MC205 Power Am-
plifier until after the Loudspeaker Connections
have been made. Failure to observe this could
result in Electric Shock.
1. Connect Audio Cables from the Zone A Unbalanced
Outputs of a McIntosh A/V Control Center to the
MC205 INPUTS (Channels 1-5), making sure to match
up the channel identifications between both units.
Note: In place of the Unbalanced Audio Cables, Balanced
Cables may be used.
Spade lug or prepared wire connection:
Insert the spade lug connector or prepared section of the
cable end into the terminal side access hole, and tighten
the terminal cap until the cable is firmly clamped into the
terminal so the wires cannot slip out. Refer to figures 4, 5
& 6.
2. Connect a power control cable from the McIntosh
A/V Control Center Zone A Power Control Out to the
MC205 POWER CONTROL ZA.
When connecting Loudspeakers to the MC205 it is very
important to use cables of adequate size, so there is little to
no power loss in the cables. The size is specified in Gauge
Numbers or AWG (American Wire Gauge). The smaller
the Gauge number, the larger the 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. Prepare the Loudspeaker Hookup Cables that attach
to the MC205 Power Amplifier by choosing one of the
methods below:
Banana plug connection:
Tighten the top portion of the terminal post and insert the
banana plug into the opening at the top of the terminal.
Refer to figure 7.
Note: The use of Banana Plugs is for use
in the United States and Canada
only.
4. Connect the Loudspeaker Hookup
Cables from the MC205 OUTPUT
Terminals to the Loudspeakers,
being careful to observe the correct
polarities and channel designation.
WARNING: Loudspeaker terminals are hazardous live
and present a risk of electric shock. For ad-
ditional instruction on making Loudspeaker
Connections contact your McIntosh Dealer
or McIntosh Technical Support.
Bare wire cable ends:
Carefully remove sufficient insulation from the cable ends,
refer to figures 1, 2 & 3. If the cable is stranded, carefully
twist the strands
together as tightly
as possible.
5. Place the IMPEDANCE Switch to the position (4 ohm
or 8 ohm) that matches the impedance of the connected
Loudspeakers. In the event that some of the Loud-
speakers in the system are of different impedance, use
the impedance of the Left and Right Front Loudspeak-
ers to set the IMPEDANCE Switch position.
6. Connect the MC205 Power Cord to an active AC outlet.
Note: If desired,
the twisted
ends can be
tinned with
Figure 2
Figure 3
Figure 1
solder to keep the strands together, or attach spade lug
and/or banana connector.
McIntosh A/V Control Center
8
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How to Connect for a Five Channel System
Center Front
Loudspeaker
Right Front
Loudspeaker
Left Front
Loudspeaker
-
+
+
-
-
+
To AC Outlet
Left Surround
Loudspeaker
Right Surround
Loudspeaker
+
-
-
+
9
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How to Connect for a Seven Channel System
Caution: The supplied AC Power Cord should not be con-
nected to the Rear Panel of the MC205 Power Am-
plifier until after the Loudspeaker Connections
have been made. Failure to observe this could
result in Electric Shock.
1. Connect Audio Cables from the Zone A Unbalanced
Outputs of a McIntosh A/V Control Center to the
MC205 INPUTS (Channels 1-5), making sure to match
up the channel identifications between both units.
Notes: In place of the Unbalanced Audio Cables, Balanced
Cables may be used. The Left and Right Front Chan-
nels are amplified by a McIntosh Two Channel Power
Amplifier.
Spade lug or prepared wire connection:
Insert the spade lug connector or prepared section of the
cable end into the terminal side access hole, and tighten
the terminal cap until the cable is firmly clamped into the
terminal so the wires cannot slip out. Refer to figures 4, 5
& 6.
Banana plug connection:
Tighten the top portion of the terminal post and insert the
banana plug into the opening at the top of the terminal.
Refer to figure 7.
2. Connect a power control cable from the McIntosh
A/V Control Center Zone A Power Control Out to the
McIntosh Two Channel Power Amplifier Power Control
Input Jack. Connect a second power control cable from
the McIntosh two Channel Power Amplifier Power
Control Output jack to the MC205 POWER CONTROL
ZA Jack.
When connecting Loudspeakers to the MC205 it is very
important to use cables of adequate size, so there is little to
no power loss in the cables. The size is specified in Gauge
Numbers or AWG (American Wire Gauge). The smaller
the Gauge number, the larger the 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. Prepare the Loudspeaker Hookup Cables that attach
to the MC205 Power Amplifier by choosing one of the
methods below:
Bare wire cable ends:
Carefully remove
sufficient insula-
tion from the cable
Note: The use of Banana Plugs is for use
in the United States and Canada
only.
4. Connect the Loudspeaker Hookup
Cables from the MC205 OUTPUT
Terminals to the Loudspeakers, being
careful to observe the correct polari-
ties and channel designation.
WARNING: Loudspeaker terminals are hazardous live
and present a risk of electric shock. For ad-
ditional instruction on making Loudspeaker
Connections contact your McIntosh Dealer
or McIntosh Technical Support.
5. Place the IMPEDANCE Switch to the position (4 ohm
or 8 ohm) that matches the impedance of the connected
Loudspeakers. In the event that some of the Loud-
speakers in the system are of different impedance, use
the impedance of the Left and Right Front Loudspeak-
ers to set the IMPEDANCE Switch position.
6. Connect the MC205 Power Cord to an active AC outlet.
ends, refer to fig-
ures 1, 2 & 3. If the
cable is stranded,
Figure 2
Figure 3
Figure 1
McIntosh A/V Control Center
carefully twist the strands
together as tightly as pos-
sible.
Note: If desired, the
twisted ends can be
tinned with solder
to keep the strands
together, or attach
spade lug and/or
banana connector.
10
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How to Connect for a Seven Channel System
McIntosh Two Channel Power Amplifier
Right Front
Left Front
Loudspeaker
Loudspeaker
-
Center Front
Loudspeaker
+
To AC Outlet
Right Surround
Loudspeaker
Left Surround
Loudspeaker
-
-
+
+
Back Right
Surround
Back Left
Surround
Loudspeaker
Loudspeaker
+
-
-
+
11
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How to Connect for a Five Channel and Zone B
System
Caution: The supplied AC Power Cord should not be con-
nected to the Rear Panel of the MC205 Power Am-
plifier until after the Loudspeaker Connections
have been made. Failure to observe this could
result in Electric Shock.
1. Connect Audio Cables from the Zone A Unbalanced
Outputs of a McIntosh A/V Control Center to the
MC205 INPUTS (Channels 1, 3 and 5), making sure
to match up the channel identifications between both
units. Connect Audio Cables from the Zone B Unbal-
anced Outputs of a McIntosh A/V Control Center to
the MC205 INPUTS (Channels 2 and 4), making sure
to match up the channel identifications between both
units.
Spade lug or prepared wire connection:
Insert the spade lug
connector or prepared
section of the cable end
into the terminal side
access hole, and tighten
Figure 2
Figure 3
Figure 1
the terminal cap until the
cable is firmly clamped into the terminal so the wires can-
not slip out. Refer to figures 4, 5 & 6.
Note: In place of the Unbalanced Audio Cables, Balanced
Cables may be used for the Zone A Connections.
2. Connect a power control cable from the McIntosh
A/V Control Center Zone A Power Control Out to the
McIntosh Two Channel Power Amplifier Power Control
Input Jack. Connect a second power control cable from
the McIntosh two Channel Power Amplifier Power
Control Output jack to the MC205 POWER CONTROL
ZA Jack. Connect power control cables from the McIn-
tosh A/V Control Center Zone B Power Control Output
jacks to the MC205 POWER CONTROL ZB jack.
When connecting Loudspeakers to the MC205 it is very
important to use cables of adequate size, so there is little to
no power loss in the cables. The size is specified in Gauge
Numbers or AWG (American Wire Gauge). The smaller
the Gauge number, the larger the wire size:
If your loudspeaker cables are 50 feet (38.1m) or less,
use at least 14 Gauge.
Banana plug connection:
Tighten the top portion of the terminal post and insert the
banana plug into the opening at the top of
the terminal. Refer to figure 7.
Note: The use of Banana Plugs is for use in
the United States and Canada only.
4. Connect the Loudspeaker Hookup
Cables from the MC205 OUTPUT Ter-
minals to the Loudspeakers, being careful to observe
the correct polarities and channel designation.
WARNING: Loudspeaker terminals are hazardous live
and present a risk of electric shock. For ad-
ditional instruction on making Loudspeaker
Connections contact your McIntosh Dealer
or McIntosh Technical Support.
5. Place the IMPEDANCE Switch to the position (4 ohm
or 8 ohm) that matches the impedance of the connected
Loudspeakers. In the event that some of the Loud-
speakers in the system are of different impedance, use
the impedance of the Left and Right Front Loudspeak-
ers to set the IMPEDANCE Switch position.
6. Connect the MC205 Power Cord to an active AC outlet.
If your loudspeaker cables are 100 feet (76.2m) or less,
use at least 12 Gauge.
3. Prepare the Loudspeaker Hookup Cables that attach
to the MC205 Power Amplifier by choosing one of the
methods below:
Bare wire cable ends:
Carefully remove suffi-
McIntosh A/V Control Center
cient insulation from the
cable ends, refer to figures
1, 2 & 3. If the cable is
stranded, carefully twist
the strands together as
tightly as possible.
Note: If desired, the twisted
ends can be tinned
with solder to keep the
strands together, or
attach spade lug and/
or banana connector.
12
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How to Connect for a Five Channel and Zone B System
McIntosh Two Channel Power Amplifier
Right Front
Left Front
Loudspeaker
Loudspeaker
-
Center Front
Loudspeaker
+
To AC Outlet
Right Surround
Loudspeaker
Left Surround
Loudspeaker
-
-
+
+
Zone B Left
Loudspeaker
Zone B Right
Loudspeaker
+
-
-
+
13
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Front Panel Displays and Switches
LED indicates when Am-
plifier Channels 1, 3 or 5
POWER GUARD circuit
activates
Meter indicates the Power
Output of the amplifier for
Channels 1, 3 and 5
LED indicates when
Amplifier Channels 2
or 4 POWER GUARD
circuit activates
POWER Switch Turns
AC Power On or Off/
Remote (On/Off)
METER LIGHTS
Switch selects the
Meter Illumination
On or Off
Standby Power On
Indicator
14
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How to Operate the MC205
How to Operate the MC205
Power
Power Output Meters
With the POWER Switch set to the OFF/REMOTE Posi-
tion, the MC205 will turn On or Off when
an A/V Control Center turns On or Off. For
manual operation, place the POWER Switch
to the ON Position as desired. Refer to figure
8.
The MC205 Power Output Meters are calibrated to allow
for the direct reading of either the Power Output in Watts
or Decibels for Loudspeakers connected to Channels 1, 3
and 5. The meters respond to all the musical information
being produced by the amplifier. They indicate to an accu-
racy of at least 95% of the power output with only a single
cycle of a 2000Hz tone burst. Refer to figure 12.
Note: There must be a power control connec-
tion between the MC205 and the McIn-
tosh A/V Control Center in order for the
Figure 8
remote power turn-on to function.
Meter Illumination
Place the METER LIGHTS Switch to the ON position for
Illuminated Meters or place the switch
to the Off position for no Illumination.
When Power Control Input ZA (Zone
A only) of the MC205 is connected to a
McIntosh A/V Control Center or Pream-
plifier with Remote Meter Illumination
Control, the Meter Illumination will auto-
Figure 12
matically be remotely controlled (On/Off)
with the METER LIGHTS Switch to set
to the ON position. Refer to figure 9.
Figure 9
Impedance Switch
The MC205’s Dynamic Power Manager circuitry allows
for the connection of either 4 ohm or 8 ohm Loudspeakers
to its output terminals, while at the same
time delivering the same power output.
Refer to figure 10. Place the IMPEDANCE
Switch, located on the rear panel, to the
position (4 ohm or 8 ohm) that matches the
Figure 10
impedance of the connected Loudspeak-
ers. In the event that some of the Loud-
speakers in the system are of different
impedance, use the impedance of the Left
and Right Front Loudspeakers to set the
IMPEDANCE Switch position. Refer to
figure 11.
Figure 11
15
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Technical Description
A continuous average power output rating of 200 watts and The MC205 can easily drive 4 ohm speakers, with their
an output current of greater than 25 amperes per channel,
makes this one of the most advanced and powerful ampli-
fiers McIntosh has ever manufactured. Refer to figures 13
and 14. The distortion limits for the MC205 are no more
than 0.005% at rated power output for all frequencies from
20Hz to 20,000Hz. Typical performance at mid frequen-
cies is less than 0.002%. The true distortion readings on
high current demand. Additionally, the MC205 can be used
with 8 ohm speakers, and deliver equal power. McIntosh’s
new DPMTM design enables it to run on higher voltage rails
when connected to less current-hungry 8 ohm speakers and
still deliver 200 watts. The power penalty usually paid with
8 ohm speakers on high current amplifiers does not exist
with this new design.
the MC205
are so low,
it takes
The high efficiency circuit design of the MC205 con-
tributes to low operating temperatures. More than 2100
square inches of heat sink area occupies almost half of the
MC205’s chassis space and keeps the amplifier operating
safely with convection cooling. No fans are needed.
special
measuring
techniques
to make
Protection Circuits
accurate
The MC205 incorporates its version of the McIntosh Sen-
try Monitor output transistor protection circuit. There is
absolutely no compromise in sonic performance with this
circuit, and it ensures safe operation of the amplifier under
even the most extreme operating conditions. The different
types of protection circuits incorporated in the MC205 in-
sure a long and safe operat-
readings.
The MC205
can deliver
the best
possible
perfor-
mance from
any type of
high qual-
ity Loud-
speaker
Input Test Signal
ing life.
The MC205 also includes the
unique patented McIntosh
Power Guard circuit. Power
Guard eliminates the pos-
sibility of ever overdriving
the amplifier into clipping.
Refer to figures 15, 16 and
17. An overdriven amplifier
can produce both audible and
System.
Figure 13
Design Philosophy
The MC205 McIntosh Power Amplifier to uses the recently inaudible distortion levels
Figure 15
developed Dynamic Power ManagerTM (DPM) Circuitry.
exceeding 40%. The audible
Block Diagram
of the
Power Amplifier
(one channel shown)
Figure 14
16
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Technical Description
Power Supply Circuits
To compliment the design of the MC205, there is a high
distortion is unpleasant to hear, but the inaudible ultrasonic
distortion is also undesirable, since it can damage valuable
current power supply for the five power amplifier channels.
Loudspeaker System tweet-
Without Power Guard
Refer to figure 18. The very large Power Transfomer, has
toroidal windings on a toroidal core and can supply over 35
amps of continuous current. Refer to figure 19 (golf ball is
for size comparsion). It is enclosed in the legendary McIn-
tosh Potted
Enclosures
and weighs
over
12.06kg.
The super
size main
filter
ers. You will never experi-
ence the harsh and damaging
distortion due to clipping.
The Power Guard circuit is a
waveform comparator, moni-
toring both the input and out-
put waveforms. Under normal
operating conditions, there
are no differences between
the shape of these waveforms.
If an amplifier channel is
overdriven, there will be a
difference between the two
signal waveforms. When the
difference exceeds 0.3% (equivalent to 0.3% harmonic dis-
tortion), the Power Guard activates the PG light and a dy-
namic electronic attenuator at the amplifier input reduces
Figure 16
capacitors
can store
over 310
Joules of
Figure 19
energy for
the five
the input volume just enough
to prevent any further
With Power Guard
amplifier channels, necessary for the wide dynamic range
that “Digital Audio” demands. Refer to figure 23. The
power amplifier draws high current from the AC power
line. Therefore, it is important that they plug directly into
the wall outlet.
Also, most owners desire one power switch for the whole
audio system. The MC205 is equipped with a circuit that
provides remote Power Control from a McIntosh A/V Con-
trol Center. When the A/V Control Center is switched On,
a (+5V) signal operates the power relay in the MC205. The
MC205 also has a remote Power Control input for Zone B
operation (two of the five channels).
increase in distortion. The
Power Guard circuit acts so
fast that there are absolutely
no audible side effects and
the sonic purity of the music
reproduction is perfectly pre-
served. The MC205 Power
Amplifier with Power Guard
is not limited to just the
rated power output, but will
actually produce distortion
Figure 17
free output well above its rated power due to the McIntosh
philosophy of conservative design.
Block Diagram
of the
Power Supply
Figure 18
17
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Specifications
Specifications
Power Output
Power Requirements
Minimum sine wave continuous average power output per
channel, all channels operating is:
200 watts into a 4 ohm or 8 ohm load
100 Volts, 50/60Hz at 12 Amps
110 Volts, 50/60Hz at 11 Amps
120 Volts, 50/60Hz at 10 Amps
220 Volts, 50/60Hz at 6 Amps
230 Volts, 50/60Hz at 6 Amps
240 Volts, 50/60Hz at 6 Amps
Output Load Impedance
8 and 4 ohms
Note: Refer to the rear panel of the MC205 for the correct
voltage.
Rated Power Band
20Hz to 20,000Hz
Overall Dimensions
Total Harmonic Distortion
Width is 17-1/2 inches (44.45cm)
Height is 9-7/16 inches (23.97cm) including feet
Depth is 21 inches (53.3cm) including the Front Panel and
Cables
0.005% maximum harmonic distortion at any power level
from 250 milliwatts to rated power, 20Hz to 20,000Hz
Dynamic Headroom
1.7dB
Weight
81 pounds (44.2 kg) net, 114 pounds (51.8 kg) in shipping
carton
Frequency Response
+0, -0.25dB from 20Hz to 20,000Hz
+0, -3dB from 10Hz to 100,000Hz
Shipping Carton Dimensions
Width is 29-1/2 inches (74.93cm)
Depth is 30-1/2 inches (77.47cm)
Height is 17-1/2 inches (44.45cm)
Input Sensitivity (for rated output)
2.0 Volt Balanced with a 4 ohm Loudspeaker
1.0 Volt Unbalanced with a 4 ohm Loudspeaker
2.8 Volt Balanced with a 8 ohm Loudspeaker
1.4 Volt Unbalanced with a 8 ohm Loudspeaker
Signal To Noise Ratio (A-Weighted)
112dB below rated output
Intermodulation Distortion
0.005% maximum, if the instantaneous peak power output
is rated power or less per channel with all channels op-
erating for any combination of frequencies from 20Hz to
20,000Hz.
Wide Band Damping Factor
Greater than 70 at 4 ohms
Greater than 140 at 8 ohms
Input Impedance
20,000 ohms Balanced
10,000 ohms Unbalanced
Power Guard
Less than 2% THD with up to 14dB overdrive at 1,000Hz
18
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Packing Instructions
Packing Instructions
In the event it is necessary to repack the equipment for
shipment, the equipment must be packed exactly as shown
below. It is very important that the four plastic feet are
attached to the bottom of the equipment. Four 1/4 - 20 x
2-1/2 inch screws and washers must be used to fasten the
unit securely to the bottom pad and shipping skid. This
will ensure the proper equipment location on the bottom
pad. Failure to do this will result in shipping damage.
Use the original shipping carton and interior parts only
if they are all in good serviceable condition. If a shipping
carton or any of the interior part(s) are needed, please call
or write Customer Service Department of McIntosh Labo-
ratory. Please see the Part List for the correct part numbers.
Quantity Part Number Description
1
1
2
2
2
034052
034051
034054
034186
034187
Shipping carton top
Shipping carton bottom
Foam Pad (top and bottom)
Foam Pad (front and rear)
Foam Pad (sides)
1
1
1
1
4
4
034136
034137
034188
034264
101212
104058
Inner carton top
Inner carton bottom
Foam Pad (inner carton)
Shipping skid
1/4 - 20x2-1/4 cap screw
Flat washer
19
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McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, NY 13903
The continuous improvement of its products is the
policy of McIntosh Laboratory Incorporated who
reserve the right to improve design without notice.
Printed in the U.S.A.
McIntosh Part No. 04101300
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