McIntosh MC303 Three Channel Power Amplifier ... - TransTec

Power AmplifierMC303Owner’s ManualMcIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 www.mcintoshlabs.com

Connector Information, Introduction and Performance FeaturesGeneral Information, con’t6. When discarding the unit, comply with local rulesor regulations. Batteries should never be thrownaway or incinerated but disposed of in accordancewith the local regulations concerning battery disposal.7. For additional information on the MC303 and otherMcIntosh Products please vist the McIntosh WebSite at www.mcintoshlabs.com.8. When the MC303 is operated in the USA or Canada and themain fuse, located on the rear panel, is in need of replacementuse only the following part:Bussman ABC-15-R or Littlefuse 314-015PConnector and Cable InformationXLR ConnectorsBelow is the Pin configuration for the XLR Balanced InputConnectors on the MC303. Refer to the diagram for connection:PIN 1: Shield/GroundPIN 2: + OutputPIN 3: - OutputPower Control ConnectorThe MC303’s Power Control Inputs receive On/Off signalsof +5 volts. An additional connectionis for controlling the illumination of PowerControlthe MC303 Power Output Meters.MeterThe 1/8 inch stereo mini phone plug Illuminationconnects to a McIntosh A/V Control ControlGroundCenter Power Control Output.Note: The Power Control Connecting Cable is available fromthe McIntosh Parts Department:Data and Power Control Cable Part No. 170-202Six foot, shielded 2 conductor, with 1/8 inch stereo miniphone plugs on each end.IntroductionNow you can take advantage of traditional McIntoshstandards of excellence in the MC303 Power Amplifier.The 300 watt high current output per channel will driveany high quality loudspeaker system to its ultimate performance.The MC303 reproduction is sonically transparentand absolutely accurate. The McIntosh Sound is “TheSound of the Music Itself.”Performance FeaturesPIN 2 PIN 1PIN 3• Power OutputThe MC303 is a Power Amplifier with a capability of 300watts per channel (all channels driven) into 2, 4 or 8 ohmspeakers with less than 0.005% distortion. The Power Amplifiercircuitry uses Thermal Trak 1 Output Transistors forlower distortion and cool operation.• Balanced and Unbalanced InputsBalanced connections guard against induced noise and allowlong cable runs without compromising sound quality.• Power GuardThe patented McIntosh Power Guard circuit prevents theamplifier from being over driven into clipping, with itsharsh distorted sound that can also damage your valuableloudspeakers.• Sentry Monitor and Thermal ProtectionMcIntosh Sentry Monitor power output stage protectioncircuits ensure the MC303 will have a long and trouble freeoperating life. Built-in Thermal Protection Circuits guardagainst overheating.• Patented AutoformerMcIntosh 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 loudspeakers.• Special Power SupplyA regulated Power Supply, a very large Power Transformerand Capacitors ensure stable noise free operation eventhough the power line varies.• Illuminated Power MeterThe Illuminated Power Output Watt Meter on the MC303is peak responding, and indicates the power output of theamplifier. The Front Panel Meter Illumination may beswitched Off at any time.• Fiber Optic Solid State Front Panel IlluminationThe even illumination of the Front Panel is accomplishedby the combination of custom designed Fiber Optic LightDiffusers and extra long life Light Emitting Diodes(LEDs).• Glass Front Panel and Super Mirror Chassis FinishThe famous McIntosh Illuminated Glass Front Panel andthe Stainless Steel Chassis with Super Mirror Finish ensuresthe pristine beauty of the MC303 will be retained formany years.1ThermalTrak and ON Semiconductor are trademarks of SemiconductorComponents Industries, LLC4

DimensionsDimensionsThe following dimensions can assist in determining thebest location for your MC303. There is additional informationon the next page pertaining to installing the MC303into cabinets.17-3/4"45.09cmFront View of the MC30310-7/8"27.62cm12-3/8"31.43cm17-3/8"44.15cmRear View of the MC303F15AH 125V12-1/4"31.11cm1-5/8"4.12cm19-1/2"49.50cm18"45.72cmSide View of the MC3033/16"0.48cm10-1/2"26.70cm1-1/2"3.81cm14"35.60cm1-9/16"3.96cm5

InstallationInstallationThe MC303 can be placed upright on a table or shelf,standing on its four feet. It also can be custom installed ina piece of furniture or cabinet of your choice. The four feetmay be removed from the bottom of the MC303 when it iscustom installed as outlined below. The four feet togetherwith the mounting screws should be retained for possiblefuture use if the MC303 isremoved from the custominstallation and used freestanding. The requiredpanel cutout, ventilationcutout and unit dimensionsare shown.Always provide adequateventilation for yourMC303. Cool operationensures the longest possibleoperating life for anyelectronic instrument. Donot install the MC303 directlyabove a heat generatingcomponent such as ahigh powered amplifier. Ifall the components are installedin a single cabinet,a quiet running ventilationfan can be a definiteasset in maintaining allthe system components atthe coolest possible operatingtemperature.A custom cabinet installationshould provide thefollowing minimum spacingdimensions for cooloperation.Allow at least 6 inches(15.24cm) above the top,2 inches (5.08cm) belowthe bottom and 1 inch(2.54cm) on each side ofthe Power Amplifier, sothat airflow is not obstructed.Allow 19-1/2inches (49.53cm) depthbehind the front panel.Allow 1-5/8 inch (4.12cm)in front of the mountingpanel 1 for clearance. BeMC303 Front PanelCustom Cabinet CutoutMC303 Side Viewin Custom CabinetMC303 Bottom Viewin Custom CabinetCabinetFrontPanelOpeningfor VentilationSupportShelf21/32"1.67cmNote: Center the cutout Horizontally on the unit.For purposes of clarity, the aboveillustration is not drawn to scale.sure to cut out a ventilation hole in the mounting shelf accordingto the dimensions in the drawing.1When the MC303 is installed together with other McIntoshComponents, check clearances on all components beforeproceeding.6"15.24cm17-9/16"44.62cmCutout Opening for Ventilation1"2.54cm14-1/2"36.83cmCutout Openingfor Ventilation14"35.56cm10 -13/16"27.46cmCutout Opening for Custom MountingChassisSpacers15-5/16"38.91cm6

Rear Panel Connections and SwitchUNBALANCED INPUT 3for an audio cable from anA/V Control Center or Preamplifieraudio outputPOWER CONTROL INreceives turn On/Off signalfrom a McIntosh componentand the POWER CONTROLOUT sends a turn On/Offsignal to the next McIntoshComponentBALANCED INPUT 2for an audio cable froman A/V Control Centeror Preamplifier audiooutputBALANCED INPUT 1for an audio cable froman A/V Control Centeror Preamplifier audiooutputBALANCED INPUT 3for an audio cable froman A/V Control Centeror Preamplifier audiooutputUNBALANCED INPUT 2for an audio cable from anA/V Control Center or Preamplifieraudio outputUNBALANCED INPUT 1for an audio cable from anA/V Control Center or Preamplifieraudio outputF15AH 125VOUTPUT 3 Connectionsfor 2 ohm, 4 ohm or 8 ohmLoudspeakerOUTPUT 2 Connectionsfor 2 ohm, 4 ohm or 8 ohmLoudspeakerOUTPUT 1 Connectionsfor 2 ohm, 4 ohm or 8 ohmLoudspeakerConnect the MC303power cord to a live ACoutlet. Refer to the rearpanel to determine thecorrect voltageMain Fuse holder, refer to information onthe back panel of your MC303 to determinethe correct fuse size and rating. When usedin the USA and Canada refer to GeneralInformation note number 8 on page 4.7

How to Connect for Center and SurroundChannelsCaution: The supplied AC Power Cord should not beconnected to the Rear Panel of the MC303Amplifier until after the Loudspeaker Connectionshave been made. Failure to observe thiscould result in Electric Shock. For additionalinstruction on making Loudspeaker Connectionscontact your McIntosh Dealer or McIntoshTechnical Support.The connection instructions below, together with theMC303 Connection Diagram located on the separate foldedsheet “Mc1A, is an example of a typical audio/video system.Your system may vary from this, however the actualcomponents would be connected in a similar manner. Foradditional information refer to “Connector and Cable Information”on page 4.1. For Remote Power Control, connect a power controlcable from the A/V Control Center or PreamplifierPower Control Out to the Right Front Channel PowerAmplifier Power Control In. Connect a second powercontrol cable from the Right Front Channel PowerAmplifier Power Power Control Out to the Left FrontChannel Power Amplifier Power Control In.2. Connect a power control cable from the Left FrontChannel Power Amplifier Power Power Control Out tothe MC303 POWER CONTROL IN.3. Connect cables from the Balanced Outputs of the A/VControl Center or Preamplifier (Left and Right FrontChannels) to the Left and Right Front Power Amplifiers.Note: An optional hookup is to use the UNBALanced IN-PUTS with unbalanced cables instead of balanced.However, both type of connections for a given Inputshould not be used at the same time.4. Connect cables from the Balanced Outputs of the A/VControl Center or Preamplifier (Center and SurroundChannels) to the MC303 BALANCED INPUTs (1-3).When connecting Loudspeakers to the MC303 it is veryimportant to use cables of adequate size, so there is little tono power loss in the cables. The size is specified in GaugeNumbers or AWG (American Wire Gauge). The smallerthe Gauge number, the larger the wire size:Loudspeaker Cable Distance vs Wire Gauge GuideLoudspeakerImpedance25 feet(7.62 meters)or less50 feet(15.24 meters)or less100 feet(30.48 meters)or less2 Ohms 12AWG 10AWG 8AWG4 Ohms 14AWG 12AWG 10AWG8 Ohms 16AWG 14AWG 12AWG5. This McIntosh MC303 Power Amplifier is designed forthe connection of a single Loudspeaker per amplifierchannel, with an impedance of 2 ohms, 4 ohms or 8ohms.Note: The remaining Amplifier Loudspeaker Terminalsshould not be connected to another Loudspeaker.6. 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 togetheras tightly as possible.Note: If desired, thetwisted ends canFigure 1 Figure 2 Figure 3be tinned with solder to keep the strands together,or attach spade lug and/or banana connector.Spade lug or prepared wire connection:Insert the spade lug connector or prepared section ofthe cable end into the terminal side access hole, andtighten the terminalcap until the cable isfirmly clamped intothe terminal so thewires cannot slip out. Refer to figures 4, 5 & 6.Banana plug connection:Figure 4 Figure 5 Figure 6Insert the banana plug into the hole at the top of theterminal. Refer to figures A and B.Note: BananaPlugs arefor use inthe UnitedStates andCanadaonly.7. Connect the Loudspeaker hookup cables from a singleLoudspeaker to the output terminals that match theimpedance of OUPUT 1, being careful to observe thecorrect polarities. Output impedance connections of 2ohms, 4 ohms and 8 ohms are provided. If the Loudspeaker’simpedance is in-between the available connections,use the nearest lower impedance connection.Refer to “General Information” Note 5 on page 3 foradditional information.WARNING: Loudspeaker terminals are hazardous liveand present a risk of electric shock.8. In a similar manner, connect a Loudspeaker to OUT-PUT 2 and connect the remaining Loudspeaker toOUTPUT 3.9. Connect the MC303 Power Cord to a live AC outlet.8

Technical DescriptionMcIntosh Laboratory, the company who introduced theworld’s first amplifier that could be called “High Fidelity”,has done it again. The McIntosh engineering staff has createda power amplifier without compromise, using the mostadvanced McIntosh circuit design concepts.A continuous average power output rating of 300 wattsper channel and with an output current of greater than 60amperes per channel, making this one of the most advancedand powerful amplifiers McIntosh has ever manufactured.The distortion limits for the MC303 are no morethan 0.005% at rated power output for all frequencies from20Hz to 20,000Hz. Typical performance at mid frequenciesis less than 0.0002%. The true distortion readings on theMC303 are so low, it takes special measuring techniquesto make accurate readings. The MC303 can deliver thebest possible performance from any type of high qualityloudspeaker system.Creating an amplifier with this level of performance didnot come easily. Many months of design, testing and measuringwere required. Extensive controlled listening tests,the ultimate form of measuring, were made before the finaldesign was accepted.Inside Bottom View of the MC30312

16Top View of the MC303

SpecificationsSpecificationsPower OutputMinimum sine wave continuous average power output perchannel, all channels operating:300 watts into a 2 ohm, 4 ohm or 8 ohm loadOutput Load Impedance2, 4 or 8 ohmsRated Power Band20Hz to 20,000HzTotal Harmonic Distortion0.005% maximum harmonic distortion at any power levelfrom 250 milliwatts to rated power, 20Hz to 20,000HzDynamic Headroom1.8dBFrequency Response+0, -0.25dB from 20Hz to 20,000Hz+0, -3dB from 10Hz to 100,000HzInput Sensitivity (for rated output)1.7 Volt Unbalanced3.4 Volt BalancedPower Requirements100 Volts, 50/60Hz at 12 Amps110 Volts, 50/60Hz at 11 Amps120 Volts, 50/60Hz at 10 Amps220 Volts, 50/60Hz at 6 Amps230 Volts, 50/60Hz at 6 Amps240 Volts, 50/60Hz at 6 AmpsStandby: Less than 1 wattNote: Refer to the rear panel of the MC303 for the correctvoltage.Overall DimensionsWidth is 17-3/4 inches (45.09cm)Height is 12-3/8 inches (31.43cm) including feetDepth is 22 inches (55.88cm) including the Front Panel andCablesWeight155 pounds (70.3 kg) net, 180 pounds (81.6 kg) in shippingcartonShipping Carton DimensionsWidth is 31 inches (78.74cm)Depth is 28 inches (71.12cm)Height is 17-1/4 inches (43.82cm)Signal To Noise Ratio (A-Weighted)112dB below rated outputIntermodulation Distortion0.005% maximum, if the instantaneous peak power outputdoes not exceed twice the rated power output for any combinationof frequencies from 20Hz to 20,000Hz.Wide Band Damping FactorGreater than 40Input Impedance10,000 ohmsPower GuardLess than 2% THD with up to 14dB overdrive at 1,000HzPower Control Input5VDC - 12VDCPower Control Output12VDC, 25mA maximum, delay 0.2 seconds18

Packing InstructionsPacking InstructionsIn 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 feet are attached tothe bottom of the equipment. This will ensure the properequipment location on the bottom foam pad. Failure to dothis 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 Laboratory.Please see the Part List for the correct part numbers.Quantity Part Number Description1 034105 Shipping carton top1 034104 Shipping carton bottom2 034439 Foam Pad (top and bottom)3 034441 Foam Ring4 018445 Feet19

McIntosh Laboratory, Inc.2 Chambers StreetBinghamton, NY 13903www.mcintoshlabs.comThe continuous improvement of its products is thepolicy of McIntosh Laboratory Incorporated whoreserve the right to improve design without notice.Printed in the U.S.A.McIntosh Part No. 04109800