McIntosh MC202 User manual

McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 139 3-2699 Phone: [phone] FAX: [phone]
Owners
Manual
MC202
MC202 Power Amplifier

2
IMPORTANT SAFETY
INSTRUCTIONS!
PLEASE READ THEM BEFORE
OPERATING THIS EQUIPMENT.
WARNING - TO REDUCE RISK OF
FIRE OR ELECTRICAL SHOCK, DO
NOT EXPOSE THIS EQUIPMENT TO
RAIN OR MOISTURE.
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.
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.
The e clamation point within an equi-
lateral triangle is intended to alert the
user to the presence of important
operating and maintenance (servic-
ing) instructions in the literature ac-
companying the appliance.
General:
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Warning: To reduce risk of fire or electrical shock,
do not expose this equipment to rain or moisture.
This unit is capable of producing high sound pres-
sure levels. ontinued exposure to high sound pres-
sure levels can cause permanent hearing impair-
ment or loss. User caution is advised and ear protec-
tion is recommended when playing at high volumes.
6. aution: to prevent electrical shock do not use this
(polarized) plug with an extension cord, receptacle
or other outlet unless the blades can be fully in-
serted to prevent blade exposure.
Attention: pour pevenir les chocs elecriques pas
utiliser cette fiche polarisee avec un prolongateur,
une prise de courant ou un autre sortie de courant,
sauf si les lames peuvent etre inserees afond ans en
laisser aucune partie a decouvert.
7. Unplug this equipment during lightning storms or
when unused for long periods of time.
. Only use attachments/accessories specified by the
manufacturer.
Installation:
9. The equipment shall be installed near the AC Socket
Outlet and the disconnect device shall be easily acces-
sible.
10. Do not block any ventilation openings. Install in accor-
dance with the manufacturers instructions.
11. Do not install near any heat sources such as radiators,
heat registers, stoves, or other equipment (including
amplifiers) that produce heat.
12. Do not use this equipment near water.
13. 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.
14. Use only with the cart, stand, tripod,
bracket, or table specified by the manu-
facturer, or sold with the equipment.
When a cart is used, use caution when
moving the cart/equipment combination
to avoid injury from tip-over.
onnection:
15. Connect this equipment only to the type of AC power
source as marked on the unit.
16. Protect the power cord from being walked on or
pinched particularly at plugs, convenience receptacles,
and the point where they exit from the equipment.
17. Do not defeat the safety purpose of the polarized or
grounding-type plug.

3
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.
1 . Do not overload wall outlets, extension cords or inte-
gral convenience receptacles as this can result in a risk
of fire or electric shock.
19. To completely disconnect this equipment from the AC
Mains, disconnect the power supply cord plug from the
AC receptacle.
are of Equipment:
20. Clean only with a dry cloth.
21. Do not permit objects or liquids of any kind to be
pushed, spilled and/or fall into the equipment through
enclosure openings.
22. Unplug the power cord from the AC power outlet
when left unused for a long period of time.
Repair of Equipment:
23. Refer all servicing to qualified service personnel. Ser-
vicing is required when the equipment has been dam-
aged in any way, such as power-supply cord or plug is
damaged, liquid has been spilled or objects have fallen
into the equipment, the equipment has been exposed to
rain or moisture, does not operate normally, or has
been dropped.
24. Do not attempt to service beyond that described in the
operating instructions. All other service should be re-
ferred to qualified service personnel.
25. When replacement parts are required, be sure the ser-
vice technician has used replacement parts specified by
McIntosh or have the same characteristics as the origi-
nal part. Unauthorized substitutions may result in fire,
electric shock, or other hazards.
26. Upon completion of any service or repairs to this prod-
uct, ask the service technician to perform safety checks
to determine that the product is in proper operating
condition.
Customer Service
Technical Assistance
Please Take A Moment
Thank You
Copyright 2000 ã by McIntosh Laboratory, Inc.
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:
Your decision to own this McIntosh MC202 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.
Serial Number:
Purchase Date:
Dealer Name:
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 as-
sistance 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]
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 addi-
tional help concerning a suspected problem, you can re-
ceive technical assistance for all McIntosh products at:
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, New York 13903
Phone: [phone]
Fax: [phone]

4
Performance eatures
Introduction and Performance eatures
Introduction
·Power Output
The MC202 consists of two separate power amplifier chan-
nels, each capable of 200 watts into 2, 4 or ohm speakers
with less than 0.005% distortion.
·High urrent Output
A peak output current of 50 amperes per channel ensures
that the MC202 will successfully drive high quality loud-
speakers such as McIntosh for a truly exciting sound expe-
rience.
·Power Guard
Both channels include the patented McIntosh Power Guard
circuit that prevents the amplifier from being overdriven
into clipping, with its harsh distorted sound that can also
damage your valuable loudspeakers.
·Sentry Monitor and Thermal Protection
McIntosh Sentry Monitor power output stage protection
circuits ensure the MC202 will have a long and trouble free
operating life. Built-in Thermal Protection Circuits guard
against overheating.
·Patented Autoformers
McIntosh designed and manufactured Output Autoformers
provide an ideal match between the amplifier output stages
and speaker loads of 2, 4 and ohms. The Autoformers
also provide perfect DC protection for your valuable loud-
speakers.
·Illuminated Power Meters
The Illuminated Power Output Meters on the MC202 are
peak responding, and indicate the power output of the am-
plifier. The Peak Watt Hold Mode allows the meters to
temporarily stay at the highest power output and then
slowly decay.
Now you can take advantage of traditional McIntosh stan-
dards of excellence in the MC202 Power Amplifier. Two
200 watt high current output channels will drive any high
quality loudspeaker system to its ultimate performance.
The MC202 reproduction is sonically transparent and abso-
lutely accurate. The McIntosh Sound is The Sound of the
Music Itself.
Table of Contents
Safety Instructions ............................................................ 2
Thank You and Please Take a Moment............................. 3
Technical Assistance and Customer Service .................... 3
Table of Contents and General Notes ............................... 4
Introduction ...................................................................... 4
Performance Features ....................................................... 4
Dimensions ....................................................................... 5
Installation ........................................................................ 6
Rear Panel Connections and Switch ................................. 7
How to Connect for Stereo ...............................................
How to Connect for Mono .............................................. 10
Front Panel Displays and Controls ................................. 12
How to Operate ............................................................... 13
Technical Description ..................................................... 14
Notes ............................................................................... 17
Specifications ................................................................. 1
Packing Instruction ......................................................... 19
General Notes
1. The following Connecting Cable is available from the
McIntosh Parts Department:
Power Control Cable Part No. 170-202
Six foot, conductor shielded, with two 1/8 inch stereo
mini phone plugs.
. For additional connection information, refer to the owners
manual(s) for any component(s) connected to the MC 0 .
3. The MC 0 mutes the speaker outputs for approximately two
seconds when first turned on.
4. It is very important that loudspeaker cables of adequate size
be used, so that there will be no power loss. 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. m) or less,
use at least 1 Gauge.
5. Pin configuration for the XLR Balanced Input connectors on
the MC 0 : PIN 1: Shield or ground
PIN : + input
PIN 3: - input
6. In the event that the MC 0 over heats, 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 MC 0 has returned to a safe operating
temperature, normal operation will resume.

5
MC202 Dimensions
The following dimensions can assist in determining the
best location for your MC202. There is additional informa-
tion on the next page pertaining to installing the MC202
into cabinets.
MC202 Dimensions
17- 1/2 "
44.45cm
4- 5/8 "
11.75cm
6"
15.24cm
17"
43.18cm
18- 3/4 "
47.62cm
3/16 "
0.48cm
4- 13/16 "
27.30cm
14"
35.56cm
1"
2.54cm
13- 1/4 "
33.65cm
17"
43.18cm
5/8 "
1.59cm
Front View of the MC202
Rear View of the MC202
Side View of the MC202
5- 7/16 "
13.81cm
13/16 "
2.06cm

6
Installation
The MC202 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 MC202 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 MC202 is removed from the custom instal-
lation and used free standing. It also can be custom in-
stalled in a piece of furniture or cabinet of your choice The
required panel cut-
out, ventilation cut-
out and unit dimen-
sions are shown.
Always provide
adequate ventilation
for your MC202.
Cool operation en-
sures the longest
possible operating
life for any elec-
tronic instrument.
Do not install the
MC202 directly
above a heat gener-
ating component
such as a high pow-
ered amplifier. If all
the components are
installed in a single
cabinet, a quiet run-
ning ventilation fan
can be a definite
asset in maintaining
all the system com-
ponents at the
coolest possible op-
erating temperature.
A custom cabi-
net installation
should provide the
following minimum
spacing dimensions
for cool operation.
Allow at least 6
inches (15.24 cm)
above the top, 2
inches (3. 1cm) be-
low the bottom and
Installation
4- 7/8 "
12.38cm
17 - 1/16 "
43.34cm
Cutout Opening for Custom Mounting
MC202 Front Panel
Custom Cabinet Cutout
6"
15.24cm
16"
40.64cm
13 - 1/2 "
34.29cm
15-1 /16 "
38.26cm
25/32 "
1.98cm
Cutout Opening
for Ventilation
Cutout Opening for Ventilation
Support
Shelf
Cabinet
Front
Panel
Chassis
Spacers
Opening
for Ventilation
MC202 Side View
in Custom Cabinet
MC202 Bottom View
in Custom Cabinet
1 "
2.54cm
1 inch (2.54 cm) on each side of the amplifier, so that air-
flow is not obstructed. Allow 20 inches (50. cm) depth
behind the front panel. Allow 1 inch (2.54 cm) in front of
the mounting panel for knob clearance. Be sure to cut out a
ventilation hole in the mounting shelf according to the di-
mensions in the drawing.

7
UNBALANCED INPUTS
for audio cables from a
preamplifier or control
center audio outputs
MC202 Rear Panel Connections and Switch
Connect the MC 0
power cord to a live
AC outlet. Refer to
information on the
back panel to deter-
mine the correct
voltage
BALANCED INPUTS
for audio cables from a
preamplifier or control
center audio outputs
POWER CONTROL IN
receives turn on/off sig-
nals from a McIntosh
component and the
POWER CONTROL OUT
sends that turn on/off sig-
nal to the next McIntosh
component
MODE switch selects
STEREO or MONO
BRIDGE modes of
operation
Main Fuse holder,
refer to information
on the back panel
of your MC 0 to
determine the cor-
rect fuse size and
rating
RIGHT OUTPUT
Connections for
, 4 or 8 ohm
loudspeakers
LEFT OUTPUT
Connections for
, 4 or 8 ohm
loudspeakers

8
How to Connect the MC202 for Stereo
Caution: The supplied AC Power Cord should not be
connected to the Rear Panel of the C202
Amplifier until after the Loudspeaker Connections
have been made and the supplied protective
Terminal Connection Covers has been installed.
Failure to observe this could result in Electric
Shock.
1. For Remote Power Control, connect a power control
cable from the Control Center or Preamplifier Power
Control Out to the MC202 Power Control In.
2. Connect cables from the Balanced Outputs of a McIn-
tosh Preamplifier or Control Center to the MC202 Bal-
anced Inputs.
Note: An optional hookup is to use unbalanced cables.
3. Prepare the Loudspeaker Hookup Cables that attach to
the MC202 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 to-
gether 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.
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 ter-
minal
cap un-
til the
cable is
firmly
clamped
into the terminal so the wires cannot
slip out. Refer to figures 4, 5 & 6.
Banana plug connection:
Insert the banana plug into the hole at the top of the
terminal. Tighten the top portion of the terminal post
and the set screw to secure the banana plug in place.
Note: The use of Banana Plugs is for use in the United
States and Canada only.
4. Connect the loudspeaker hookup cables to the output
terminals that match the impedance of your loudspeak-
ers, being careful to observe the correct polarities. Out-
put impedance connections of 2 ohms, 4 ohms and
ohms are provided. If the impedance of your loud-
speakers is in-between the available connections, use
the nearest lower impedance connection.
WARNING: Loudspeaker terminals are hazardous live
and present a risk of electric shock. For
additional instruction on making
Loudspeaker Connections contact your
cIntosh Dealer or cIntosh Technical
Support.
5. Attach the supplied Terminal Connection Covers with
the four Pan Head Mounting
Screws (6-32 x 5/16 inch) to
the Rear Panel of the MC202
Amplifier. Refer to figures 7
and .
Note: There are four openings
on the bottom edge of the
cover to allow for the
Loudspeakers Cable to
exit the MC 0 .
6. Connect the MC202 power cord to an active AC outlet.
Figure 7
Terminal Connection Covers
Cable
Openings
Cable
Openings
Figure 8

9
McIntosh C41 Preamplifier
To AC Outlet
How to Connect the MC202 for Stereo
Right
Loudspeaker
4 ohm
Left
Loudspeaker
4 ohm

1
How to Connect the MC202 for Mono Bridge
Caution: The supplied AC Power Cord should not be
connected to the Rear Panel of the C202
Amplifier until after the Loudspeaker Connections
have been made and the supplied protective
Terminal Connection Covers has been installed.
Failure to observe this could result in Electric
Shock.
1. For Remote Power Control, connect a power control
cable from the Control Center or Preamplifier Power
Control Out to the MC202 Power Control In.
2. Connect cables from the Balanced Outputs of a McIn-
tosh Preamplifier or Control Center to the MC202 Bal-
anced Input.
Note: An optional hookup is to use unbalanced cable.
3. Prepare the Loudspeaker Hookup Cables that attach to
the MC202 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 to-
gether 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.
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 ter-
minal
cap un-
til the
cable is
firmly
clamped into the terminal so the
wires cannot slip out. Refer to fig-
ures 4, 5 & 6.
Banana plug connection:
Insert the banana plug into the hole at the top of the
terminal. Tighten the top portion of the terminal post
and the set screw to secure the banana plug in place.
Note: The use of Banana Plugs is for use in the United
States and Canada only.
4. Connect the loudspeaker hookup cables to the output
terminals that match the impedance of your loudspeak-
ers, being careful to observe the correct polarities. Out-
put impedance connections of 4 ohms, ohms and 16
ohms are provided. If the impedance of your loud-
speaker is in-between the available connections, use
the nearest lower impedance connection.
WARNING: Loudspeaker terminals are hazardous live
and present a risk of electric shock. For
additional instruction on making
Loudspeaker Connections contact your
cIntosh Dealer or cIntosh Technical
Support.
5. Attach the supplied Terminal
Connection Covers with the
four Pan Head Mounting
Screws (6-32 x 5/16 inch) to
the Rear Panel of the MC202
Amplifier. Refer to figures 7
and .
Note: There are four openings
on the bottom edge of the
cover to allow for the Loudspeakers Cable to exit
the MC 0 .
6. Connect the MC202 power cord to an active AC outlet.
Figure 7
Terminal Connection Covers
Cable
Openings
Cable
Openings
Figure 8

11
How to Connect the MC202 for Mono Bridge
McIntosh C41 Preamplifier
To AC Outlet
4 ohm
Loudspeaker
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12
MC202 ront Panel Displays and Controls
METER indicates the Left Channel
Power Output of the amplifier
METER Switch selects
the display modes of the
power output meters
POWER GUARD LEDs
light when the amplifier
channel POWER GUARD
circuit activates
POWER Switch Turns
AC power on/off, or on/
remote
Remote On Indicator
indicates when the
amplifier is in the
Remote Turn-On
Mode
METER indicates the Right Channel
Power Output of the amplifier

13
How to Operate the MC202
How to Operate the MC202
Power On
To have the MC202 automatically turn On or Off when a
control center turns on or off, rotate the power switch to the
remote position. For manual operation, rotate the power
switch to the on or off position
as desired. Refer to figure 9.
Note: There must be a power
control connection between
the MC 0 and the
McIntosh Control Center,
in order for the remote
power turn-on to function.
Meter Selection
Rotate the meter mode switch to select the meter operation
mode you desire. Refer to figures 10 and 11.
Lights Off - Meter lights are turned off and the meters will
continue to indicate
the power output.
Watts- The meters respond
to all the musical
information being
produced by the
amplifier. They in-
dicate to an accu-
racy of at least 95%
of the power output with only a single cycle
of a 2000Hz tone burst.
Hold - The meter pointer is locked to the highest
power peak in a sequence of peaks. It is elec-
tronically held to this power level until a
higher power peak passes through the ampli-
fier. The meter pointer will then rise to the
newer
higher indi-
cation. If
no further
power
peaks are
reached,
the meter pointer will very slowly return to its
rest position or lower power level. The decay
rate is approximately 6 dB per minute.
Note: The MC 0 Power Output Meters
indicate the wattage delivered to the
loudspeakers. When in Mono Bridge
Mode, the actual power output is a
combination of both the Right and Left
Meter Indications.
Mode Switch
The Mode Switch, which is located on
the Rear Panel of the MC202, allows
you to select either STEREO or
MONO BRIDGE Modes of Operation.
Refer to figure 12.
Note: There is additional information
pertaining to both modes of
operation How to Connect on
pages 8 and 9.
Figure 11
Figure 9
Figure 12
Figure 1

14
Technical Description
McIntosh Laboratory, the company who introduced the
worlds first amplifier that could be called High Fidelity,
has done it again. The McIntosh engineering staff has cre-
ated a power amplifier without compromise, using the most
advanced McIntosh circuit design concepts.
A continuous average power output rating of 200 watts
and with an output current of greater than 50 amperes per
channel, making this one of the most advanced and power-
ful amplifier McIntosh has ever manufactured. The distor-
tion limits for the MC202 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 MC202 are so
low, it takes special measuring techniques to make accurate
readings. The MC202 can deliver the best possible perfor-
mance from any type of high quality loudspeaker system.
Creating an amplifier with this level of performance did
not come easily. Many months of design, testing and mea-
suring were required. Extensive controlled listening tests,
the ultimate form of measuring, were made before the final
design was accepted.
Design Philosophy
The design philosophy incorporated in the MC202 in-
volved several different techniques, all based on sound sci-
entific logic. Refer to figure 13. Every stage of voltage or
current amplification must be as linear as possible prior to
Inside of the MC2 2
Figure 13
Block Diagram of the Amplifer and Meter Circuitry
the use of negative feedback. McIntosh engineers know
how to properly design negative feedback circuits so they
contribute to the extremely low distortion performance ex-
pected from a McIntosh amplifier. The typical McIntosh

15
Technical Description
Figure 14
Figure 15
owner would never accept the approximately 100 times
higher distortion of many non-feedback designs.
All transistors are selected to have nearly constant cur-
rent gain over the entire current range they must cover.
Output transistors in particular, have matched uniform cur-
rent gain, high current-bandwidth product and large active
region safe operating area. An automatic tracking bias sys-
tem completely eliminates any trace of crossover distor-
tion. Precision metal film resistors and low dielectric ab-
sorption film capacitors are used in all critical circuit loca-
tions.
The output signal of the circuit is coupled together in
the unique McIntosh MC202 Output Autoformer. It pro-
vides low distortion power transfer at frequencies from be-
low 20Hz to well beyond 20,000Hz with optimum imped-
ance points of two ohms, four ohms and eight ohms. The
unequaled expertise of McIntosh in the design and manu-
facturing of autoformers is legendary in the high fidelity
industry.
The high efficiency circuit design of the MC202 con-
tributes to low operating temperatures. More than 621
square inches of heat sink area keep the MC202 operating
safely with convection cooling. No fans are needed.
Autoformers
All solid state power amplifier output circuits work best
into what is called an optimum load. This optimum load
may vary considerably from what a loudspeaker requires.
In the case of more than one loudspeaker connected in par-
allel, the load to the power amplifier may drop to two ohms
or even less. A power amplifier connected to a load that is
lower than optimum, causes more output current to flow,
which results in extra heat being generated in the power
output stage. This increase in temperature will result in a
reduced life expectancy
for the amplifier.
The Autoformer cre-
ates an ideal match be-
tween the power ampli-
fier output stage and the
loudspeaker. Refer to
figure 14. There is abso-
lutely no performance
limitation with an
Autoformer. Its fre-
quency response ex-
ceeds that of the output
circuit itself, and ex-
tends well beyond the
Figure 17
With Power Guard
Figure 18
Without Power Guard
Figure 16
Input Test Signal
audible range. Its distortion level is so low it is virtually
impossible to measure. In the rare event of a power ampli-
fier output circuit failure, the McIntosh Autoformer pro-
vides absolute protection from possible damage to your
valuable loudspeakers.
Protection ircuits
The MC202 incorporates its ver-
sion of the McIntosh Sentry Moni-
tor output transistor protection cir-
cuit. Refer to figure 15. There is ab-
solutely no compromise in sonic
performance with this circuit, and it
ensures safe operation of the ampli-
fier under even the most ex-
treme operating conditions. The
different types of protection cir-
cuits incorporated in the
MC202 insure a long and safe
operating life.
The MC202 also includes
the unique patented McIntosh
Power Guard circuit. Power
Guard eliminates the possibility
of ever overdriving the ampli-
fier into clipping. Refer to fig-
ures 16, 17 and 1 . An
overdriven amplifier can pro-
duce both audible and inaudible
distortion levels exceeding
40%. The audible distortion is
unpleasant to hear, but the inau-
dible ultrasonic distortion is
also undesirable, since it can
damage valuable loudspeaker
system tweeters. You will never
experience the harsh and dam-
aging distortion due to clipping.
The Power Guard circuit is a
waveform comparator, monitor-
ing both the input and output
waveforms. Under normal oper-
ating conditions, there are no
differences between the shape
of these waveforms. If an ampli-
fier channel is overdriven, there
will be a difference between the
two signal waveforms. When
the difference exceeds 0.3%

16
(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
to prevent any further increase in distortion. The Power
Guard circuit acts so fast that there are absolutely no au-
dible side effects and the sonic purity of the music repro-
duction is perfectly preserved. The MC202 Power Ampli-
fier with Power Guard is not limited to just the rated power
output, but will actually produce distortion free output well
above its rated power due to the McIntosh philosophy of
conservative design.
Power Supply ircuits
To compliment the design of the MC202, there is a high
voltage power supply for both channels. Refer to figure 19.
The power amplifiers draw high current from the AC
power line. Therefore, it is important that they plug directly
into the wall outlet.
Also, most owners desire that there be one power
switch for the whole audio system. The MC202 is equipped
with a circuit that provides remote Power Control from
your McIntosh Preamplifier or Control Center. When you
turn on your preamplifier a digital 1 (+5V) signal oper-
ates the power relay in the MC202. The MC202 also has a
remote Power Control Out Jack. The Power Control signal
from this jack is delayed by a fraction of a second so that
the turn on power surge of the next power amplifier occurs
at a later time. This helps prevent power circuit overload
that could trip circuit breakers or blow fuses, a very impor-
tant feature in a high power Home Theater System employ-
ing three MC202 Power Amplifiers.
The MC202 can provide greater than 50 amperes peak
output current to drive uneven speaker loads. Some poor
speaker designs have input impedance that dip to 1 or 2
ohms at various frequencies and the MC202 has the output
current reserve to drive them. The MC202 has main filter
capacitors that guarantee an excellent signal to noise ratio
and the energy storage necessary for the wide dynamic
range that Digital Audio demands.
Figure 19
Block Diagram of the Power Supply

17
Notes

18
Specifications
Specifications
Power Output Stereo
Minimum sine wave continuous average power output per
channel, all channels operating is:
200 watts into 2 ohm load
200 watts into 4 ohm load
200 watts into ohm load
Power Output Mono
Minimum sine wave continuous average power output per
channel, all channels operating is:
400 watts into 4 ohm load
400 watts into ohm load
400 watts into 16 ohm load
Rated Power Band
20Hz to 20,000Hz
Total Harmonic Distortion
Maximum Total Harmonic Distortion at any power
level from 250 milliwatts to rated power output is:
0.005% for 2, 4 or ohm loads (Stereo)
0.005% for 4, or 16 ohm loads (Mono)
Dynamic Headroom
1.9dB
Frequency Response
+0, -0.25dB from 20Hz to 20,000Hz
+0, -3dB from 10Hz to 100,000Hz
Sensitivity
1.7Volt unbalanced inputs
3.4Volt balanced inputs
A-Weighted Signal To Noise Ratio
110dB (1.7V)
Intermodulation Distortion
Maximum Intermodulation Distortion if instanta-
neous peak output per channel does not exceed
twice the rated output, for any combination of fre-
quencies from 20Hz to 20,000Hz, with all channels
operating is:
0.005% for 2, 4 or ohm loads (Stereo)
0.005% for 4, or 16 ohm loads (Mono)
Input Impedance
10,000 ohms balanced or unbalanced inputs
Wide Band Damping Factor
Greater than 40
Power Requirements
100 Volts, 50/60Hz at 4. amps
110 Volts, 50/60Hz at 4.4 amps
120 Volts, 50/60Hz at 4.0 amps
220 Volts, 50/60Hz at 2.2 amps
230 Volts, 50/60Hz at 2.1 amps
240 Volts, 50/60Hz at 2.0 amps
Note: Refer to the rear panel of the MC 0 for the correct
voltage.
Dimensions
Front Panel: 17-1/2 inches (44.45cm) wide, 5-7/16 inches
(13. 1cm) high. Depth behind front mounting panel is 1
inches (45.72cm). Clearance required in front of the Front
Panel is 1 inch (2.54cm) for knobs.
Weight
65 pounds (29.49 Kg) net, 3 pounds (37.65 Kg) in ship-
ping carton

19
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 three plastic feet are at-
tached to the bottom of the equipment. Three #10 x 2-1/2
inch screws and washers must be used to fasten the unit
securely to the bottom pad and wood 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
1 033 3 Shipping carton only
2 033 37 End cap (Foam pad)
1 033 36 Inside carton only
1 033725 Top Pad
1 03400 Bottom pad
3 01721 Plastic foot (spacer)
1 033699 Wood skid
3 101169 #10 x 2-1/2 inch Wood screw
3 104033 #10 x 1-3/4 inch Flat washer
4 01721 Plastic foot
4 100159 #10-32 x 3/4 inch Machine
screw
4 1040 3 #10 x 7/16 inch Flat washer
1 049107 Shipping carton complete with
all the above parts

McIntosh Part No. 04067301
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, NY 13903