MA6900Owner’s Manual

McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 FAX: 607-724-0549

Integrated Amplifier

2

IMPORTANT SAFETYINSTRUCTIONS!

PLEASE READ THEM BEFOREOPERATING THIS EQUIPMENT.

WARNING - TO REDUCE RISK OFFIRE OR ELECTRICAL SHOCK, DONOT EXPOSE THIS EQUIPMENT TO

RAIN OR MOISTURE.

The lightning flash with arrowhead,within an equilateral triangle, is intendedto alert the user to the presence ofuninsulated “dangerous voltage” withinthe product’s enclosure that may be ofsufficient magnitude to constitute a riskof electric shock to persons.

NO USER-SERVICEABLE PARTSINSIDE. REFER SERVICING TO

QUALIFIED PERSONNEL.To prevent the risk of electric shock, do not remove cover or

back. No user serviceable parts inside.

The exclamation point within an equi-lateral triangle is intended to alert theuser to the presence of importantoperating and maintenance (servic-ing) instructions in the literature ac-companying the appliance.

1. Read these instructions.2. Keep these instructions.3. Heed all warnings.4. Follow all instructions.5. Do not use this apparatus near water.6. Clean only with a dry cloth.7. Do not block any ventilation openings. Install in

accordance with the manufacturer’s instructions.8. Do not install near any heat sources such as

radiators, heat registers, stoves, or otherapparatus (including amplifiers) that produceheat.

9. Do not defeat the safety purpose of the polarizedor grounding-type plug. A polarized plug has twoblades with one wider than the other. A groundingtype plug has two blades and a third groundingprong. The wide blade or the third prong areprovided for your safety. If the provided plugdoes not fit into your outlet, consult an electricianfor replacement of the obsolete outlet.

10. Protect the power cord from being walked on orpinched particularly at plugs, conveniencereceptacles, and the point where they exit from

the apparatus.11. Only use attachments/accessories specified by the

manufacturer.12. Use only with the cart, stand, tripod,

bracket, or table specified by themanufacturer, or sold with theapparatus. When a cart is used, usecaution when moving the cart/apparatus combination to avoid injury from tip-over.

13. Unplug this apparatus during lightning storms orwhen unused for long periods of time.

14. Refer all servicing to qualified service personnel.Servicing is required when the apparatus hasbeen damaged in any way, such as power-supplycord or plug is damaged, liquid has been spilledor objects have fallen into the apparatus, theapparatus has been exposed to rain or moisture,does not operate normally, or has been dropped.

15. Do not expose this equipment to dripping orsplashing and ensure that no objects filled withliquids, such as vases, are placed on theequipment.

16. To completely disconnect this equipment fromthe a.c. mains, disconnect the power supply cordplug from the a.c. receptacle.

17. The mains plug of the power supply cord shallremain readily operable.

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Customer Service

Technical Assistance

Please Take A Moment

Thank You

Copyright 2004 © by McIntosh Laboratory, Inc.

The serial number, purchase date and McIntosh dealername are important to you for possible insurance claim orfuture service. The spaces below have been provided foryou to record that information:

Your decision to own this McIntosh MA6900 IntegratedAmplifier ranks you at the very top among discriminatingmusic listeners. You now have “The Best.” The McIntoshdedication to “Quality,” is assurance that you will receivemany years of musical enjoyment from this unit.

Please take a short time to read the information in thismanual. We want you to be as familiar as possible with allthe features and functions of your new McIntosh.

Serial Number:Purchase Date:Dealer Name:

If it is determined that your McIntosh product is in need ofrepair, you can return it to your dealer. You can also returnit to the McIntosh Laboratory Service Department. For as-sistance on factory repair return procedure, contact theMcIntosh Service Department at:

McIntosh Laboratory, Inc.2 Chambers StreetBinghamton, New York 13903Phone: 607-723-3515Fax: 607-723-1917

If at any time you have questions about your McIntoshproduct, contact your McIntosh dealer who is familiar withyour McIntosh equipment and any other brands that maybe 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 StreetBinghamton, New York 13903Phone: 607-723-1545Fax: 607-723-3636

Table of ContentsSafety Instructions ............................................................ 2Thank You and Please Take a Moment ............................. 3Technical Assistance and Customer Service .................... 3Table of Contents .............................................................. 3Important Information ...................................................... 4Connector Information ..................................................... 4Introduction ...................................................................... 4Performance Features ....................................................... 4Dimensions ....................................................................... 5Installation ........................................................................ 6Rear Panel Connections and Switch ................................. 7How to Connect for Loudspeakers ................................... 8How to Connect for Audio and Data Control ................... 9How to Connect for Video .............................................. 10How to Connect for a Second Room .............................. 11Front Panel Controls, Display, Indicator Push-Buttonand Switch ...................................................................... 12How to Operate ............................................................... 13Remote Control Push-Buttons ........................................ 16How to Operate by Remote Control ............................... 17Technical Description ..................................................... 18Specifications ................................................................. 22Packing Instruction ......................................................... 23

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Performance Features

Introduction and Performance Features

Introduction

••••• Power OutputThe MA6900 consists of two separate power amplifierchannels, each capable of 200 watts into 2, 4 or 8 ohmspeakers with less than 0.005% distortion.

••••• Electronic Input SwitchingDigital Logic integrated circuits drive ElectromagneticSwitches on all six inputs and operating functions for reli-able, noiseless, distortion free switching.

••••• Power GuardBoth channels include the patented McIntosh Power Guardcircuit that prevents the amplifier from being overdriveninto clipping, with its harsh distorted sound that can alsodamage your valuable loudspeakers.

••••• Sentry Monitor and Thermal ProtectionMcIntosh Sentry Monitor power output stage protectioncircuits ensure the MA6900 will have a long and troublefree operating life. Built-in Thermal Protection Circuitsguard against overheating.

••••• Patented AutoformersMcIntosh designed and manufactured Output Autoformersprovide an ideal match between the amplifier output stagesand speaker loads of 2, 4 and 8 ohms. The Autoformersalso provide perfect DC protection for your valuable loud-speakers.

••••• Illuminated Power MetersThe Illuminated Power Output Meters on the MA6900 arepeak responding, and indicate the power output of the am-plifier.

Now you can take advantage of traditional McIntosh stan-dards of excellence in the MA6900 Integrated Amplifier.Two 200 watt high current output channels will drive anyhigh quality loudspeaker system to its ultimate perfor-mance and the flexible Preamplifier Selection provides forhookup and control of various input sources. The MA6900reproduction is sonically transparent and absolutely accu-rate. The McIntosh Sound is “The Sound of the Music It-self.”

Important Information1. The following parts are available from the McIntosh Parts

Department:Power Control Cable Part No. 170-202Six foot, 2 conductor shielded, with two 1/8 inch stereomini phone plugs.Jumper Plugs Part No. 117-781RCA Phono Jumpers, 14mm center spacing.

2. For additional connection information, refer to the owner’smanual(s) for any component(s) connected to the MA6900.

3. The MA6900 mutes the speaker outputs for approximately twoseconds when first turned on.

4. It is very important that loudspeaker cables of adequate sizebe used, so that there will be no power loss. The size isspecified 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. In the event that the MA6900 over heats, due to improperventilation and/or high ambient temperature, the protectioncircuits will activate. The Front Panel Power Guard LEDswill continuously indicate ON and the audio will be muted.When the MA6900 has returned to a safe operatingtemperature, normal operation will resume.

XLR ConnectorsBelow is the Pin configuration for the XLR Balanced InputConnectors on the MA6900. Refer to the diagram for con-nection:

PIN 1: Shield/GroundPIN 2: + InputPIN 3: - Input

Power Control and Trigger ConnectorsThe MA6900’s Power Control Outputs provide a 5 voltsignal. Use a 1/8 inch stereo miniphone plug to connect to thePower Control Input on otherMcIntosh Components.

Data Port ConnectorThe MA6900’s Data Port Output provides Remote ControlSignals. Use a 1/8 inch stereomini phone plug to connect to theData Port Inputs on McIntoshSource Units.

Connector Information

Positive

N/C

Ground

Data Signal

N/C

Ground

Pin 1Pin 2

Pin 3

5

MA6900 Dimensions

The following dimensions can assist in determining thebest location for your MA6900. There is additional infor-mation on the next page pertaining to installing theMA6900 into cabinets.

MA6900 Dimensions

17-1/2"44.45cm

7 -5/8"19.37cm

3/16"0.48cm

16-1/16" 40.8cm

Front View of the MA6900

Rear View of the MA6900

Side View of the MA6900

7 -1/8"18.10cm

13/16"2.06cm

6"15.24cm

12-3/16" 30.96cm

18-3/4"47.63cm

16-1/2" 41.91cm

6-1/4"15.88cm

1"2.54cm

13"33.02cm

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Installation

The MA6900 can be placed upright on a table or shelf,standing on its four feet. It also can be custom installed in apiece of furniture or cabinet of your choice. The four feetmay be removed from the bottom of the MA6900 when itis custom installed as outlined below. The four feet to-gether with the mounting screws should be retained forpossible future use if the MA6900 is removed from thecustom installation and used free standing. The requiredpanel cutout, ventilation cutout and unit dimensions areshown.

Always provideadequate ventilationfor your MA6900.Cool operation en-sures the longestpossible operatinglife for any elec-tronic instrument. Donot install theMA6900 directlyabove a heat generat-ing component suchas a high poweredamplifier. If all thecomponents are in-stalled in a singlecabinet, a quiet run-ning ventilation fancan be a definite as-set in maintaining allthe system compo-nents at the coolestpossible operatingtemperature.

A custom cabinetinstallation shouldprovide the follow-ing minimum spac-ing dimensions forcool operation. Al-low at least 6 inches(15.24cm) above thetop, 2 inches(3.81cm) below thebottom and 1 inch

Installation

6 -5/8"16.83cm

17-1/16"43.34cm

Cutout Opening for Custom Mounting

MA6900 Front Panel Custom Cabinet Cutout

CutoutOpening

forVentilation

Cutout Opening for VentilationSupportShelf

CabinetFrontPanel

ChassisSpacers

MA6900 Side Viewin Custom Cabinet

MA6900 Bottom Viewin Custom Cabinet

14-1/2" 36.83cm

1" 2.54cm

6"15.24cm

Openingfor Ventilation

10-3/8" 26.35cm

13" 33.02cm

13" 33.02cm

14-1/8" 35.88cm

2" 5.08cm

(2.54cm) on each side of the amplifier, so that airflow isnot obstructed. Allow 20 inches (50.8cm) depth behind thefront panel. Allow 1 inch (2.54cm) in front of the mountingpanel for knob clearance. Be sure to cut out a ventilationhole in the mounting shelf according to the dimensions inthe drawing.

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MA6900 Rear Panel Connections and Switch

Main Fuse holder,refer to informationon the back panelof your MA6900 todetermine the cor-rect fuse size andrating

Right OUTPUTConnections for2, 4 or 8 ohmloudspeakers

Left OUTPUTConnections for2, 4 or 8 ohmloudspeakers

The EXT(external)SENSOR(s)for a Keypador IR Sensor

TAPE inputaccepts signalsfrom the out-put of a tapedeck

GND terminalaccepts aground wirefrom a turn-table

VIDEO inputsfor audio signalsfrom a LV, VCR,TV or an A/VSelector

POWER CONTROLMAIN Output sendsa turn-on signal to anexternal McIntoshPower Amplifierwhen the MA6900 isturned on

POWER CONTROL 1 and 2Outputs send a turn-on signalto an external McIntoshPower Amplifier when theMA6900 Front Panel Output1 and/or 2 is On

POWER CONTROLACC Output sends aturn-on signal to aMcIntosh SourceComponent or PowerControl unit when theMA6900 is turned on

DATA PORTS sendsignals to McIntoshCompatible Compo-nents to allow controlwith the remote con-trol

Connect theMA6900 powercord to a live ACoutlet. Refer to in-formation on theback panel to deter-mine the correctvoltage

CD1 balanced INPUTSaccept high level programsource signals

OUTPUTS 1and 2 supplythe PreamplifierOutput to eitherthe internal orexternal poweramplifier

POWER AMP INinputs accept sig-nals from a sepa-rate externalpreamplifier

JUMPER PLUGSconnect the Pream-plifier OUTPUT 1Jacks to the POWERAMP IN Jacks andare needed for nor-mal operation

TAPE OUTPUTSprovide the RecordOut Signal

AUX accepts high level programsource signals, PH accepts signalsfrom a Moving Magnet phono car-tridge, and the small slide switchselects which one of these two in-puts is active when the front panelPH/AUX Push-button is pressed

TUNER andCD2 inputs ac-cept signalsfrom the outputof a tuner andCD player

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How to Connect Loudspeakers

Caution: The supplied AC Power Cord should not beconnected to the Rear Panel of the MA6900Amplifier until after the Loudspeaker Connectionshave been made. Failure to observe this couldresult in Electric Shock.

1. Prepare the Loudspeaker Hookup Cables that attach tothe Amplifier by choosing one of the methods below:

Bare wire cable ends:Carefully remove sufficient insulation from the cableends, refer to figures 1, 2 & 3. If the cable is stranded,carefully twistthe strands to-gether as tightlyas possible.

Note: If desired,the twistedends can be tinned with solder to keep the strandstogether, or attach spade lug and/or bananaconnector.

Spade lug or prepared wire connection:Insert the spade lug connector or prepared section ofthe cable end into the terminal side access hole, andtighten the terminal cap until the cable is firmlyclamped 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 theterminal.

Note: Banana Plugs are for use in the United States andCanada only.

2. Connect the loudspeaker hookup cables to the outputterminals 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 8ohms are provided. If the impedance of your loud-speakers is in-between the available connections, usethe nearest lower impedance connection.

WARNING: Loudspeaker terminals are hazardous liveand present a risk of electric shock. Foradditional instruction on makingLoudspeaker Connections contact yourMcIntosh Dealer or McIntosh TechnicalSupport.

RightLoudspeaker4 ohm

LeftLoudspeaker4 ohm

How to Connect Loudspeakers

9

How to Connect Audio Components

1. Connect an Audio Cable from the McIntosh CD PlayerAudio Outputs to the MA6900 CD2 INPUTS.

2. Connect an Audio Cable from a McIntosh Tuner 1 Out-puts to the MA6900 TUNER INPUTS.

3. Connect an Audio Cable from a Turntable to the PH/AUX INPUTS and the Turntable Ground Connec-

tion to the GND grounding post.4. Connect an Audio Cable from the MA6900 TAPE

OUTPUTS to the Record Inputs of a Tape Recorderand from the MA6900 TAPE INPUTS to a Tape Re-corder Outputs.

5. Connect a Control Cable from the MA6900 POWERCONTROL ACC Jack to the Power Control In on theMcIntosh Tuner.

6. Connect a Control Cable from the McIntosh TunerPower Control Out Jack to the Power Control In jackon the McIntosh CD Player.

7. Connect a Control Cable from the MA6900 TUNERDATA PORT Jack to the McIntosh Tuner Data In(Tuner 1).

8. Connect a Control Cable from the MA6900 CD2DATA PORT Jack to the McIntosh CD Player Data InJack.

9. Connect the MA6900 Power Cord to a live AC outlet.

To AC OutletTape Recorder Turntable

McIntosh CD PlayerMcIntosh Tuner

How to Connect Audio Components

OutIn

10

How to Connect for Video Switching

How to Connect for Video Switching

1. Connect a Data cable from the MA6900 VIDEO DATAPORT to the Audio/Video Selector Data In jack.

2. Connect the Audio/Video Selector Control Center Au-dio Outputs to the MA6900 VIDEO INPUTS.

3. Connect the Audio/Video Selector Video Monitor Out-put 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 Inputand the Control Out to the Audio/Video Selector DataOutput jack.

5. Connect a Control Cable from the MA6900 POWERCONTROL ACC Jack to the Power Control In on theMcIntosh DVD/CD Player.

6. Connect other video source components to the appro-priate audio and video and data jacks on the Audio/Video Selector.

McIntosh DVD Player

Audio/Video Selector

Monitor/TV

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How to Connect for a Second Room

How to Connect for a Second Room1. Connect Audio Cables from the MA6900 OUTPUTS 2

to the Second Power Amplifier Inputs.2. Connect Hookup Cables from the Second Power Am-

plifier to the loudspeakers. Refer to page 8 in thisOwner’s Manual for connection details.

3. Connect a Control Cable from the MA6900 POWERCONTROL 2 Jack to the Power Control In of a McIn-tosh Power Amplifier.

4. Connect an RG6 or RG59U coaxial cable from theEXTernal SENSOR Jack to a Keypad.Note: A Wall Mounted IR Sensor may also be used in place

of the keypad.

RightLoudspeaker4 ohm

LeftLoudspeaker4 ohm

McIntosh Power Amplifier

Keypad

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Front Panel Controls, Push-Buttons and Switch

POWERswitch turnsall AC powercompletelyON or OFF

MONO push-buttoncombines the left andright channel signals forMono operation

VOLUME controlallows adjustment ofthe listening level forboth channels

The BALANCE controlallows adjustment ofthe relative volume bal-ance between channels

MUTE push-buttonmutes the listeningaudio

STANDBY/ONpush-button turnsthe MA6900 ON,or OFF (Standby)

IR Sensorreceivescommandsfrom a re-mote con-trol

HEADPHONES jackallows connection ofStereo Headphones forprivate listening

METER indicates theLeft Channel PowerOutput of the amplifier

POWER GUARDLEDs light when theamplifier’s channelPOWER GUARDcircuit activates

METER indicates theRight Channel PowerOutput of the amplifier

LOUDNESSprovides fre-quency re-sponse con-toured to com-pensate for thebehavior of thehuman ear atsofter listeninglevels

OUTPUTS 1and 2 push-buttons turn theSpeakers andPreamplifierOutputs On orOff

Select any oneof the six Audiosignal sources

Equalizer provides12dB of boost or cutat the center frequen-cies indicated aboveeach control

13

How to Operate

How to Operate

Power OnPress the POWER switch to ON. The Red LED above theSTANDBY/ON push-button, lights toindicate the MA6900 is in Standbymode. To turn On the MA6900, pressthe STANDBY/ON push-button. TheMUTE LED will light for approxi-mately two seconds after turn on. Re-fer to figures 1 and 2.

Notes: For normal operation,turn the MA6900 Onand Off with theStandby/On push-button. If the amplifieris not going to be usedfor an extended time,turn off all AC Powerwith the PowerSwitch. You may alsoturn On the MA6900by simply pressing thedesired SourceSelection Push-buttonon the Front Panel orRemote Control. Foran explanation of theRemote Control Push-button functions, referto pages 16 and 17.

Source SelectionSelect the desired sourcewith the appropriate push-button switch on the FrontPanel or Remote Control.Refer to figures 2 and 3 andpage 16 for additional infor-mation.

Volume ControlAdjust the VOLUME controlfor the desired listening level.

PH/AUX InputsWhen using a phono player with a moving magnet cartridgeconnected to the PH/AUX inputs, setthe PH AUX switch to the PH position.When using an auxiliary program sourcecomponent connected to the PH/AUXinputs, set the PH AUX switch to theAUX position. Refer to figure 4.

Balance ControlAdjust the BALANCE control as needed to achieve ap-proximately equal listening volume levels in each loud-speaker. Turn the BALANCE to the left to emphasize theLeft Channel by reducing the level of the Right Channel.Turn the BALANCE to the right to emphasize the RightChannel by reducing the level of the Left Channel.

Equalizer ControlsEach of the five Equalizer Frequency Controls will raise orlower by approximately12dB, the amplitude of the band offrequencies centered at the frequency marked above thecontrols. Both Left and Right Channels are affected. Referto figure 5. At the center detent or flat position of the con-trols, all equalizer circuit components are removed from thesignal path.

Loud SwitchPress the LOUD push-button to add loudness bass com-pensation to the volume control for improved low level lis-tening.

MonoPress the MONO push-button to combine left and right ste-reo signals to mono at the SPEAKERS 1 and 2 and HEAD-PHONES output.

MutePress the MUTE push-button to mute audio in all outputsexcept the HEADPHONES and TAPE OUTPUT. TheMUTE LED above the push-button will flash on and off toindicate that Mute is active. To unmute audio, pressMUTE, press the Remote Control Volume push-button(s)or press an Input push-button.

Figure 1

Figure 3

Figure 4

Figure 5

Figure 2

14

How to Operate, con’t

Outputs 1 and 2Press OUTPUTS Push-button 1 to switch the Speakers Onor Off. Thepush-buttonsalso switch thePreamplifierOUTPUTS 1and 2 On or Offfor connection to external Power Amplifier(s). Press eitherpush-button individually, or both together. Refer to figure6.

Headphones JackConnect a pair of dynamic headphones to the HeadphonesJack for private listening. Press Mute to mute all other out-puts including the amplifier connected to the loudspeakers.Refer to figure 6.

Reset of MicroprocessorsIn the event that the controls of the MA6900 stop function-ing, push the POWER switch OFF and wait about two min-utes. Then push the POWER switch ON followed by push-ing the STANDBY/ON push-button. This will reset theMA6900 microprocessors and the Integrated Amplifiershould be functioning normally.

Note: The above condition is usually caused by eitherinterruptions in AC power and/or major changes thatmay occur in AC power line voltage.

Using a Separate Power AmplifierThere are two different ways to use a separate power am-plifier with a MA6900. The first wayis to use the separate amplifier insteadof the MA6900 built-in Power Ampli-fier. Connect the loudspeakers to theseparate power amplifier and removethe McIntosh Jumpers that are locatedbetween the OUTPUTS 1 Jacks andthe POWER AMP INput Jacks. Refer to figures 7 and 8.

Note: The McIntosh Jumpers must be connected, between theabove mentioned jacks, when the MA6900 InternalPower Amplifier is to be used.

The second way is to use both a sepa-rate power amplifier and the MA6900built-in Power Amplifier. Connect onepair of loudspeakers to the separatepower amplifier and the second pair tothe MA6900.

Note: The MA6900 VOLUME Control will affect the soundlevel of all the loudspeakers.

How To Make A Tape Recording1. Select the source signal you wish to record with the

appropriate Front Panel input push-button. If you wishto record from an Audio/Video source connected to theoptional McIntosh Audio/Video Selector Audio/VideoSelector, using the Remote Control, select the desiredsource connected to the McIntosh Audio/Video Selec-

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 MetersThe MA6900 Power Output Meters indicate the power de-livered to the loudspeakers. The meters respond to all themusical information being produced by the amplifier. Theyindicate to an accuracy of at least 95% of the power outputwith only a single cycle of a 2000Hz tone burst.

Figure 6

No Jumpers

Figure 8

Jumpers

Figure 7

Figure 9

15

Notes

16

Remote Control Push-Buttons

Selects one of the twelveHigh Level Audio/VideoSources or Phono Input

Turns AC Power ON or OFF to cer-tain McIntosh Components whenconnected via the Data Port

Adjusts the volumelevel up or down

Selects Disc Player, MusicServer or Tape RecorderFunctions and also per-forms various functionson a variety of McIntoshComponents

Press to Power theMA6900 ON or OFF

Use to select tuner pre-sets, disc tracks or anynumbered operation

Selects Switched Output2, FM Tuner OperatingFunctions and Track Se-lection on certain McIn-tosh CD Players

Mutes the audio

Note: Push-buttons whose function is notindentified above are for use withother McIntosh Products.

Press MODE to switch betweenStereo or Mono Modes

Selects Switched Output 1,AM Tuner Operating Func-tions and Disc Selection oncertain McIntosh CD Players

Selects On Screen Func-tions for McIntosh DVDPlayers and certain CDPlayers

Press TRIM to turn theLoudness Control Onor Off

Selects the FF (Fast For-ward) or REWind Modeon Disc Player, MusicServer or Tape Recorder;tunes Up or Down theAM/FM Dial

Selects Functions for McIntoshHome Controller and as a “shift”key when used with the AM or FMpush-buttons to select Output(Spkr) 1 or 2

Press to REVIEW Tuner StationPresets and selects certain func-tions on McIntosh CD Players

LED illuminates during thetime a remote command issent to the MA6900

Press to Power ONthe MA6900

Press to Power OFFthe MA6900

Switches OFF the entireMA6900 System

17

How to Operate by Remote Control

The supplied remote control is capable of directly control-ling the functions of contemporary McIntosh Source Com-ponents connected to the MA6900. Earlier McIntoshsource components and other brand source components canbe controlled by the MA6900 Remote Control with the ad-dition of a McIntosh Remote Control Translator (RCT).

Note: Your McIntosh Dealer can assist you with theinstallation and operation of the Remote ControlTranslator (RCT).

MutePress the MUTE push-button to mute audio at the Pream-plifier OUTPUTS 1, 2 and Speaker L, R OUTPUTs. TheTAPE OUTPUTS and HEADPHONES output are not af-fected by the MUTE function. The MUTE LED above thepush-button will flash on and off to indicate that Mute isactive. Press MUTE a second time to unmute audio.

MonoPress the MODE push-button to combine left and right ste-reo signals to mono at the Preamplifier OUTPUTS 1, 2 andSpeaker L, R OUTPUTs.

TrimPress the TRIM push-button to active the Loudness Com-pensation circuit.

Input Source SelectionPress any of the twelve input push-buttons to select a pro-gram source. When one of the Audio/Video Inputs (SAT,LV, TV, VCR, VCR2 and DVD) are selected by remotecontrol, the MA6900 will automatically switch to theVIDEO Input. If the Front Panel VIDEO Push-button ispressed, the source device connected to the VIDEO INPUTJacks will be heard. When the optional McIntosh MVS Au-dio/Video Selector is added, multiple Audio/Video InputsSources, such as LV, TV, VCR, VCR2 and DVD (V-Aux),will become available by just pressing the desired programsource push-button on the remote control.

Disc Player, Music Server or Tape RecorderFunctionsUse these push-buttons to operate a CD player, CDchanger or tape recorder.

Numbered Push-buttonsPress push-buttons 0 through 9 to access tuner station pre-sets or CD tracks/discs.

Disc and TrackUse the DISC and TRACK push-buttons when a DiscPlayer, Music Server or Tape Recorderexis being used.

Tuner Push-buttonsPress the AM or FM push-button to select the desiredbroadcast band. Press and release the CHANnel Up orDown push-button to move from station to station. Pressand hold a CHANnel Up or Down push-button tomove continuously from station to station. Press the +10Push-button to start the automatic brief audition of each ofthe presets stored in the tuner memory. Press the +10Push-button a second time to stop on a station preset andexit the review process.

VolumePress the Up or Down VOLUME push-button to raise orlower the listening volume level.

Note: The TAPE OUPUTS are not affected by volumechanges.

Amplifier SelectionPress the 2nd push-button followed by the OUTPUT 1 or 2push-buttons to control the rear panel OUTPUTS 1, 2which can feed signals to a power amplifier or other acces-sory component.

Acc OnPress ACC ON to turn the power ON to a McIntosh DiscPlayer.

Acc OffPress ACC OFF to turn the power OFF to a McIntosh DiscPlayer.

PausePress to perform various functions on a variety of McIn-tosh Components. It will also pause the playing of a disc ortape player.

How to Operate by Remote Control

18

Technical Description

McIntosh Laboratory, the company who introduced theworld’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 mostadvanced McIntosh circuit design concepts.

A continuous average power output rating of 200 wattsand with an output current of greater than 50 amperes perchannel, making this the most advanced Integrated Ampli-fier McIntosh has ever manufactured. The distortion limitsfor the MA6900 are no more than 0.005% at rated poweroutput for all frequencies from 20Hz to 20,000Hz. Typicalperformance at mid frequencies is less than 0.002%. Thetrue distortion readings on the MA6900 are so low, it takesspecial measuring techniques to make accurate readings.The MA6900 can deliver the best possible performancefrom any type of high quality loudspeaker system.

Creating an amplifier with this level of performance didnot 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 finaldesign was accepted.

Preamplifier Design PhilosophyAll signal switching in the MA6900 is done by Electro-Magnetic devices. Electro-Magnetic Switching is a proventechnology that uses the latest in materials and manufactur-ing methods. Each switch consists of a glass tube that isfilled with an inert oxygen-free atmosphere and sealedwith tiny leads protrudingfrom either end. These leadsextend into the tube andoverlap one another with aseparation of a few thou-sandths of an inch. The leadsare made from a ferrous ma-terial that is influenced by amagnetic field. They are firstplated with gold as a basematerial, then with rhodiumand finally ruthenium. Ru-thenium is the best contactmaterial known.

The glass assembly isthen placed in the center of amultilayer coil of copperwire. The entire assembly ismolded together in a toughshock absorbing material.

Bottom Inside View of the MA6900

The switch and coil connectors extend from the bottom inthe form of printed circuit board terminals. When a DCvoltage is applied to the coil, current flows and creates a

Equalizer Control Adjustment Range

Hz (Hertz)

dB(Decibel)

Figure 10

19

Technical Description

magnetic field. The force of the field causes the leads tobend and contact one another inside the sealed glass tube.The inert gas eliminates corrosion of the contacts and in-sures a low resistance, distortion free switch.

All inputs, outputs, and data ports are controlled bylogic circuits in the MA6900. The logic is changed by frontpanel push-buttons or by a microprocessor IR decoder.This microprocessor IR decoder is programmed with ex-clusive McIntosh software. It receives data from the frontpanel or external sensors and provides the command sig-nals for input switching, data switching, and volume con-trol.

The equalizer section uses several high technology op-erational amplifiers. The amplifier stage has been opti-mized for the best transient performance and minimum dis-tortion. Five other operational amplifiers are arranged in acircuit configuration that is the equivalent of a series turnedcircuit. A control potentiometer inserts this series tuned cir-cuit into either the feedback or input section of the equal-izer amplifier. This provides a 12dB boost or cut at the fre-quency of the tuned circuit. Refer to figure 10. The overallgain of the stage is 0dB when the potentiometer is at itscenter detent position. In this position the tone control ele-ments are completely removed from the signal path.

Power Amplifier Design PhilosophyThe design philosophy incorporated in the MA6900 in-volved several different techniques, all based on sound sci-entific logic. Refer to figure 11. Every stage of voltage orcurrent amplification must be as linear as possible prior tothe use of negative feedback. McIntosh engineers knowhow to properly design negative feedback circuits so theycontribute to the extremely low distortion performance ex-pected from a McIntosh amplifier. The typical McIntoshowner would never accept the approximately 100 timeshigher 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 activeregion 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 inthe unique McIntosh MA6900 Output Autoformer. It pro-vides low distortion power transfer at frequencies from be-low 20Hz to well beyond 20,000Hz with optimum imped-

Figure 11

Block Diagram of the Amplifer and Meter Circuitry

20

Input Test Signal

Figure 14

Without Power Guard

Figure 15

Top Inside View of the MA6900

Figure 12

Figure 13

ance points of two ohms, four ohms and eight ohms. Theunequaled expertise of McIntosh in the design and manu-facturing of autoformers is legendary in the high fidelityindustry.

The high efficiency circuit design of the MA6900 con-tributes to low operating temperatures. More than 621square inches of heat sink area keep the MA6900 operatingsafely with convection cooling. No fans are needed.

AutoformersAll solid state power amplifier output circuits work bestinto what is called an optimum load. This optimum loadmay vary considerably from what a loudspeaker requires.In the case of more than one loudspeaker connected in par-allel, the load to thepower amplifier maydrop to two ohms oreven less. A power am-plifier connected to aload that is lower thanoptimum, causes moreoutput current to flow,which results in extraheat being generated inthe power output stage.This increase in tem-perature will result in areduced life expectancyfor the amplifier.

The Autoformer creates an ideal match between thepower amplifier output stage and the loudspeaker. Refer tofigure 12. There is absolutely no performance limitationwith an Autoformer. Its frequency response exceeds that ofthe output circuit itself, and extends well beyond the au-dible range. Its distortion level is so low it is virtually im-possible to measure. In the rare event of a power amplifieroutput circuit failure, the McIntosh Autoformer providesabsolute protection from possible damage to your valuableloudspeakers.

Protection CircuitsThe MA6900 incorporates it’s version of the McIntoshSentry Monitor output transistorprotection circuit. Refer to figure13. There is absolutely no compro-mise in sonic performance withthis circuit, and it ensures safe op-eration of the amplifier under eventhe most extreme operating condi-tions. The different types of pro-tection circuits incorporated in theMA6900 insure a long and safe operating life.

The MA6900 also includes the unique patented McIn-tosh Power Guard circuit.Power Guard eliminates thepossibility of ever overdrivingthe amplifier into clipping. Re-fer to figures 14, 15 and 16. Anoverdriven amplifier can pro-duce both audible and inaudibledistortion levels exceeding40%. The audible distortion isunpleasant to hear, but the inau-dible ultrasonic distortion isalso undesirable, since it candamage valuable loudspeakersystem tweeters. You will neverexperience the harsh and dam-aging distortion due to clipping.

The Power Guard circuit is awaveform comparator, monitor-ing both the input and outputwaveforms. Under normal oper-ating conditions, there are nodifferences between the shapeof these waveforms. If an am-plifier channel is overdriven,there will be a difference between the two signal wave-forms. When the difference exceeds 0.3% (equivalent to0.3% harmonic distortion), the Power Guard activates the

21

Figure 16

With Power GuardPG light and a dynamic elec-tronic attenuator at the amplifierinput reduces the input volumejust enough to prevent any fur-ther increase in distortion. ThePower Guard circuit acts so fastthat there are absolutely no au-dible side effects and the sonicpurity of the music reproductionis perfectly preserved. TheMA6900 Amplifier with PowerGuard is not limited to just therated power output, but will actually produce distortionfree output well above its rated power due to the McIntoshphilosophy of conservative design.

Power Supply CircuitsTo compliment the design of the MA6900, there is a highvoltage power supply for both channels. Refer to figure 17.The power amplifiers draw high current from the ACpower line. Therefore, it is important that they plug directlyinto the wall outlet. Turn on inrush current is cushioned bythermistors in the power transformer’s primary circuit.This soft start eliminates component stress during turn-on.

The MA6900 can provide greater than 50 amperes peakoutput current to drive uneven speaker loads. Some poorspeaker designs have input impedance that dip to 1 or 2ohms at various frequencies and the MA6900 has the out-put current reserve to drive them. The MA6900 has mainfilter capacitors that guarantee an excellent signal to noiseratio and the energy storage necessary for the wide dy-namic range that “Digital Audio” demands.

Figure 17

Block Diagram of the Power Supply

22

Specifications

Specifications

Power OutputMinimum sine wave continuous average power output perchannel, all channels operating is:200 watts into 2 ohm load200 watts into 4 ohm load200 watts into 8 ohm load

Rated Power Band20Hz to 20,000Hz

Total Harmonic DistortionMaximum Total Harmonic Distortion at any powerlevel from 250 milliwatts to rated power output is:0.005% for 2, 4 or 8 ohm loads

Dynamic Headroom2.4dB

Frequency Response+0, -0.5dB from 20Hz to 20,000Hz+0, -3dB from 10Hz to 100,000Hz

SensitivityPhono, 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 Input100dB (90dB IHF) below rated output, High Level110dB below rated output, Power Amplifier

Intermodulation DistortionMaximum Intermodulation Distortion if instanta-neous peak output per channel does not exceedtwice the rated output, for any combination of fre-quencies from 20Hz to 20,000Hz, with all channelsoperating is:0.005% for 2, 4 or 8 ohm loads

Input ImpedancePhono, 47K ohms, 65pFHigh Level, 22K ohms

Maximum Input SignalPhono, 90mVHigh Level, 8V

Preamplifier Maximum Voltage OutputPhono, 8V at tape outputHigh Level, 8V at tape outputMain Out, 8V at preamp output

Voltage GainHigh Level to Tape: 0dBHigh Level to Main: 20dB

Wide Band Damping FactorGreater than 40

Power Requirements100 Volts, 50/60Hz at 5.2 Amps110 Volts, 50/60Hz at 4.8 Amps120 Volts, 50/60Hz at 4.4 Amps220 Volts, 50/60Hz at 2.45 Amps230 Volts, 50/60Hz at 2.35 Amps240 Volts, 50/60Hz at 2.25 Amps

Note: Refer to the rear panel of the MA6900 for the correctvoltage.

Overall DimensionsFront Panel: 17-1/2 inches (44.45cm) wide, 7-1/8 inches(18.10cm) high. Depth behind front mounting panel is 16-1/2 inches (41.91cm). Clearance required in front of theFront Panel is 1 inch (2.54cm) for knobs.

Weight74.5 pounds (33.8 Kg) net, 92.5 pounds (41.7 Kg) in ship-ping carton

23

Packing Instructions

Packing Instructions

In the event it is necessary to repack the equipment forshipment, the equipment must be packed exactly as shownbelow. It is very important that the four plastic feet are at-tached to the bottom of the equipment. Three #10 x 2-1/4inch screws and washers must be used to fasten the unitsecurely to the bottom pad and wood skid. This will ensurethe proper equipment location on the bottom pad. Failure todo this will result in shipping damage.

Use the original shipping carton and interior parts onlyif they are all in good serviceable condition. If a shippingcarton or any of the interior part(s) are needed, please callor write Customer Service Department of McIntosh Labo-ratory. Please see the Part List for the correct part numbers.

Quantity Part Number Description1 033888 Shipping carton only2 033887 End cap (Foam pad)

1 033697 Inside carton only1 033725 Top Pad1 034008 Bottom pad2 017218 Plastic foot (spacer)1 033699 Wood skid2 101204 #10 x 2-1/4 inch Wood screw2 104033 #10 x 1-3/4 inch Flat washer

4 017218 Plastic foot4 100159 #10-32 x 3/4 inch Machine

screw4 104083 #10 x 7/16 inch Flat washer

1 048572 Sipping Carton Complete

McIntosh Part No. 04099100

McIntosh Laboratory, Inc.2 Chambers Street

Binghamton, NY 13903

The continuous improvement of its products isthe policy of McIntosh Laboratory Incorporatedwho reserve the right to improve design withoutnotice.

Printed in the U.S.A.