McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 www.mcintoshlabs.

com

MC462
Quad Balanced
Power Amplifier
Owner’s Manual
 Important Safety Information is supplied in a separate document “Important Additional Operation Information Guide”
Thank You Customer Service General Information
Your decision to own this McIntosh MC462 Stereo If it is determined that your McIntosh product is in 1. For additional connection information, refer to the
Power Amplifier with Quad Balanced Circuitry ranks need of repair, you can return it to your Dealer. You owner’s manual(s) for any component(s) connected
you at the very top among discriminating music listen- can also return it to the McIntosh Laboratory Service to the MC462.
ers. You now have “The Best.” The McIntosh dedica- Department. For assistance on factory repair return 2. The MC462 mutes the speaker output for approxi-
tion to “Quality,” is assurance that you will receive procedure, contact the McIntosh Service Department mately two seconds when first turned on.
many years of musical enjoyment from this unit. at: 3. For the best performance and safety it is important
Please take a short time to read the information in McIntosh Laboratory, Inc. to always match the impedance of the Loudspeaker
this manual. We want you to be as familiar as pos- 2 Chambers Street to the Power Amplifier connections. Refer to “How
sible with all the features and functions of your new Binghamton, New York 13903 to Connect” pages 7 thru 10.
McIntosh. Phone: 607-723-3515 Note: The impedance of a Loudspeaker actually var-
ies as the Loudspeaker reproduces different
Please Take A Moment Fax: 607-723-1917
frequencies. As a result, the nominal impedance
The serial number, purchase date and McIntosh Dealer Table of Contents rating of the Loudspeaker (usually measured at
name are important to you for possible insurance a midrange frequency) might not always agree
Safety Instructions...................................................... 2 with the impedance of the Loudspeaker at low
claim or future service. The spaces below have been
(Separate Sheet).................... Important Additional frequencies where the greatest amount of power
provided for you to record that information:
Operation Information Guide is required. Contact the Loudspeaker Manufac-
Serial Number:________________________________ Thank You and Please Take a Moment........................ 2 turer for additional information about the actual
Technical Assistance and Customer Service............... 2 impedance of the Loudspeaker before connecting
Purchase Date:________________________________ Table of Contents......................................................... 2 it to the McIntosh MC462.
General Information.................................................... 2 4. In the event the MC462 over heats, due to improper
Dealer Name:_________________________________
Connector and Cable Information...............................3 ventilation and/or high ambient temperature, the
Technical Assistance Introduction..................................................................3 protection circuits will activate. The Front Panel
Performance Features..................................................3 Power Guard LED will continuously indicate ON
If at any time you have questions about your McIntosh and the audio will be muted. When the MC462 has
Dimensions..................................................................5
product, contact your McIntosh Dealer who is familiar returned to a safe operating temperature, normal
Installation...................................................................6
with your McIntosh equipment and any other brands operation will resume.
Rear Panel Connections and Switch............................7
that may be part of your system. If you or your Dealer 5. When discarding the unit, comply with local rules
Output Terminals and How to Connect................... 8-9
wish additional help concerning a suspected problem, or regulations. Batteries should never be
Output Terminals and How to Connect
you can receive technical assistance for all McIntosh thrown away or incinerated but disposed
for Bi-Amp.......................................................... 10-11
products at: of in accordance with the local regulations
Front Panel Displays and Controls.............................12
How to Operate.......................................................... 13 concerning battery disposal.
McIntosh Laboratory, Inc. 6. For additional information on the MC462 and
Technical Description........................................... 14-17
2 Chambers Street other McIntosh Products please visit the McIntosh
Specifications............................................................. 18
Binghamton, New York 13903 Website at www.mcintoshlabs.com.
Packing Instruction.................................................... 19
Phone: 607-723-3512
Fax: 607-724-0549 Copyright 2018 © by McIntosh Laboratory, Inc.
2
 Cable Information, Introduction and Performance Features

Connector and Cable Information Performance Features

XLR Connectors • Power Output trouble free operating life. Built-in Thermal Protection
Below is the Pin configuration for the XLR Balanced The MC462 is a Power Amplifier with a capability Circuits guard against overheating.
Input, Input/Output Connectors on the MC462. Refer of 450 watts per channel into 2, 4 or 8 ohm speakers
IN OUT
to the diagram for connection: with less than 0.005% distortion. The Power Amplifier • Special Power Supply
PIN 1: Shield/Ground Circuitry uses Thermal Trak1 Output Transistors for A very large Power Transformer and Large Capaci-
PIN 2: + Input/Output lower distortion and cool operation. tors ensure stable noise free operation even though the
PIN 3: - Input/Output PIN 2 PIN 1 PIN 1
PIN 3
PIN 2 power line varies.
PIN 3
• Quad Balanced Circuitry
Power Control Connector The MC462 is fully balanced from input to output. It • Illuminated Power Meters
The MC462 Power Control Input receives an On/Off consists of two matched power amplifiers operating The Illuminated Power Output Watt Meters on the
signal from +5 to +12 volts. The Power Control Output in push-pull with their outputs combined in a McIn- MC462 are peak responding, and indicate the true
will in turn provide a +12 volt tosh Autoformer. The Quad Balanced configuration power output of the amplifier. The Peak Watt Hold
Output Signal with a total cur- Trigger cancels virtually all distortion. Mode allows the meters to temporarily stay at the
rent up to 50mA. An additional Control highest power output and then slowly decay. The Front
Meter
connection is for controlling Illumination • Patented Autoformer Panel Meter Illumination may be switched Off at any
the illumination of the MC462 Control Ground McIntosh designed and manufactured Output Auto- time.
Power Output Meters. The 1/8 formers provide an ideal match between the amplifier
inch stereo mini phone plug connects to a McIntosh output stages and speaker loads of 2, 4 and 8 ohms. • McIntosh Custom Binding Posts
Preamplifier or A/V Control Center Power Control The Autoformers also provide perfect DC protection McIntosh patent pending gold plated output terminals
Output. for your valuable loudspeakers. deliver high current output. They accept large diam-
eter wire and spade lugs. Banana plugs may also be
Output Terminal Connector • Balanced and Unbalanced Inputs used only in the United States and Canada.
When cables with spade lugs are used Balanced connections guard against induced noise and
for Loudspeaker Connection, the spade allow long cable runs without compromising sound • Glass Front Panel and Super Mirror Chassis
lugs need an opening of at least 3/10 inch quality. Finish
(7.6mm). 3/10 of an inch The famous McIntosh Illuminated Glass Front Panel
(7.6millimeters)
• Power Guard uses long life Light Emitting Diodes (LEDs) and
The patented McIntosh Power Guard circuit prevents the Stainless Steel Chassis with Super Mirror Fin-
Introduction the amplifier from being over driven into clipping, ish ensures the pristine beauty of the MC462 will be
Now you can take advantage of traditional McIntosh with its harsh distorted sound that can also damage retained for many years.
standards of excellence in the MC462 Stereo Power your valuable loudspeaker.
Amplifier with Quad Balanced Circuitry. The 450
watts high current output per channel will drive any • Sentry Monitor and Thermal Protection
high quality Loudspeakers. The MC462 reproduction McIntosh Sentry Monitor power output stage protec-
is sonically transparent and absolutely accurate. The tion circuits ensure the MC462 will have a long and
McIntosh Sound is “The Sound of the Music Itself”. 1
ThermalTrak™ and ON Semiconductor are trademarks of Semi-
conductor Components Industries, LLC
3
 Dimensions

Dimensions
The following dimensions can assist in determining
the best location for your MC462.

Front View of the MC462

17-1/2"
44.5cm

8-7/8" 9-7/16" Side View of the MC462

22.5cm
24.0cm

20-1/2"
52.1cm

16-5/8"
42.2cm

Rear View of the MC462

8-3/8"
16-13/16" 3/16" 21.3cm
42.7cm 0.5cm

2-1/4" 12-1/2" 2-3/16"

5.7cm 31.8cm 5.6cm
DISABLED

11-3/4"
29.9cm

4
 Installation

Installation 17"
The MC462 can be placed upright on a table or 43.18cm
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 Opening for Ventilation

of the MC462 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 MC462 Front Panel 14-11/16"
MC462 is removed from the custom installation and Custom Cabinet Cutout 37.30cm
used free standing. The required panel cutout, ventila-
tion cutout and unit dimensions are shown.
Always provide adequate ventilation for your MC462.
Cool operation ensures the longest possible operating
life for any electronic instrument. Do not install the
MC462 directly above a heat generating component Cabinet Front Panel Cutout Opening for Custom Mounting
such as a high powered amplifier. If all the compo- 6"
nents are installed in a single cabinet, a quiet running Cabinet 15.24cm
Front
ventilation fan can be a definite asset in maintaining Panel
all the system components at the coolest possible oper- Opening
for Ventilation
ating temperature.
A custom cabinet installation should provide the fol-
lowing minimum spacing dimensions for cool opera- MC462 Side View
tion. in Custom Cabinet
Allow at least 6 inches (15.24cm) above the top, 2
inches (5.08cm) below the bottom, 3 inches (7.62cm)
Cutout Opening for Ventilation
behind the rear panel and 2 inches (5.08cm) on each
Chassis
side of the Power Amplifier, so that airflow is not Support
2-1/2" Spacers
Shelf
obstructed. Allow 2-1/2 inches (6.35 cm) in front of 6.35cm
the mounting1 panel for clearance. Be sure to cut out
a ventilation hole in the mounting shelf according
to the dimensions in the drawing. MC462 Bottom View 12-3/4"
32.38cm
in Custom Cabinet
1
When the MC462 is installed together with other McIn- 16"
40.64cm
tosh Components, check clearances on all components Cutout Opening
before proceeding. for Ventilation

Note: Center the cutout Horizontally

on the unit. For purposes of
clarity, the above illustration
is not drawn to scale.

5
 Rear Panel Connections and Switch

Unbalanced INput (RIGHT Channel) for an Unbalanced INput (LEFT Channel) for an au-
audio cable from a Preamplifier or A/V Con- dio cable from a Preamplifier or A/V Control
Balanced OUTputs (LEFT and trol Center audio output. Balanced INputs (LEFT Center audio output.
RIGHT Channels) for an audio Unbalanced OUTput (RIGHT Channel) for an and RIGHT Channels) for Unbalanced OUTput (LEFT Channel) for an
cable to the next Power Ampli- audio cable to the next Power Amplifier Input audio cables from a Pre- audio cable to the next Power Amplifier Input
fier Input amplifier or A/V Control POWER CONTROL IN
Center audio output receives turn On/Off
signals from a McIntosh
INPUT MODE switch se-
component.
lects between BALANCED
POWER CONTROL OUT
or UNBALANCED Inputs
1 and 2 send turn On/Off
signals to the next McIn-
tosh Component

DISABLED

RIGHT OUTPUTS RIGHT OUTPUTS Fuse holder, refer to LEFT OUTPUTS LEFT OUTPUTS
Connection for a 2 Connection for an 8 information on the rear Connection for an 8 Connections for a 2
ohm Loudspeaker ohm Loudspeaker panel of your MC462 to ohm Loudspeaker ohm Loudspeaker
determine the correct
fuse size and rating

RIGHT OUTPUTS Connect the MC462 power AUTO OFF Mode LEFT OUTPUTS
Connection for a 4 cord to a live AC outlet. Refer Switch selects be- Connection for a 4
ohm Loudspeaker to the rear panel to determine tween ENABLED ohm Loudspeaker
the correct voltage or DISABLED

Caution: The Loudspeaker Negative Connections are above chassis ground. Do not combine any connections together, ground them or connect with another MC462.
6
 Output Terminals and How to Connect

Output Terminals
When connecting the Loudspeaker Hookup Cables to 1. For Remote Power Control, connect a power control Connect a single Loudspeaker only to the Right and
the MC462 Power Amplifier Output Terminals please cable from the Audio Preamplifier or A/V Con- Left Output Terminals.
follow the steps below: trol Center Power Control Output 1 (Trig 1) to the When connecting Loudspeakers to the MC462 it
1. Rotate the top of the Output Terminal Post coun- MC462 POWER CONTROL IN. is very important to use cables of adequate size, so
terclockwise until an opening Notes: 1. When a Power Control Cable is connected there is little to no power loss in the cables. The size is
appears. Refer to figures A and between the MC462 and Preamplifier (or specified in Gauge Numbers or AWG (American Wire
A/V Control Center), the AUTO OFF Fea- Gauge). The smaller the Gauge number, the larger the
B.
ture is bypassed. Refer to page 13. wire size:
2. Insert the Loudspeaker hookup 2. When the MC462 has Loudspeakers con-
cable into the Output Terminal Opening nected to it with a Power Control Input, Loudspeaker Cable Distance vs Wire Gauge Guide
Post opening or the cable spade connect the MC462 Power Control Out 1 Loudspeaker
25 feet 50 feet 100 feet
Figure A Figure B (7.62 meters) (15.24 meters) (30.48 meters)
lug around the center post of and Out 2 to the Loudspeakers. Impedance
or less or less or less
the Output Terminal. Refer to 2. Connect XLR cables from the Balanced Output 1 2 Ohms 12AWG 10AWG 8AWG
figure C. (L&R) of an Audio Preamplifier or A/V Control 4 Ohms 14AWG 12AWG 10AWG
3. Rotate the top of the Output Center to the MC462 Balanced INput (RIGHT and 8 Ohms 16AWG 14AWG 12AWG
Terminal Post clockwise until it LEFT). Place the INPUT MODE Switch in the
is finger tight. Refer to figure D. BALANCED Position. 4. Prepare the Loudspeaker Hookup Cable for attach-
4. Place the supplied McIntosh Note: An optional hookup is to use unbalanced ment to the MC462 Power Amplifier:
Figure C Figure D
Wrench over the top of the Out- cables and place the INPUT MODE Switch in
put Terminal and rotate it one the UNBALANCED Position.
quarter of a turn (90° ) to secure
the Loudspeaker Cable Connec- Figure 2 Figure 3 Figure 4
Remove Screws Remove Screws
tion. Do not over tighten. Refer
to figure E. Figure E
Bare wire cable ends:
Carefully remove sufficient insulation from the
How to Connect cable ends, refer to figures 2, 3 & 4. If the cable
Caution: Do not connect the AC Power Cord to the is stranded, carefully twist the strands together
DISABLED

MC462 Rear Panel until after the Loudspeaker as tightly as possible.

Connections are made and the protective Termi- Notes: 1. If desired, the twisted ends can be tinned
nal Connections Covers are installed. Failure to with solder to keep the strands together.
observe this could result in Electric Shock. Figure 1 2. The prepared bare wire cable ends may be
The connection instructions below, together with the inserted into spade lug connectors.
3. Using a suitable tool remove the four screws from
MC462 Connection Diagram located on the separate 3. Banana plugs are for use in the United
the MC462 Rear Panel and temporarily place them States and Canada only.
folded sheet “Mc1A”, is an example of a typical audio in a safe place. Refer to figure 1.
system. Your system may vary from this, however the This McIntosh MC462 Stereo Power Amplifier with
actual components would be connected in a similar Quad Balanced Circuity is designed for Loudspeak-
manner. For additional information refer to “Connec- ers with an impedance of 2 ohms, 4 ohms or 8 ohms.
tor and Cable Information” on page 3.
7
 Output Terminals and How to Connect

Banana Plugs are for use in the United States and 4Ω (ohms) or 8Ω (ohms) connection to match the 12. Connect the Loudspeaker hookup cables to the
Canada only: impedance of the Loudspeaker, being careful to MC462 Negative Output Terminal and Positive
5. Locate the Terminal Connection Covers from the observe the correct polarities. Output Terminal indentified as 2Ω (ohms), 4Ω
inside of the MC462 shipping carton. Insert the Note: The illustration in figure 5 is connections for (ohms) or 8Ω (ohms) connection to match the
just prepared Loudspeaker hookup cables thru the 8Ω (ohms) Loudspeakers. impedance of the Loudspeaker, being careful to
cover openings, one cover for each channel. Refer If the Loudspeaker’s impedance is in-between observe the correct polarities. Insert the spade
to figure 5. the available connections, use the nearest lower lug connector or prepared section of the cable end
impedance connection. Refer to “General Informa- into the terminal side access hole, and tighten the
tion” Note 4 on page 2 for additional information. terminal cap until the cable is firmly clamped into
Cover Openings Cover Openings
WARNING: Loudspeaker terminals are hazard- the terminals so the lugs or wire cannot slip out.
ous live and present a risk of electric
Refer to fgures 7 and 8.
shock. For additional instruction on
making Loudspeaker Connections con-
tact your McIntosh Dealer or McIn-
DISABLED
tosh Technical Support.
9. Attach the Terminal Connection Covers to the
MC462 Rear Panel with the previously removed Figure 7 Figure 8
Screws. Refer to figure 5.
Cover Screws Cover Screws
10. Connect the MC462 Power Cord to an active AC Note: The illustration in figure 6 is connections for
Figure 5 (Inside USA and Canada)
outlet. 8Ω (ohms) Loudspeakers.
6. Attach the previously prepared bare wire cable ends If the Loudspeaker’s impedance is in-between
into the banana plugs and secure the Spade Lug or Wire Connections:
the available connections, use the nearest lower
connections. Refer to figure F. 11. Locate the Terminal Connections Covers from the
impedance connection. Refer to “General Informa-
7. Rotate the top of the Output Terminal inside of the MC462 shipping carton. Insert the
tion” Note 3 on page 2 for additional information.
Post clockwise until it is finger tight. Figure F
just prepared
Figure HLoudspeaker hookup cables thru the WARNING: Loudspeaker terminals are hazard-
Refer to figure G. Then using the Mc- cover openings, one cover for each channel. Refer ous live and present a risk of electric
Intosh Wrench, rotate the top of the to figure 6. shock. For additional instruction on
Output Terminal one quarter of a turn making Loudspeaker Connections con-
Cover Openings Cover Openings tact your McIntosh Dealer or McIn-
(90° ). Do not over tighten. Refer to
figure E. tosh Technical Support.
8. Referring to figure H, connect the Figure G
13. Attach the Terminal Connections Covers to the
Loudspeaker hookup MC462 Rear Panel with the previously removed
cables with banana plugs Screws. Refer to figure 6.
into the hole at the top 14. Connect the MC462 power cord to an active AC
DISABLED

of the terminal to the outlet.

Figure F Figure H
MC462 Negative Out-
put Terminal and Posi- Cover Screws Cover Screws
tive Output Terminal indentified as 2Ω (ohms), Figure 6 (Outside USA and Canada)

8
 Output Terminals and How to Connect for Bi-Amp

Output Terminals
When connecting the Loudspeaker Hookup Cables to 1. For Remote Power Control, connect a power control
the MC462 Power Amplifier Output Terminals please cable from the Audio Preamplifier or A/V Con- Remove Screws
Remove Screws
follow the steps below: trol Center Power Control Output 1 to the MC462
1. Rotate the top of the Output Terminal Post coun- POWER CONTROL IN Amplifier One.
terclockwise until an opening Note: When a Power Control Cable is connected be-
appears. Refer to figures A and tween the MC462 (Power Amplifier 1) and Pre-
amplifier (or A/V Control Center), the AUTO DISABLED

B.
OFF Feature is bypassed. Refer to page 13.
2. Insert the Loudspeaker hookup
2. Connect a power control cable from Amplifier One
cable into the Output Terminal Opening
Power Control OUTput 1 to the MC462 POWER
Post opening or the cable spade Figure 1
Figure A Figure B CONTROL IN Amplifier Two.
lug around the center post of Note: When the MC462 (Power Amplifier 2) has When connecting Loudspeakers to the MC462 it
the Output Terminal. Refer to Loudspeakers connected to it with a Power is very important to use cables of adequate size, so
figure C. Control Input, then connect the the MC462 there is little to no power loss in the cables. The size is
3. Rotate the top of the Output Power Control Out 1 and Out 2 to the specified in Gauge Numbers or AWG (American Wire
Terminal Post clockwise until it Loudspeakers. Gauge). The smaller the Gauge number, the larger the
is finger tight. Refer to figure D. 3. Connect XLR cables from the Balanced Output 1 wire size:
4. Place the supplied McIntosh (L&R) of an Audio Preamplifier or A/V Control
Figure C Figure D Loudspeaker Cable Distance vs Wire Gauge Guide
Wrench over the top of the Out- Center to the MC462 (Power Amplifier 1) Bal-
25 feet 50 feet 100 feet
put Terminal and rotate it one anced INput (RIGHT and LEFT). Place the INPUT Loudspeaker
(7.62 meters) (15.24 meters) (30.48 meters)
Impedance
quarter of a turn (90° ) to secure MODE Switch in the BALANCED Position. or less or less or less

the Loudspeaker Cable Connec- Note: An optional hookup is to use unbalanced 2 Ohms 12AWG 10AWG 8AWG
tion. Do not over tighten. Refer cables and place the INPUT MODE Switch in 4 Ohms 14AWG 12AWG 10AWG
to figure E. the UNBALANCED Position. 8 Ohms 16AWG 14AWG 12AWG
Figure E
4. Connect XLR cables from the MC462 (Power
6. Prepare the Loudspeaker Hookup Cable for attach-
How to Connect for Bi-Amp Amplifier 1) Audio Balanced OUTput (LEFT and
RIGHT) to the MC462 (Power Amplifier 2) Bal- ment to the MC462 Power Amplifier:
Caution: Do not connect the AC Power Cord to the
MC462 Rear Panel until after the Loudspeaker anced INput (RIGHT and LEFT). Place the INPUT Bare wire cable ends:
Connections are made and the protective Termi- MODE Switch in the BALANCED Position. Carefully remove sufficient insulation from the
nal Connections Covers are installed. Failure to 5. Using a suitable tool remove the four screws from cable ends, refer to figures 2, 3 & 4. If the cable
observe this could result in Electric Shock. the MC462 Rear Panel and temporarily place them is stranded, carefully twist the strands together
The connection instructions below, together with the in a safe place. Refer to figure 1. as tightly as possible.
MC462 Connection Diagram located on the separate These McIntosh MC462 Stereo Power Amplifiers with
folded sheet “Mc1B”, is an example of a typical audio Quad Balanced Circuitry are designed for Loudspeak-
system. Your system may vary from this, however the ers with an impedance of 2 ohms, 4 ohms or 8 ohms.
actual components would be connected in a similar Connect a single Loudspeaker only to the Right and Figure 2 Figure 3 Figure 4
manner. For additional information refer to “Connec- Left Output Terminals. Notes: 1. If desired, the twisted ends can be tinned
tor and Cable Information” on page 3. with solder to keep the strands together.
9
 2. The prepared bare wire cable ends may be 10. Referring to figure H,
inserted into spade lug connectors for use connect the Loudspeaker Cover Openings Cover Openings
outside the United States and Canada only. hookup cables with ba-
3. Banana plugs are for use in the United nana plugs into the holeF Figure H
States and Canada only. Figure
at the top of the terminal
Banana Plugs are for use in the United States and to the MC462 Negative Output Terminal and Posi-
Canada only: tive Output Terminal indentified as 2Ω (ohms),
7. Locate the Terminal Connections Covers from the
DISABLED

4Ω (ohms) or 8Ω (ohms) connection to match the

inside of the MC462 shipping carton. Insert the impedance of the Loudspeaker, being careful to
just prepared Loudspeaker hookup cables thru the observe the correct polarities.
cover openings, one cover for each channel. Refer Note: The illustration in figure 5 is connections for Cover Screws Cover Screws
to figure 5. 8Ω (ohms) Loudspeakers. Figure 6 (Outside USA and Canada)
If the Loudspeaker’s impedance is in-between the 14. Connect the Loudspeaker hookup cables to the
Cover Openings Cover Openings available connections, use the nearest lower imped- MC462 Negative Output Terminal and Positive
ance connection. Refer to “General Information” Output Terminal indentified as 2Ω (ohms), 4Ω
Note 3 on page 2 for additional information. (ohms) or 8Ω (ohms) connection to match the
WARNING: Loudspeaker terminals are hazard- impedance of the Loudspeaker, being careful to
ous live and present a risk of electric observe the correct polarities. Insert the spade
DISABLED shock. For additional instruction on lug connector or prepared section of the cable end
making Loudspeaker Connections con- into the terminal side access hole, and tighten the
tact your McIntosh Dealer or McIn- terminal cap until the cable is firmly clamped into
tosh Technical Support.
the terminals so the lugs or wire cannot slip out.
Cover Screws Cover Screws 11. Attach the Terminal Connections Covers to the Refer to figures 7 and 8.
Figure 5 (Inside USA and Canada) MC462 Rear Panel with the previously removed
8. Attach the previously prepared bare wire cable Screws. Refer to figure 5.
ends into the banana plugs and secure the connec- 12. Connect the MC462 power cord to an active AC
tions. Refer to figure F. outlet.
9. Rotate the top of the Output Terminal
Post clockwise until it is finger tight. Spade Lug or Wire Connections: Figure 7 Figure 8
Refer to figure G. Then using the Mc- Figure F 13. Locate Figure
the Terminal
H Connection Covers from the
inside of the MC462 shipping carton. Insert the Note: The illustration in figure 6 is connections for
Intosh Wrench, rotate the top of the 8Ω (ohms) Loudspeakers.
Output Terminal one quarter of a turn just prepared Loudspeaker hookup cables thru the
cover openings, one cover for each channel. Refer If the Loudspeaker’s impedance is in-between
(90° ). Do not over tighten. Refer to the available connections, use the nearest lower
figure E. to figure 6.
impedance connection. Refer to “General Informa-
tion” Note 3 on page 2 for additional information.
Figure G

10
 Output Terminals and How to Connect for Bi-Amp

WARNING: Loudspeaker terminals are hazard-

ous live and present a risk of electric
shock. For additional instruction on
making Loudspeaker Connections con-
tact your McIntosh Dealer or McIn-
tosh Technical Support.
15. Attach the Terminal Connections Covers to the
MC462 Rear Panel with the previously removed
Screws. Refer to figure 6.
16. Connect the MC462 power cord to an active AC
outlet.

11
 Front Panel Displays and Controls

Meter indicates the Standby Power Meter indicates the

Left Channel Output On Indicator Right Channel Output
LED indicates when the Left LED indicates when the Right
of the amplifier of the amplifier
Channel Amplifier POWER Channel Amplifier POWER
GUARD circuit activates GUARD circuit activates

METER Switch selects POWER Switch Turns AC Power Off,

the display modes of the Remote, AC Power On
Power Output Meter and
Meter Illumination

12
 How to Operate

How to Operate
Power On Auto Off Switch
To have the MC462 automatically turn On or Off The MC462 incorporates Power Save Circuitry to
when a Preamplifier or A/V Control Center turns On automatically place the MC462 into the power saving
or Off, rotate the power switch to Standby Mode approximately 30 minutes after there
the Remote position. For manual has been an absence of an audio input signal.
operation, rotate the power switch When there is a Power Control Connection be-
to the On or Off position as desired. tween the MC462 and a Preamplifier with Power Save
Refer to figure 9. Circuitry, the AUTO OFF Switch is bypassed (located
Note: There must be a power con- on the Rear Panel of the MC462). Refer to figure 13.
trol connection between the Figure 9 Figure 11 In the event there is no
MC462 and the Audio Pre- Hold - The meter pointer is locked to the high- Power Control Connection
amplifier (or A/V Control Center), in order for the est power peak in a sequence of peaks. and the Power Save Circuitry
remote power turn-on to function. It is electronically held to this power is activating inappropriately DISABLED
level until a higher power peak passes relative to your specific use of Figure 13
Meter Selection through the amplifier. The meter point- the MC462, place the AUTO
Rotate the meter mode switch to select the meter op- er will then rise to the newer higher OFF Switch in the DISABLE position.
eration mode you desire. Refer to indication. If no further power peaks Note: If the Power Save Circuitry has switched Power
figures 10 and 11. are reached, the meter pointer will to the MC462 OFF, place the POWER in the OFF
Lights Off - Meter lights are very slowly return to its rest position Position and then in the ON position to reset the
turned off and the or lower power level. The decay rate is circuitry.
meter will contin- approximately 6dB per minute.
ue to indicate the Figure 10 Note: The MC462 Power Output Meter
power output. indicates the actual power delivered
Note: When Power Control Input of the to the loudspeakers by responding
MC462 is connected to an Audio to the combination of current and
Preamplifier or A/V Control Center voltage output.
with Remote Meter Illumination
Control, the Meter Illumination will Input Mode Switch
automatically be remotely con- The Input Mode Switch, which is located on the Rear
trolled (On/Off) with the METER Panel of the MC462, allows
Switch set to the WATTS or HOLD selection of either the Bal-
position.
anced or Unbalanced Input.
Watts- The meters respond to all the musi- Refer to figure 12.
cal information being produced by the DISABLED
amplifier. They indicate to an accuracy Figure 12
of at least 95% of the power output with
only a single cycle of a 2000Hz tone
burst.
13
Technical Description
McIntosh Laboratory, the company who introduced The MC462 has a continuous average power output design negative feedback circuits so they contribute
the world’s first amplifier that could be called “High rating of 450 watts and with a peak output current of to the extremely low distortion performance expected
Fidelity”, has done it again. The McIntosh engineering 75 amperes per channel; making this one of the most from a McIntosh amplifier. The typical McIntosh
staff has created a Power Amplifier without compro- advanced amplifiers available today. The distortion owner would never accept the approximately 100
mise, using the most advanced McIntosh circuit design limits for the MC462 are no more than 0.005% at times higher distortion of many non-feedback designs.
concepts. rated power output for all frequencies from 20Hz to Double Balanced Push-Pull design is used from
20,000Hz. Typical performance input to output. Each half of the amplifier contains
at mid frequencies is less than complimentary balanced circuitry. The resulting Quad
0.002%. The true distortion Balanced configuration cancels even order distortion.
readings on the MC462 are so Refer to figure 14.
low, it takes special measuring All transistors are selected to have nearly constant
techniques to make accurate current gain over the entire current range they must
readings. The MC462 can deliver cover. Output transistors in particular, have matched
the best possible performance uniform current gain, high current bandwidth prod-
from any type of high quality uct and large active region safe operating area. These
loudspeaker system. Refer to Power Transistors are the very latest in semiconductor
figure 13. technology and incorporate a new design known as
Creating an amplifier with ThermalTrak™. Refer to figure 15. This allows for the
this level of performance did not instantaneous and accurate monitoring of the Power
come easily. Many months of de- Transistor Temperature. The MC462
sign, testing and measuring were Power Output Circuitry has a specially
required. Extensive controlled designed bias circuit to take full advan-
listening tests, the ultimate form tage of the ThermalTrak™ Power Transis-
of measuring, were made before tors and thus precisely controls the power
the final design was accepted. amplifier operation over a wide range
of music conditions with the benefits of
Design Philosophy lower distortion and cooler operation.
The design philosophy incor- Precision metal film resistors and low Figure 15
porated in the MC462 involved dielectric absorption film capacitors are
several different techniques, all used in all critical circuit locations.
based on sound scientific logic. The output signals of the two balanced circuits
Every stage of voltage or cur- are coupled together in the unique McIntosh MC462
rent amplification must be as Output Autoformer. It provides low distortion power
linear as possible prior to the use transfer at frequencies from below 20Hz to well
Figure 13 of negative feedback. McIntosh beyond 20,000Hz with optimum impedance points of
engineers know how to properly two ohms, four ohms and eight ohms. The unequaled

14
 Technical Description

expertise of McIntosh in the design and than one loudspeak-

manufacturing of autoformers is legend- er connected in
ary in the high fidelity industry. parallel, the load to
The high efficiency circuit design of the power amplifier
the MC462 contributes to low operat- may drop to two
ing temperatures. More than 2800 ohms or even less.
square inches of heat sink area keep the A power amplifier
MC462 operating safely with convec- connected to a load
tion cooling. No fans are needed. Refer that is lower than
to figure 16. optimum, causes
more output cur-
Autoformers rent to flow, which
All solid state power amplifier output results in extra heat
circuits work best into what is called an being generated in
optimum load. This optimum load may the power output
Figure 16 vary considerably from what a loud- stage. This increase
speaker requires. In the case of more in temperature will
result in a reduced

Figure 17

life expectancy for the amplifier.

The special Balanced Winding
ThermalTrak
DC BIAS

UNBALANCED
INPUT
Autoformer creates an ideal match
UNBALANCED
OUTPUT

THERMAL
between the power amplifier output
+
stage and the loudspeaker. Refer to
SENSORS OUTPUT
AMP

INPUT MODE
SWITCH
POWER GUARD
ATTENUATOR
BALANCED
AMP
MUTE figure 17.
-
AMP There is absolutely no perfor-
BALANCED
+ mance limitation with an Autoform-
er. Its frequency response exceeds
INPUT
-

BALANCED
OUTPUT
+
ThermalTrak
DC BIAS
Block Diagram that of the output circuit itself, and
extends well beyond the audible
-
of the
Power Amplifier range. Its distortion level is so low it
(one channel shown) is virtually impossible to measure.
In the rare event of a power
Figure 14 amplifier output circuit failure, the

15
Technical Description, con’t
McIntosh Autoformer provides absolute protection Protection Circuits the harsh and damaging Without Power Guard
from possible damage to your valuable loudspeakers. The MC462 incorporates the McIntosh Sentry Moni- distortion due to clipping.
The unequaled expertise of McIntosh in the design tor Output Tran- The Power Guard
and manufacturing of Autoformers is legendary in the sistor Protection circuit is a waveform
high fidelity industry. McIntosh engineers know how Circuit. Refer to comparator, monitoring
to do it right. Figure 19. There is both the input and output
absolutely no com- waveforms. Under normal
Power Output Meter promise in sonic Normal Operating Area
operating conditions,
The McIntosh MC462 has large Output Watt Me- performance with there are no differences
ters that respond this circuit, and it between the shape of
Sentry Monitor Output
95% full scale to ensures safe opera- Safety Area Transistor these waveforms. If the
Failure
a single cycle tone tion of the ampli- amplifier is overdriven,
burst at 2kHz. fier under even Figure 19 there will be a difference
Figure 21
Refer to figure the most extreme between the two signal
18. Voltage and operating conditions. The different types of protection waveforms. When the With Power Guard
current outputs circuits incorporated in the MC462 insure a long and difference exceeds 0.3%,
are electronically safe operating life. This is just one of the many char- the Power Guard acti-
measured, multi- acteristics of McIntosh Power Amplifiers that make vates the PG light and
plied and fed to a them world famous. a dynamic electronic
special circuit that The MC462 also includes the unique patented attenuator at the ampli-
accelerates the McIntosh Power Guard circuit. Power Guard elimi- fier input reduces the
Figure 18
pointer movement nates the possibility of ever overdriving the amplifier input volume just enough
in the upward direction. Refer to figure 25 on the next into clipping. Refer to Input Test Signal to prevent any further in-
page. When the pointer reaches its peak it pauses only figures 20, 21 and 22. (14kHz & 15kHz) crease in distortion. The
long enough for the human eye to perceive its position, An overdriven amplifier Power Guard circuit acts
then drops. It is almost 10 times faster than a profes- can produce both audible so fast that there are ab- Figure 22
sional VU meter. and inaudible distortion solutely no audible side
A front panel switch is provided to change the levels exceeding 40%. effects and the sonic purity of the music reproduction
meter to the Watts Hold Mode of operation. This al- The audible distortion is is perfectly preserved. The MC462 Power Ampli-
lows fast upward movement of the pointer but greatly unpleasant to hear, but fier with Power Guard is not limited to just the rated
increases Hold Time at the peak of its travel. The the inaudible ultrasonic power output, but will actually produce distortion free
highest power output of the source material is thus distortion is also undesir- output well above its rated power due to the McIntosh
recorded. able, since it can damage philosophy of conservative design.
valuable loudspeaker
system tweeters. You Figure 20
will never experience

16
 Technical Description, con’t

Block Diagram POWER

CONTROL
of the
Power Supply The power amplifier draws high current from the AC
power line. Therefore, it is important that they plug
LIGHTING CONTROL
CONTROL LOGIC
BACKUP
POWER SUPPLY directly into the wall outlet.
Also, most owners desire one power switch for the
AC Power
INRUSH
CURRENT MAIN RELAYS
whole audio system. The MC462 is equipped with a
LIMITER
circuit that provides remote Power Control from a Mc-
Figure 23 Intosh A/V Control Center. Refer to figure 26. When
the A/V Control Center is switched On, a (+5V) signal
Power Supply Circuits
operates the power relay in the MC462. The MC462
To compliment the design of the MC462 Power Am-
also has two remote Power Control Out Jacks. The
plifier Circuitry, there is a high current high voltage
Power Control signal from these jacks is delayed by a
power supply. Refer to figures 23 and 26.
fraction of a second so that the turn on power surge of
The very large Power Transfomer can supply over 13
the next power amplifier occurs at a later time. This
amps of current. Refer to figure 24 (golf ball is for
helps prevent power circuit overload that could trip
size comparsion).
circuit breakers or blow fuses, a very important fea-
ture in high power Home Systems employing multiple
MC462 Power Amplifiers.

Figure 25

Figure 24
It is enclosed in the legendary McIntosh Potted Enclo-
sures and weighs 30 lbs. The six super size main filter
capacitors can store over 350 Joules of energy which
is necessary for the wide dynamic range that “Digital
Audio” demands. Refer to figure 25. Figure 26
17
 Specifications

Specifications
Power Output Intermodulation Distortion Power Requirements
Minimum sine wave continuous average power output 0.005% maximum, if the instantaneous peak power Field AC Voltage conversion of the MC462 is not
per channel, with both channels operating is: output does not exceed twice the rated power output possible. The MC462 is factory configured for one of
450 watts into 2 ohm load for any combination of frequencies from 20Hz to the following AC Voltages:
450 watts into 4 ohm load 20,000Hz. 100V ~ 50/60Hz at 12 Amps
450 watts into 8 ohm load 110V ~ 50/60Hz at 11 Amps
Wide Band Damping Factor 120V ~ 50/60Hz at 10 Amps
Output Load Impedance Greater than 40 127V ~ 50/60Hz at 10 Amps
2, 4 or 8 ohms 220V ~ 50/60Hz at 6 Amps
Input Impedance 230V ~ 50/60Hz at 6 Amps
Rated Power Band 22,000 ohms Balanced 240V ~ 50/60Hz at 6 Amps
20Hz to 20,000Hz 22,000 ohms Unbalanced Standby: less than 0.5 watt
Note: Refer to the rear panel of the MC462 for the cor-
Total Harmonic Distortion Voltage Gain rect voltage.
0.005% maximum harmonic distortion at any power 29dB, 8 Ohms
level from 250 milliwatts to rated power, 20Hz to 26dB, 4 Ohms Overall Dimensions
20,000Hz 23dB, 2 Ohms Width is 17-1/2 inches (44.5cm)
Height is 9-7/16 inches (24cm) including feet
Dynamic Headroom Power Guard Depth is 22-1/2 inches (57.2cm) including the Front
3.0dB Less than 2% Total Harmonic Distortion with up to a Panel, Handles and Cables
14dB overdrive signal
Frequency Response Weight
+0, -0.25dB from 20Hz to 20,000Hz Power Control Input 115 pounds (52.3 kg) net, 148 pounds (67.3 kg) in ship-
+0, -3.0dB from 10Hz to 100,000Hz 5-15VDC, less than 1mA ping carton

Input Sensitivity (for rated output) Power Control Output 1 and 2 Shipping Carton Dimensions
4.2 Volts Balanced 12VDC, 50mA maximum total Width is 29-1/2 inches (74.93cm)
2.1 Volts Unbalanced Output is delayed 0.2 seconds from turn On Depth is 29 inches (73.66cm)
Height is 17 inches (43.18cm)
Signal To Noise Ratio (A-Weighted)
95dB Balanced (122dB below rated output)
93dB Unbalanced (120dB below rated output)

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 - 20x2-1/4 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 Depart-
ment of McIntosh Laboratory. Refer to page 2. 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 034479 Shipping skid
4 401212 1/4 - 20x2-1/4 cap screw
4 104058 Flat washer

19
 McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, NY 13903
www.mcintoshlabs.com

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. 04187400