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
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.
18. Do not expose batteries to excessive heat such as
sunshine, fire or the like.
2
Thank You
Table of Contents
Your decision to own this McIntosh MC205 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: ___________________________________
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: 607-724-0549
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
Safety Instructions ............................................................
Thank You and Please Take a Moment .............................
Technical Assistance and Customer Service ....................3
Table of Contents .............................................................. 3
General Information .........................................................3
Connector and Cable Information ....................................4
Introduction .......................................................................
Performance Features .......................................................4
Dimensions .......................................................................5
Installation ........................................................................ 6
Connections:
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
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
General Information
1. For additional connection information, refer to the
owner’s manual(s) for any component(s) connected to
the MC205 Power Amplifier.
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 component 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 protection 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 operating temperature, normal operation will resume.
2
3
4
Copyright 2006 © by McIntosh Laboratory, Inc.
3
Connector Information, Introduction and Performance Features
PIN 1
PIN 2
PIN 3
Power
Control
Meter
Illumination
Control
Ground
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 connection:
PIN 1: Shield/Ground
PIN 2: + Output
PIN 3: - Output
Power Control Connector
The MC205’s Power Control Inputs receive On/Off signals
of +5 volts. An additional connection
is for controlling the illumination of
the MC205 Power Output Meters.
The 1/8 inch stereo mini phone plug
connects to a McIntosh A/V Control
Center Power Control Output.
Note: The Power Control Connecting Cable is available from
the McIntosh Parts Department:
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.
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 Loudspeakers such as McIntosh, for a truly exciting sound
experience.
• Balanced and Unbalanced Inputs
Balanced connections guard against induced noise and al
-
low long cable runs without compromising sound quality.
• 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.
• Illuminated Power Meters
The Illuminated Power Output Watt Meters on the MC205
are peak responding, and indicate the power output of the
amplifier.
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 McIntosh Sound is “The Sound of the Music Itself.”
-
Performance Features
• Power Output
The MC205 consists of five Power Amplifier Channels,
each capable of 200 watts into 4 ohm or 8 ohm Loudspeakers 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.
• 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.
• 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.
• Dynamic Power Manager
TM
The MC205’s Dynamic Power Manager (DPM) circuitry
allows for the connection of either 4 ohm or 8 ohm Loud-
4
Dimensions
17-1/2"
44.45cm
8-7/8"
22.54cm
Front View of the MC205
Rear View of the MC205
Side View of the MC205
18-3/4"
47.63cm
3/16"
0.48cm
7/8"
2.22cm
8-1/4"
20.96cm
12"
30.48cm
16-7/16"
41.75cm
2"
5.08cm
9-7/16"
23.97cm
11-3/4"
29.85cm
16-13/16"
42.70cm
The following dimensions can assist in determining the
best location for your MC205. There is additional information on the next page pertaining to installing the MC205
into cabinets.
Dimensions
5
Installation
8-5/16"
21.11cm
17-1/16"
43.34cm
MC205 Front Panel
Custom Cabinet Cutout
Cutout
Opening
for
Ventilation
Cutout Opening for Ventilation
Support
Shelf
Cabinet
Front
Panel
Chassis
Spacers
MC205 Side View
in Custom Cabinet
MC205 Bottom View
in Custom Cabinet
12-1/4"
31.12cm
12-3/8"
31.43cm
11-1/2"
29.21cm
3-3/4"
8.57cm
Cutout Opening
for
Custom Mounting
6"
15.24cm
Opening
for Ventilation
Center the
opening horizontally
with the
MC205 Chassis
15-3/4"
40.00cm
9-7/8"
25.08cm
11"
27.9cm
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 possible 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 adequate ventilation for
your MC205. Cool
operation ensures
the longest possible operating life
for any electronic
instrument. Do not
install the MC205
directly above a heat
generating component such as a high
powered amplifier.
If all the components are installed
in a single cabinet,
a quiet running
ventilation fan can
be a definite asset
in maintaining all
the system components at the coolest
possible operating
temperature.
A custom cabinet
installation should
provide the following minimum spacing dimensions for
cool operation.
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
the Power Ampli-
6
Installation
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 according to the dimensions in the drawing.
1
When the MC205 is installed together with other McIntosh
Components, check clearances on all components before
proceeding.
Rear Panel Connections
Connect the MC205
power cord to a live AC
outlet. Refer to the rear
panel to determine the
correct voltage
OUTPUT Connections
for a 4 ohm or 8 ohm
Loudspeaker for Chan
nel 4 (Right Surround)
or ZONE B Right
Channel
OUTPUT Connections
for a 4 ohm or 8 ohm
Loudspeaker for Chan
nel 5 (Right Front)
OUTPUT Connec
tions for a 4 ohm or
8 ohm Loudspeaker
for Channel 2 (Left
Surround) or ZONE
B Left Channel
Selects the impedance
(4 or 8 ohms) of the
Loudspeakers connect-
ed to the MC205
-
POWER CONTROL ZA receives
turn On/Off signals from a McIn
tosh component for Zone A (Channels 1- 5). ZB receives turn On/Off
signals from a McIntosh component
for Zone B (Channels 2 and 4).
OUTPUT Connections
for a 4 ohm or 8 ohm
Loudspeaker for Chan
nel 1 (Left Front)
OUTPUT Connections
for a 4 ohm or 8 ohm
Loudspeaker for Chan
nel 3 (Center Front)
Balanced INPUT
Channel 1 (Left
Front)
-
-
Balanced INPUT Channel 4
(Right Surround) or ZONE
B Right Channel
Main Fuse, refer
to the rear panel
for the correct fuse
size and rating
Unbalanced INPUTs Channel
2 (Left Surround) and Channel
4 (Right Surround) or ZONE B
Left and Right Channels
Balanced INPUT Channel 2
(Left Surround) or ZONE B
Left Channel
Unbalanced INPUT Channel 5
(Right Front)
Balanced INPUTS Channel
5 (Right Front) and Channel
3 (Center Front)
Unbalanced INPUTs Channel
1 (Left Front) and Channel 3
(Center Front)
7
How to Connect for a Five Channel System
Figure 1
Figure 2
Figure 3
Caution: The supplied AC Power Cord should not be con-
nected to the Rear Panel of the MC205 Power Amplifier 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.
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:
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.
Note: If desired,
the twisted
ends can be
tinned with
solder to keep the strands together, or attach spade lug
and/or banana connector.
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.
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 additional 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 Loudspeakers in the system are of different impedance, use
the impedance of the Left and Right Front Loudspeakers to set the IMPEDANCE Switch position.
6. Connect the MC205 Power Cord to an active AC outlet.
McIntosh A/V Control Center
8
How to Connect for a Five Channel System
Left Front
Loudspeaker
-
+
Center Front
Loudspeaker
Right Front
Loudspeaker
-
+
+
-
To AC Outlet
Left Surround
Loudspeaker
-
+
Right Surround
Loudspeaker
+
-
9
How to Connect for a Seven Channel System
Figure 1
Figure 2
Figure 3
Caution: The supplied AC Power Cord should not be con-
nected to the Rear Panel of the MC205 Power Amplifier 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 Channels are amplified by a McIntosh Two Channel Power
Amplifier.
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 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.
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.
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 additional 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 Loudspeakers in the system are of different impedance, use
the impedance of the Left and Right Front Loudspeakers to set the IMPEDANCE Switch position.
6. Connect the MC205 Power Cord to an active AC outlet.
McIntosh A/V Control Center
10
How to Connect for a Seven Channel System
McIntosh Two Channel Power Amplifier
Right Front
Loudspeaker
Center Front
Loudspeaker
Left Front
Loudspeaker
-
+
To AC Outlet
-
+
Right Surround
Loudspeaker
Back Right
Surround
Loudspeaker
-
+
Left Surround
Loudspeaker
-
+
Back Left
Surround
Loudspeaker
+
-
11
How to Connect for a Five Channel and Zone B
Figure 1
Figure 2
Figure 3
System
Caution: The supplied AC Power Cord should not be con-
nected to the Rear Panel of the MC205 Power Amplifier 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 Unbalanced 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.
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 McIntosh 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.
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-
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.
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.
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 additional 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 Loudspeakers in the system are of different impedance, use
the impedance of the Left and Right Front Loudspeakers to set the IMPEDANCE Switch position.
6. Connect the MC205 Power Cord to an active AC outlet.
McIntosh A/V Control Center
12
How to Connect for a Five Channel and Zone B System
McIntosh Two Channel Power Amplifier
Right Front
Loudspeaker
Center Front
Loudspeaker
Left Front
Loudspeaker
-
+
To AC Outlet
-
+
Right Surround
Loudspeaker
Zone B Left
Loudspeaker
-
+
Left Surround
Loudspeaker
-
+
Zone B Right
Loudspeaker
+
-
13
LED indicates when Amplifier Channels 1, 3 or 5
POWER GUARD circuit
activates
Front Panel Displays and Switches
Meter indicates the Power
Output of the amplifier for
Channels 1, 3 and 5
METER LIGHTS
Switch selects the
Meter Illumination
On or Off
14
LED indicates when
Amplifier Channels 2
or 4 POWER GUARD
circuit activates
POWER Switch Turns
AC Power On or Off/
Remote (On/Off)
Standby Power On
Indicator
How to Operate the MC205
Power
With the POWER Switch set to the OFF/REMOTE Position, 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.
Note: There must be a power control connec-
tion between the MC205 and the McIntosh A/V Control Center in order for the
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 Preamplifier with Remote Meter Illumination
Control, the Meter Illumination will automatically be remotely controlled (On/Off)
with the METER LIGHTS Switch to set
to the ON position. Refer to figure 9.
Figure 8
Figure 9
How to Operate the MC205
Power Output Meters
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 accuracy of at least 95% of the power output with only a single
cycle of a 2000Hz tone burst. Refer to figure 12.
Figure 12
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
impedance of the connected Loudspeak
-
Figure 10
ers. In the event that some of the Loudspeakers in the system are of different
impedance, use the impedance of the Left
and Right Front Loudspeakers to set the
Figure 11
IMPEDANCE Switch position. Refer to
figure 11.
15
Technical Description
A continuous average power output rating of 200 watts and
an output current of greater than 25 amperes per channel,
makes this one of the most advanced and powerful amplifiers 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 frequencies is less than 0.002%. The true distortion readings on
the MC205
are so low,
it takes
special
measuring
techniques
to make
accurate
readings.
The MC205
can deliver
the best
possible
performance from
any type of
high quality Loudspeaker
System.
Figure 13
Design Philosophy
The MC205 McIntosh Power Amplifier to uses the recently
developed Dynamic Power Manager
TM
(DPM) Circuitry.
The MC205 can easily drive 4 ohm speakers, with their
high current demand. Additionally, the MC205 can be used
with 8 ohm speakers, and deliver equal power. McIntosh’s
new DPM
TM
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 high efficiency circuit design of the MC205 contributes 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.
Protection Circuits
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 insure a long and safe operating life.
Input Test Signal
The MC205 also includes the
unique patented McIntosh
Power Guard circuit. Power
Guard eliminates the possibility of ever overdriving
the amplifier into clipping.
Refer to figures 15, 16 and
17. An overdriven amplifier
can produce both audible and
inaudible distortion levels
exceeding 40%. The audible
Figure 15
16
Block Diagram
of the
Power Amplifier
(one channel shown)
Figure 14
Technical Description
distortion is unpleasant to hear, but the inaudible ultrasonic
distortion is also undesirable, since it can damage valuable
Loudspeaker System tweet
-
Without Power Guard
ers. You will never experience the harsh and damaging
distortion due to clipping.
The Power Guard circuit is a
waveform comparator, monitoring both the input and output 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
Figure 16
difference between the two
signal waveforms. When the
difference exceeds 0.3% (equivalent to 0.3% harmonic distortion), the Power Guard activates the PG light and a dynamic electronic attenuator at the amplifier input reduces
the input volume just enough
With Power Guard
to prevent any further
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 preserved. The MC205 Power
Amplifier with Power Guard
is not limited to just the
rated power output, but will
Figure 17
actually produce distortion
free output well above its rated power due to the McIntosh
philosophy of conservative design.
Power Supply Circuits
To compliment the design of the MC205, there is a high
current power supply for the five power amplifier channels.
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 McIntosh Potted
Enclosures
and weighs
over
12.06kg.
The super
size main
filter
capacitors
can store
over 310
Joules of
energy for
Figure 19
the five
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 Control 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).
Block Diagram
of the
Power Supply
Figure 18
17
Specifications
Specifications
Power Output
Minimum sine wave continuous average power output per
channel, all channels operating is:
200 watts into a 4 ohm or 8 ohm load
Output Load Impedance
8 and 4 ohms
Rated Power Band
20Hz to 20,000Hz
Total Harmonic Distortion
0.005% maximum harmonic distortion at any power level
from 250 milliwatts to rated power, 20Hz to 20,000Hz
Dynamic Headroom
1.7dB
Frequency Response
+0, -0.25dB from 20Hz to 20,000Hz
+0, -3dB from 10Hz to 100,000Hz
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
Power Requirements
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
Note: Refer to the rear panel of the MC205 for the correct
voltage.
Overall Dimensions
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
Weight
81 pounds (44.2 kg) net, 114 pounds (51.8 kg) in shipping
carton
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)
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
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 Laboratory. Please see the Part List for the correct part numbers.
Quantity Part Number Description
1 034052 Shipping carton top
1 034051 Shipping carton bottom
2 034054 Foam Pad (top and bottom)
2 034186 Foam Pad (front and rear)
2 034187 Foam Pad (sides)
1 034136 Inner carton top
1 034137 Inner carton bottom
1 034188 Foam Pad (inner carton)
1 034264 Shipping skid
4 101212 1/4 - 20x2-1/4 cap screw
4 104058 Flat washer
19
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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