MA6900 Integrated Amplifier
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.
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 pressure levels. Continued exposure to high sound pressure levels can cause permanent hearing impairment or loss. User caution is advised and ear protection is recommended when playing at high volumes.
6. Caution: to prevent electrical shock do not use this
(polarized) plug with an extension cord, receptacle
or other outlet unless the blades can be fully inserted 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.
8. Only use attachments/accessories specified by the
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.
To prevent the risk of electric shock, do not remove cover or
back. No user serviceable parts inside.
9. The equipment shall be installed near the AC Socket
Outlet and the disconnect device shall be easily accessible.
10. Do not block any ventilation openings. Install in accordance 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 manufacturer, or sold with the equipment.
When a cart is used, use caution when
moving the cart/equipment combination
to avoid injury from tip-over.
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.
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.
18. Do not overload wall outlets, extension cords or integral 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.
Care 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. Servicing is required when the equipment 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 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 referred to qualified service personnel.
25. When replacement parts are required, be sure the service technician has used replacement parts specified by
McIntosh or have the same characteristics as the original part. Unauthorized substitutions may result in fire,
electric shock, or other hazards.
26. Upon completion of any service or repairs to this product, ask the service technician to perform safety checks
to determine that the product is in proper operating
Thank You
Your decision to own this McIntosh MA6900 Integrated
Amplifier ranks you at the very top among discriminating
music listeners. You now have “The Best.” The McIntosh
dedication to “Quality,” is assurance that you will receive
many years of musical enjoyment from this unit.
Please take a short time to read the information in this
manual. We want you to be as familiar as possible with all
the features and functions of your new McIntosh.
Please Take A Moment
The serial number, purchase date and McIntosh dealer
name are important to you for possible insurance claim or
future service. The spaces below have been provided for
you to record that information:
Serial Number:
Purchase Date:
Dealer Name:
Technical Assistance
If at any time you have questions about your McIntosh
product, contact your McIntosh dealer who is familiar with
your McIntosh equipment and any other brands that may
be part of your system. If you or your dealer wish additional help concerning a suspected problem, you can receive technical assistance for all McIntosh products at:
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, New York 13903
Phone: 607-723-1545
Fax: 607-723-3636
Customer Service
If it is determined that your McIntosh product is in need of
repair, you can return it to your dealer. You can also return
it to the McIntosh Laboratory Service Department. For assistance on factory repair return procedure, contact the
McIntosh Service Department at:
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, New York 13903
Phone: 607-723-3515
Fax: 607-723-1917
Copyright 2001 ã by McIntosh Laboratory, Inc.
Introduction and Performance Features
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 Loudspeakers ................................... 8
How to Connect for Audio and Data Control ................... 9
How to Connect for Video .............................................. 10
How to Connect for a Second Room .............................. 11
Front Panel Controls, Display, Indicator Push-Button
and Switch ...................................................................... 12
How to Operate ............................................................... 13
Remote Control Push-Buttons ........................................ 16
How to Operate by Remote Control ............................... 17
Technical Description ..................................................... 18
Specifications ................................................................. 22
Packing Instruction ......................................................... 23
Now you can take advantage of traditional McIntosh standards of excellence in the MA6900 Integrated Amplifier.
Two 200 watt high current output channels will drive any
high quality loudspeaker system to its ultimate performance and the flexible Preamplifier Selection provides for
hookup and control of various input sources. The MA6900
reproduction is sonically transparent and absolutely accurate. The McIntosh Sound is “The Sound of the Music Itself.”
General Notes
1. The following parts are available from the McIntosh Parts
Power Control Cable Part No. 170-202
Six foot, 2 conductor shielded, with two 1/8 inch stereo
mini phone plugs.
Jumper Plugs Part No. 117-781
RCA Phono Jumpers, 14mm center spacing.
2. For additional connection information, refer to the owner’s
manual(s) for any component(s) connected to the MA6900.
3. The MA6900 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 (76.2m) or less,
use at least 12 Gauge.
5. Pin configuration for the XLR Balanced Input connectors on
the MA6900: PIN 1: Shield or ground
PIN 2: + input
PIN 3: - input
6. In the event that the MA6900 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 MA6900 has returned to a safe operating
temperature, normal operation will resume.
Performance Features
Power Output
The MA6900 consists of two separate power amplifier
channels, each capable of 200 watts into 2, 4 or 8 ohm
speakers with less than 0.005% distortion.
Electronic Input Switching
Digital Logic integrated circuits drive Electromagnetic
Switches on all six inputs and operating functions for reliable, noiseless, distortion free switching.
· 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 MA6900 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 8 ohms. The Autoformers
also provide perfect DC protection for your valuable loudspeakers.
Illuminated Power Meters
The Illuminated Power Output Meters on the MA6900 are
peak responding, and indicate the power output of the amplifier.
MA6900 Dimensions
MA6900 Dimensions
The following dimensions can assist in determining the
best location for your MA6900. There is additional information on the next page pertaining to installing the
MA6900 into cabinets.
Front View of the MA6900
7 -1/8"
7 -5/8"
Rear View of the MA6900
Side View of the MA6900
0.48cm 15.88cm
The MA6900 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 MA6900 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 MA6900 is removed from the
custom installation and used free standing. The required
panel cutout, ventilation cutout and unit dimensions are
Always provide
adequate ventilation
for your MA6900.
Cool operation ensures the longest
possible operating
life for any elecMA6900 Front Panel
tronic instrument. Do Custom Cabinet Cutout
not install the
MA6900 directly
above a heat generating component such
as a high powered
amplifier. If all the
components are inCabinet
stalled in a single
cabinet, a quiet running ventilation fan
for Ventilation
can be a definite asset in maintaining all
the system components at the coolest
MA6900 Side View
possible operating
in Custom Cabinet
A custom cabinet
installation should
provide the followShelf
ing minimum spacing dimensions for
cool operation. Allow at least 6 inches
(15.24cm) above the
top, 2 inches
MA6900 Bottom View
(3.81cm) below the in Custom Cabinet
bottom and 1 inch
(2.54cm) on each side of the amplifier, so that airflow is
not obstructed. Allow 20 inches (50.8cm) depth behind the
front panel. Allow 1 inch (2.54cm) in front of the mounting
panel for knob clearance. Be sure to cut out a ventilation
hole in the mounting shelf according to the dimensions in
the drawing.
6 -5/8"
Cutout Opening for Custom Mounting
Cutout Opening for Ventilation
MA6900 Rear Panel Connections and Switch
Main Fuse holder,
refer to information
on the back panel
of your MA6900 to
determine the correct fuse size and
Connections for
2, 4 or 8 ohm
for a Keypad
or IR Sensor
MAIN Output sends
a turn-on signal to an
external McIntosh
Power Amplifier
when the MA6900 is
turned on
Connect the
MA6900 power
cord to a live AC
outlet. Refer to information on the
back panel to determine the correct
CD1 balanced INPUTS
accept high level program
source signals
Outputs send a turn-on signal
to an external McIntosh
Power Amplifier when the
MA6900 Front Panel Output
1 and/or 2 is On
signals to McIntosh
Compatible Components to allow control
with the remote control
ACC Output sends a
turn-on signal to a
McIntosh Source
Component or Power
Control unit when the
MA6900 is turned on
provide the Record
Out Signal
and 2 supply
the Preamplifier
Output to either
the internal or
external power
connect the Preamplifier OUTPUT 1
Jacks to the POWER
AMP IN Jacks and
are needed for normal operation
inputs accept signals from a separate external
VIDEO inputs
for audio signals
from a LV, VCR,
TV or an A/V
Connections for
2, 4 or 8 ohm
GND terminal
accepts a
ground wire
from a turntable
CD2 inputs accept signals
from the output
of a tuner and
CD player
TAPE input
accepts signals
from the output of a tape
AUX accepts high level program
source signals, PH accepts signals
from a Moving Magnet phono cartridge, and the small slide switch
selects which one of these two inputs is active when the front panel
PH/AUX Push-button is pressed
How to Connect Loudspeakers
How to Connect Loudspeakers
Caution: The supplied AC Power Cord should not be
connected to the Rear Panel of the MA6900
Amplifier until after the Loudspeaker Connections
have been made. Failure to observe this could
result in Electric Shock.
1. Prepare the Loudspeaker Hookup Cables that attach to
the 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
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.
4 ohm
Banana plug connection:
Insert the banana plug into the hole at the top of the
Note: Banana Plugs are for use in the United States and
Canada only.
2. Connect the loudspeaker hookup cables to the output
terminals that match the impedance of your loudspeakers, being careful to observe the correct polarities. Output impedance connections of 2 ohms, 4 ohms and 8
ohms are provided. If the impedance of your loudspeakers 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
McIntosh Dealer or McIntosh Technical
4 ohm
How to Connect Audio Components
How to Connect Audio Components
1. Connect an Audio Cable from the McIntosh CD Player
Audio Outputs to the MA6900 CD2 INPUTS.
2. Connect an Audio Cable from a McIntosh Tuner 1 Outputs to the MA6900 TUNER INPUTS.
3. Connect an Audio Cable from a Turntable to the
PH/AUX INPUTS and the Turntable Ground Connection to the GND grounding post.
4. Connect an Audio Cable from the MA6900 TAPE
OUTPUTS to the Record Inputs of a Tape Recorder
and from the MA6900 TAPE INPUTS to a Tape Recorder Outputs.
5. Connect a Control Cable from the MA6900 POWER
CONTROL ACC Jack to the Power Control In on the
McIntosh Tuner.
6. Connect a Control Cable from the McIntosh Tuner
Power Control Out Jack to the Power Control In jack
on the McIntosh CD Player.
7. Connect a Control Cable from the MA6900 TUNER
DATA PORT Jack to the McIntosh Tuner Data In
(Tuner 1).
8. Connect a Control Cable from the MA6900 CD2
DATA PORT Jack to the McIntosh CD Player Data In
9. Connect the MA6900 Power Cord to a live AC outlet.
McIntosh Tuner
McIntosh CD Player
To AC Outlet
Tape Recorder
How to Connect for Video Switching
How to Connect for Video Switching
1. Connect a Data cable from the MA6900 VIDEO DATA
PORT to the Audio/Video Selector Data In jack.
2. Connect the Audio/Video Selector Control Center Audio Outputs to the MA6900 VIDEO INPUTS.
3. Connect the Audio/Video Selector Video Monitor Output to a Monitor/TV.
Note: Either or both Audio/Video Selector Monitor
Output(s) may be connected to the Monitor/TV.
4. Connect a McIntosh DVD/CD Player Audio Outputs to
the Audio/Video Selector V-Aux Audio Inputs, the
Video Output to the Audio/Video Selector Video Input
and the Control Out to the Audio/Video Selector Data
Output jack.
5. Connect a Control Cable from the MA6900 POWER
CONTROL ACC Jack to the Power Control In on the
McIntosh DVD/CD Player.
6. Connect other video source components to the appropriate audio and video and data jacks on the Audio/
Video Selector.
Audio/Video Selector
McIntosh DVD Player
How to Connect for a Second Room
How to Connect for a Second Room
1. Connect Audio Cables from the MA6900 OUTPUTS 2
to the Second Power Amplifier Inputs.
2. Connect Hookup Cables from the Second Power Amplifier to the loudspeakers. Refer to page 8 in this
Owner’s Manual for connection details.
3. Connect a Control Cable from the MA6900 POWER
CONTROL 2 Jack to the Power Control In of a McIntosh Power Amplifier.
4. Connect an RG6 or RG59U coaxial cable from the
EXTernal SENSOR Jack to a Keypad.
Note: A Wall Mounted IR Sensor may also be used in place
of the keypad.
McIntosh Power Amplifier
4 ohm
4 ohm
Front Panel Controls, Push-Buttons and Switch
The BALANCE control
allows adjustment of
the relative volume balance between channels
Equalizer provides
12dB of boost or cut
at the center frequencies indicated above
each control
METER indicates the
Left Channel Power
Output of the amplifier
IR Sensor
from a remote control
Select any one
of the six Audio
signal sources
switch turns
all AC power
METER indicates the
Right Channel Power
Output of the amplifier
LEDs light when the
amplifier’s channel
circuit activates
allows connection of
Stereo Headphones for
private listening
MONO push-button
combines the left and
right channel signals for
Mono operation
and 2 pushbuttons turn the
Speakers and
Outputs On or
MUTE push-button
mutes the listening
VOLUME control
allows adjustment of
the listening level for
both channels
provides frequency response contoured to compensate for the
behavior of the
human ear at
softer listening
push-button turns
the MA6900 ON,
or OFF (Standby)
How to Operate
How to Operate
Power On
Press the POWER switch to ON. The Red LED above the
STANDBY/ON push-button, lights to
indicate the MA6900 is in Standby
mode. To turn On the MA6900, press
the STANDBY/ON push-button. The
MUTE LED will light for approximately two seconds after turn on. ReFigure 1
fer to figures 1 and 2.
Note: For normal
operation, turn the
MA6900 On and
Off with the
Standby/On pushbutton. If the
amplifier is not
going to be used for
an extended time,
turn off all AC
Power with the
Power Switch. You
may also turn On
the MA6900 by
simply pressing the
desired Source
Selection Pushbutton on the Front
Panel or Remote
PH/AUX Inputs
When using a phono player with a moving magnet cartridge connected to the PH/AUX inputs,
set the PH AUX switch to the PH position. When using an auxiliary program
source component connected to the PH/
AUX inputs, set the PH AUX switch to
the AUX position. Refer to figure 4.
Figure 4
Balance Control
Adjust the BALANCE control as needed to achieve approximately equal listening volume levels in each loudspeaker. Turn the BALANCE to the left to emphasize the
Left Channel by reducing the level of the Right Channel.
Turn the BALANCE to the right to emphasize the Right
Channel by reducing the level of the Left Channel.
Equalizer Controls
Each of the five Equalizer Frequency Controls will raise or
lower by approximately12dB, the amplitude of the band of
frequencies centered at the frequency marked above the
controls. Both Left and Right Channels are affected. Refer
to figure 5. At the center detent or flat position of the controls, all equalizer circuit components are removed from
the signal path.
Source Selection
Select the desired source
with the appropriate pushbutton switch on the Front
Panel or Remote Control.
Refer to figures 2 and 3
and page 16 for additional
Loud Switch
Press the LOUD push-button to add loudness bass compensation to the volume control for improved low level listening.
Volume Control
Adjust the VOLUME control for the desired listening level.
Press the MONO push-button to combine left and right stereo signals to mono at the SPEAKERS 1 and 2 and HEADPHONES output.
Figure 5
Figure 2
Figure 3
Press the MUTE push-button to mute audio in all outputs
except the HEADPHONES and TAPE OUTPUT. The
MUTE LED above the push-button will flash on and off to
indicate that Mute is active. To unmute audio, press
MUTE, press the Remote Control Volume push-button(s)
or press an Input push-button.
How to Operate, con’t
Outputs 1 and 2
Press OUTPUTS Push-button 1 to switch the Speakers On
or Off. The
also switch the
Figure 6
and 2 On or Off
for connection to external Power Amplifier(s). Press either
push-button individually, or both together. Refer to figure
Headphones Jack
Connect a pair of dynamic headphones to the Headphones
Jack for private listening. Press Mute to mute all other outputs including the amplifier connected to the loudspeakers.
Refer to figure 6.
Reset of Microprocessors
In the event that the controls of the MA6900 stop functioning, push the POWER switch OFF and wait about two minutes. Then push the POWER switch ON followed by pushing the STANDBY/ON push-button. This will reset the
MA6900 microprocessors and the Integrated Amplifier
should be functioning normally.
Note: The above condition is usually caused by either
interruptions in AC power and/or major changes that
may occur in AC power line voltage.
Using a Separate Power Amplifier
There are two different ways to use a separate power amplifier with a MA6900. The first way
is to use the separate amplifier instead
of the MA6900 built-in Power Amplifier. Connect the loudspeakers to the
separate power amplifier and remove
the McIntosh Jumpers that are located
Figure 7
between the OUTPUTS 1 Jacks and
the POWER AMP INput Jacks. Refer to figures 7 and 8.
Note: The McIntosh Jumpers must be connected, between the
above mentioned jacks, when the MA6900 Internal
Power Amplifier is to be used.
The second way is to use both a separate power amplifier and the MA6900
built-in Power Amplifier. Connect one
pair of loudspeakers to the separate
power amplifier and the second pair to
the MA6900.
No Jumpers
Figure 8
Note: The MA6900 VOLUME Control will affect the sound
level of all the loudspeakers.
How To Make A Tape Recording
1. Select the source signal you wish to record with the
appropriate Front Panel input push-button. If you wish
to record from an Audio/Video source connected to the
optional McIntosh Audio/Video Selector Audio/Video
Selector, using the Remote Control, select the desired
source connected to the McIntosh Audio/Video Selec-
Figure 9
tor. Refer to figure 9.
2. Adjust the record level using the tape recorder volume
control and proceed with the recording process.
3. To listen to the tape playback of the program source
just recorded, press the TAPE input push-button.
Note: The MA6900 TAPE OUTPUTS are not affected by the
VOLUME or BALANCE controls.
Power Output Meters
The MA6900 Power Output Meters indicate the power delivered to the loudspeakers. 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.
Remote Control Push-Buttons
Turns AC Power ON or OFF to
certain McIntosh Components
when connected via the Data Port
Press to Power the MA6900
Selects Functions for
McIntosh Home Controller and as a “shift” key
when used with the AM
or FM push-buttons to
select Output (Spkr) 1 or
Selects one of the twelve
High Level Audio/Video
Sources or Phono Input
Selects On Screen Functions for McIntosh DVD
Players and certain CD
Selects CD Player or
Tape Recorder Functions
and also performs various
functions on a variety of
McIntosh Components
Selects the Fast Forward
Mode on Disc Players
and Tuning Up the AM/
FM Dial
Press the push-button
to illuminate the keys
Press to REVIEW Tuner
Station Presets and selects certain functions on
McIntosh CD Players
Selects the REWind
Mode on Disc Players
and Tuning Down the
AM/FM Dial
Press MODE to switch
between Stereo or Mono
Use to select tuner
presets, disc tracks or
any numbered operation
Press TRIM to turn the
Loudness Control On or
Selects Switched Output
1, AM Tuner Operating
Functions and Disc Selection on certain McIntosh
CD Players
Selects Switched Output
2, FM Tuner Operating
Functions and Track Selection on certain McIntosh CD Players
Mutes the audio
Adjusts the volume
level up or down
Note: The Remote Control push-buttons that
are blackened out are for use with
other McIntosh Products.
How to Operate by Remote Control
How to Operate by Remote Control
The supplied remote control is capable of directly controlling the functions of contemporary McIntosh Source Components connected to the MA6900. Earlier McIntosh
source components and other brand source components can
be controlled by the MA6900 with the addition of a McIntosh Remote Control Translator (RCT).
Note: Your McIntosh Dealer can assist you with the
installation and operation of the Remote Control
Translator (RCT).
Press the MUTE push-button to mute audio at the Preamplifier OUTPUTS 1, 2 and Speaker L, R OUTPUTs. The
TAPE OUTPUTS and HEADPHONES output are not affected by the MUTE function. The MUTE LED above the
push-button will flash on and off to indicate that Mute is
active. Press MUTE a second time to unmute audio.
Tuner Push-buttons
Press the AM or FM push-button to select the desired
broadcast band. Press and release the Channel Upp or
Downqpush-button to move from station to station. Press
and hold a Channel Upp or Downq push-button to move
continuously from station to station. Press REVIEW to
start the automatic brief audition of each of the presets
stored in the tuner memory. Press REVIEW a second time
to stop on a station preset and exit the Review process.
Press the Up or Down VOLUME push-button to raise or
lower the listening volume level.
Note: The TAPE OUPUTS are not affected by volume
Press the MONO push-button to combine left and right stereo signals to mono at the Preamplifier OUTPUTS 1, 2 and
Speaker L, R OUTPUTs.
Amplifier Selection
Press HOME push-button followed by the SPEAKER 1 or
2 push-buttons either separately or together, to control the
rear panel OUTPUTS 1, 2 which can feed signals to a
power amplifier or other accessory component.
Press the TRIM push-button to active the Loudness Compensations circuit.
Acc On
Press ACC ON to turn the power ON to a McIntosh Disc
Input Source Selection
Press any of the twelve input push-buttons to select a program source. When one of the Audio/Video Inputs (SAT,
LV, TV, VCR, VCR2 and DVD) are selected by remote
control, the MA6900 will automatically switch to the
VIDEO Input. If the Front Panel VIDEO Push-button is
pressed, the source device connected to the VIDEO INPUT
Jacks will be heard. When the optional McIntosh MVS Audio/Video Selector is added, multiple Audio/Video Inputs
Sources, such as LV, TV, VCR, VCR2 and DVD (V-Aux),
will become available by just pressing the desired program
source push-button on the remote control.
Acc Off
Press ACC OFF to turn the power OFF to a McIntosh Disc
CD/Tape Functions
Use these push-buttons to operate a CD player, CD changer
or tape recorder.
Note: While the LIGHTING push-button is being depressed,
the remote control will be unable to send a remote
command. When the LIGHTING push-button is released
the push-buttons will continue to stay illuminated for
approximately three seconds thus allowing you to send
the desired command. If any of the translucent pushbuttons are depressed, they will continue to stay
illuminated for approximately three seconds.
Numbered Push-buttons
Press push-buttons 0 through 9 to access tuner station presets or CD tracks/discs.
Press E to perform various functions on a variety of McIntosh Components. It will also pause the playing of a disc or
tape player.
Press and release the LIGHTING push-button to momentarily illuminate the upper half of the remote control pushbuttons.
Disc and Track
Use the DISC and TRACK push-buttons when a CD player
or changer is being used.
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 created 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 the most advanced Integrated Amplifier McIntosh has ever manufactured. The distortion limits
for the MA6900 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 MA6900 are so low, it takes
special measuring techniques to make accurate readings.
The MA6900 can deliver the best possible performance
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 measuring were required. Extensive controlled listening tests,
the ultimate form of measuring, were made before the final
design was accepted.
Bottom Inside View of the MA6900
Preamplifier Design Philosophy
All signal switching in the MA6900 is done by ElectroMagnetic devices. Electro-Magnetic Switching is a proven
The switch and coil connectors extend from the bottom in
technology that uses the latest in materials and manufactur- the form of printed circuit board terminals. When a DC
ing methods. Each switch consists of a glass tube that is
voltage is applied to the coil, current flows and creates a
filled with an inert oxygenfree atmosphere and sealed
Equalizer Control Adjustment Range
with tiny leads protruding
from either end. These leads
extend into the tube and
overlap one another with a
separation of a few thousandths of an inch. The leads
are made from a ferrous material that is influenced by a
magnetic field. They are first
plated with gold as a base
material, then with rhodium
and finally ruthenium. Ruthenium is the best contact
material known.
The glass assembly is
then placed in the center of a
multilayer coil of copper
wire. The entire assembly is
molded together in a tough
shock absorbing material.
Figure 10
Hz (Hertz)
Technical Description
magnetic field. The force of the field causes the leads to
bend and contact one another inside the sealed glass tube.
The inert gas eliminates corrosion of the contacts and insures a low resistance, distortion free switch.
All inputs, outputs, and data ports are controlled by
logic circuits in the MA6900. The logic is changed by front
panel push-buttons or by a microprocessor IR decoder.
This microprocessor IR decoder is programmed with exclusive McIntosh software. It receives data from the front
panel or external sensors and provides the command signals for input switching, data switching, and volume control.
The equalizer section uses several high technology operational amplifiers. The amplifier stage has been optimized for the best transient performance and minimum distortion. Five other operational amplifiers are arranged in a
circuit configuration that is the equivalent of a series turned
circuit. A control potentiometer inserts this series tuned circuit into either the feedback or input section of the equalizer amplifier. This provides a 12dB boost or cut at the frequency of the tuned circuit. Refer to figure 10. The overall
gain of the stage is 0dB when the potentiometer is at its
center detent position. In this position the tone control elements are completely removed from the signal path.
Power Amplifier Design Philosophy
The design philosophy incorporated in the MA6900 involved several different techniques, all based on sound scientific logic. Refer to figure 11. Every stage of voltage or
current amplification must be as linear as possible prior to
the use of negative feedback. McIntosh engineers know
how to properly design negative feedback circuits so they
contribute to the extremely low distortion performance expected from a McIntosh amplifier. The typical McIntosh
owner would never accept the approximately 100 times
higher distortion of many non-feedback designs.
All transistors are selected to have nearly constant current gain over the entire current range they must cover.
Output transistors in particular, have matched uniform current gain, high current-bandwidth product and large active
region safe operating area. An automatic tracking bias system completely eliminates any trace of crossover distortion. Precision metal film resistors and low dielectric absorption film capacitors are used in all critical circuit locations.
The output signal of the circuit is coupled together in
the unique McIntosh MA6900 Output Autoformer. It provides low distortion power transfer at frequencies from below 20Hz to well beyond 20,000Hz with optimum imped-
Block Diagram of the Amplifer and Meter Circuitry
Figure 11
The Autoformer creates an ideal match between the
power amplifier output stage and the loudspeaker. Refer to
figure 12. There is absolutely no performance limitation
with an Autoformer. Its frequency response exceeds that of
the output circuit itself, and extends well beyond the audible range. Its distortion level is so low it is virtually impossible to measure. In the rare event of a power amplifier
output circuit failure, the McIntosh Autoformer provides
absolute protection from possible damage to your valuable
Top Inside View of the MA6900
ance points of two ohms, four ohms and eight ohms. The
unequaled expertise of McIntosh in the design and manufacturing of autoformers is legendary in the high fidelity
The high efficiency circuit design of the MA6900 contributes to low operating temperatures. More than 621
square inches of heat sink area keep the MA6900 operating
safely with convection cooling. No fans are needed.
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 parallel, 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
Figure 12
for the amplifier.
Protection Circuits
The MA6900 incorporates it’s version of the McIntosh
Sentry Monitor output transistor
protection circuit. Refer to figure
13. 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 condiFigure 13
tions. The different types of protection circuits incorporated in the
MA6900 insure a long and safe operating life.
The MA6900 also includes the unique patented McIntosh Power Guard circuit.
Input Test Signal
Power Guard eliminates the
possibility of ever overdriving
the amplifier into clipping. Refer to figures 14, 15 and 16. An
overdriven amplifier can produce both audible and inaudible
distortion levels exceeding
40%. The audible distortion is
unpleasant to hear, but the inaudible ultrasonic distortion is
Figure 14
also undesirable, since it can
damage valuable loudspeaker
Without Power Guard
system tweeters. 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 amFigure 15
plifier channel is overdriven,
there will be a difference between the two signal waveforms. When the difference exceeds 0.3% (equivalent to
0.3% harmonic distortion), the Power Guard activates the
With Power Guard
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 audible side effects and the sonic
purity of the music reproduction
is perfectly preserved. The
MA6900 Amplifier with Power
Figure 16
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 Circuits
To compliment the design of the MA6900, there is a high
voltage power supply for both channels. Refer to figure 17.
The power amplifiers draw high current from the AC
power line. Therefore, it is important that they plug directly
into the wall outlet. Turn on inrush current is cushioned by
thermistors in the power transformer’s primary circuit.
This soft start eliminates component stress during turn-on.
The MA6900 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 MA6900 has the output current reserve to drive them. The MA6900 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.
Block Diagram of the Power Supply
Figure 17
Power Output
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 8 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 8 ohm loads
Dynamic Headroom
Frequency Response
+0, -0.5dB from 20Hz to 20,000Hz
+0, -3dB from 10Hz to 100,000Hz
Phono, 2.5mV for 2.5V rated output (0.5mV IHF)
High Level, 250mV for 2.5V rated output (50mV IHF)
Power Amplifier Input, 2.5V for rated output
Signal To Noise Ratio (A Weighted)
90dB (84dB IHF) below 10mV input, Phono Input
100dB (90dB IHF) below rated output, High Level
110dB below rated output, Power Amplifier
Intermodulation Distortion
Maximum Intermodulation Distortion if instantaneous peak output per channel does not exceed
twice the rated output, for any combination of frequencies from 20Hz to 20,000Hz, with all channels
operating is:
0.005% for 2, 4 or 8 ohm loads
Input Impedance
Phono, 47K ohms, 65pF
High Level, 22K ohms
Maximum Input Signal
Phono, 90mV
High Level, 8V
Preamplifier Maximum Voltage Output
Phono, 8V at tape output
High Level, 8V at tape output
Main Out, 8V at preamp output
Voltage Gain
High Level to Tape: 0dB
High Level to Main: 20dB
Wide Band Damping Factor
Greater than 40
Power Requirements
100 Volts, 50/60Hz at 4.8 amps
110 Volts, 50/60Hz at 4.4 amps
120 Volts, 50/60Hz at 4.0 amps
220 Volts, 50/60Hz at 2.0 amps
230 Volts, 50/60Hz at 2.0 amps
240 Volts, 50/60Hz at 2.0 amps
Note: Refer to the rear panel of the MA6900 for the correct
Overall Dimensions
Front Panel: 17-1/2 inches (44.45cm) wide, 7-1/8 inches
(18.10cm) high. Depth behind front mounting panel is 161/2 inches (41.91cm). Clearance required in front of the
Front Panel is 1 inch (2.54cm) for knobs.
74.5 pounds (33.8 Kg) net, 92.5 pounds (41.7 Kg) in shipping carton
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. Three #10 x 2-1/4
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 Department of McIntosh Laboratory. Please see the Part List for the correct part numbers.
Part Number
Shipping carton only
End cap (Foam pad)
Inside carton only
Top Pad
Bottom pad
Plastic foot (spacer)
Wood skid
#10 x 2-1/4 inch Wood screw
#10 x 1-3/4 inch Flat washer
Plastic foot
#10-32 x 3/4 inch Machine
#10 x 7/16 inch Flat washer
Sipping Carton Complete
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, NY 13903
McIntosh Part No. 040772