McIntosh MC302 audio amplifier
Contents
1. Cabinet Front Panel Cutout Opening for Custom Mounting Zu 6 Cabinet 15 24cm Front Panel Opening for Ventilation MC302 Side View in Custom Cabinet Support Shelf 3 Spacers 5 7 62cm _ MC302 Bottom View Se 12 31 in Custom Cabinet TUS 38cm 1 6 40 64cm Ss Cutout Opening for Ventilation Note Center the cutout Horizontally on the unit For purposes of clarity the above illustration is not drawn to scale Unbalanced INput LEFT and RIGHT Channels for an audio INPUT MODE switch cable from a Preamplifier or A V selects between Balanced Control Center audio output or Unbalanced Inputs Balanced INputs RIGHT and LEFT Channels for audio cables from a Pre amplifier or A V Control Center audio output IN INPUT MODE BALANCED UNBALANCED 120V u 60Hz 4 RIGHT OUTPUT 6 6 AMPS CLASS 2 WIRING McIntosh MC302 POWER AMPLIFIER McINTOSH LABORATORY INC BINGHAMTON NY 13903 MADE IN USA RIGHT OUTPUT Connections for a 2 ohm 4 ohm or 8 ohm Loudspeaker Connect the MC302 power cord to a live AC outlet Refer to the rear panel to determine the correct voltage POWER CONTROL OUT 1 OUT 2 10AH 250V 4 LEFT OUTPUT 4 CLASS 2 WIRING Rear Panel Connections and S2. protection circuits will activate The Front Panel Power Guard LEDs will continuously indicate ON and the audio will be muted When the MC302 has returned to a safe operating temperature normal operation will resume 6 When discarding the unit comply with local rules or regulations Batteries should never be thrown away or incinerated but disposed of in accordance with the local regulations concerning battery disposal 7 For additional information on the MC302 and other McIntosh Products please visit the McIntosh Web Site at www mcintosh labs com Nn al Connector and Cable Information XLR Connectors Below s the Pin configuration for the XLR Balanced Input on the MC302 Refer to the diagram for connec tion IN PIN 1 Shield Ground PIN 2 Input PIN 3 Input PIN 2 PIN 1 PIN 3 Power Control Connector The MC302 Power Control Input receives an On Off signal from 5 to 12 volts The Power Control Output will in turn provide a 12 volt Output Signal with a total cur Trigger rent up to 50mA An additional Control connection is for controlling Meter 7 Illumination the illumination of the MC302 Power Output Meters The 1 8 inch stereo mini phone plug connects to a McIntosh Preamplifier or A V Control Center Power Control Output Note The Power Control Connecting Cable is available from the McIntosh Parts Department Data and Power Control Cable Part No 170 202 Six foot shielded 2 conductor with 1 8 inch
3. 5V signal oper ates the power relay in the MC302 The MC302 also has two remote Power Control Out Jacks The Power Therefore it is important that they Control signal from these jacks are delayed by a frac plug oy tion of a second so that the turn on power surge of the into the wall next power amplifier occurs at a later time This helps outlet Figure 24 prevent power circuit overload that could trip circuit Also most breakers or blow fuses a very important feature in a high power Home Systems employing multiple MC302 Power Amplifiers owners desire one power switch for the whole audio system The MC302 is equipped with a circuit that provides remote Power Control from a McIntosh A V Control Center Refer to figure 25 When the A V Figure 23 Specifications Power Output Minimum sine wave continuous average power output per channel with both channels operating is 300 watts into 2 ohm load 300 watts into 4 ohm load 300 watts into 8 ohm load Output Load Impedance 2 4 or 8 ohms Rated Power Band 20Hz to 20 000Hz Total Harmonic Distortion 0 005 maximum harmonic distortion at any power level from 250 milliwatts to rated power 20Hz to 20 000Hz Dynamic Headroom 1 8dB Frequency Response 0 0 25dB from 20Hz to 20 000Hz 0 3 0dB from 10Hz to 100 000Hz Input Sensitivity for rated output 3 4 Volts Balanced 1 7 Volts Unbalanced Signal To Noise Ratio A Weighted 95dB Balanced 120dB below
4. stereo mini phone plugs on each end Control Ground Introduction TE Te vb Now you can take advantage of traditional McIntosh standards of excellence in the MC302 Power Amplifi er The 300 watts power per channel with high current output will drive any pair of high quality Loudspeak ers The MC302 reproduction is sonically transparent and absolutely accurate The McIntosh Sound is The Sound of the Music Itself Cable Information Introduction and Performance Features Performance Features e Power Output The MC302 s a Power Amplifier w th a capability of 300 watts per channel into 2 4 or 8 ohm speakers with less than 0 005 distortion The Power Amplifier Circuitry uses ThermalTrak Output Transistors for lower distortion and cool operation e Patented Autoformer McIntosh designed and manufactured Output Auto formers 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 e Balanced and Unbalanced Inputs Balanced connections guard against induced noise and allow long cable runs without compromising sound quality e Power Guard The patented McIntosh Power Guard circuit prevents the amplifier from being over driven into clipping with its harsh distorted sound that can also damage your valuable loudspeakers e Sentry Monitor and Thermal Protection McIntosh Sentry Monitor power out
5. BLE PARTS INSIDE REFER SERVICING TO QUALIFIED PERSONNEL 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 Protect the power cord from being walked on or pinched particularly at plugs convenience receptacles and the point where they exit from the apparatus Only use attachments accessories specified by the manufacturer Use only with the cart stand tripod bracket or table specified by the manu facturer or sold with the appa ratus When a cart is used use caution when moving the cart apparatus combination to avoid injury from tip over Unplug this apparatus during lightning storms or when unused for long periods of time Refer all servicing to qualified service person nel Servicing is required when the apparatus has been damaged in any way such as power 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 15 16 Li 18 19 To prevent the risk of electric shock do not remove cover or back No user serviceable parts inside supply cord or plug 1s damaged liquid has been spilled or objects have fallen into the apparatus the apparatus has been exposed to rain or moisture does not opera
6. EEUTOEREFUEUERUESECHERETENERNERENER 10 11 Front Panel Displays and Controls 12 How tO VCE ANG ee engen 13 Technical Deserplion ee 14 17 BS PCC UICAMIOMNS picai ironi iieiea keek iiai 18 Pack ne Instruct On nee 19 General Information 1 The following Connecting Cable is available from the McIntosh Parts Department Power Control Cable Part No 170 202 Six foot 2 conductor shielded with two 1 8 inch stereo mini phone plugs 2 For additional connection information refer to the owner s manual s for any component s connected to the MC302 3 The MC302 mutes the speaker output for approxi mately two seconds when first turned on 4 For the best performance and safety it is important to always match the impedance of the loudspeaker to the Power Amplifier connections Refer to How to Connect pages 8 thru 11 Note The impedance of a Loudspeaker actually var ies as the Loudspeaker reproduces different frequencies As a result the nominal impedance rating of the Loudspeaker usually measured at a midrange frequency might not always agree with the impedance of the Loudspeaker at low frequencies where the greatest amount of power is required Contact the Loudspeaker Manufac turer for additional information about the actual impedance of the Loudspeaker before connecting it to the McIntosh MC302 In the event the MC302 over heats due to improper ventilation and or high ambient temperature the
7. McIntosh Laboratory Inc 2 Chambers Street Binghamton New York 13903 2699 Phone 607 723 3512 www mcintoshlabs com 30 30 20 30 30 300 59 40 30 20 10 o Melntosh 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 en closure that may be of sufficient magnitude to constitute a risk of electric shock to persons SYN MN BW NY e WARNING TO REDUCE RISK OF FIRE OR ELECTRICAL SHOCK DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE IMPORTANT SAFETY INSTRUCTIONS PLEASE READ THEM BEFORE OPERATING THIS EQUIPMENT Read these instructions Keep these instructions Heed all warnings Follow all instructions Do not use this apparatus near water Clean only with a dry cloth Do not block any ventilation openings Install in accordance with the manufacturer s instruc tions Do not install near any heat sources such as radiators heat registers stoves or other appa ratus including amplifiers that produce heat Do not defeat the safety purpose of the polar ized 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 10 11 19 13 14 CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN A A AV S RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR NO USER SERVICEA
8. NSIDE BOX FOAM PAD SIDE 2X V Le x FOAM PAD FRONT AND REAR 2X SHIPPING CARTON BOTTOM McIntosh Laboratory Inc 2 Chambers Street Binghamton NY 13903 www mcintoshlabs com The continuous improvement of its products is the policy of McIntosh Laboratory Incorporated who reserve the right to improve design without notice Printed n the U S A McIntosh Part No 04123901
9. Refer to figure 12 Creating an amplifier with this level of perfor mance did not come easily Many months of design testing and measuring were required Extensive con trolled listening tests the ultimate form of measuring were made before the final design was accepted MeIntas BOWER TRANSFER Design Philosophy The design philosophy incorporated in the MC302 un involved several different techniques all based on I uw Se sound scientific logic Every stage of voltage or cur rent amplification must be as linear as possible prior to the use of negative feedback McIntosh engineers know how to properly design negative feedback cir Bann MC302 nonm f output per channel with both channels operating POWER AMPLIFIER FREQUENCY RESPONSE o oohz cuits so they contribute to the extremely low distortion ea 3 4 volts balanced performance expected from a McIntosh amplifier TOTAL LARMON DISTORTION o y Precision Performance By lltInfosh umaen sena zonose sano The typical McIntosh owner would never accept the a nn UNE approximately 100 times higher distortion of many Figure 12 14 Technical Description PG POWER INDICATOR GUARD UNBALANCED PU INPUT MODE SWITCH O BALANCED INPUT Q MUTE TURN ON DELAY POWER GUARD Ea BALANCED ATTENUATOR AMP Block Diagram of the Power Amplifier one channel shown non feedback designs Refer to figure 15 All transistors are selected to have n
10. ation If no further power peaks are reached the meter pointer will very slowly return to its rest position or lower power level The decay rate 1s approximately 6dB per minute Input Mode Switch The Input Mode Switch which 1s located on the Rear Panel of the MC302 allows selection of either the Bal INPUT MODE anced or Unbalanced Input BALANCED Refer to figure 11 UNBALANCED Figure 11 Me Technical Description x ee ee McIntosh Laboratory the company who introduced the world s first amplifier that could be called High 9 Y e oh C ei ee Fidelity has done it again The McIntosh engineering ji staff has created a power amplifier without compro mise using the most advanced McIntosh circuit design concepts The MC302 has a continuous average power output rating of 300 watts per channel with a peak output LPOUUU SPROUL eee current of 60 amperes making it one of the most LITER TIT advanced amplifiers available today The distortion TLL UIII limits for the MC302 are no more than 0 005 at LILIE LITE rated power output for all frequencies from 20Hz to III 20 000Hz Typical performance at mid frequencies is i l l i JRE less than 0 002 The true distortion readings on the I Banan MC302 are so low it takes special measuring tech niques to make accurate readings The MC302 can deliver the best possible performance from any type of high quality loudspeaker system
11. cIntosh Autoformer provides absolute protection from possible damage to your valuable loudspeakers The unequaled expertise of McIntosh in the design and manufacturing of Autoformers is legendary in the high fidelity industry McIntosh engi neers know how to do it right Figure 16 Power Output Meter The McIntosh MC302 has large Output Watt Meters that respond 95 full scale to a single cycle tone burst at 2kHz Refer to figure 17 The Voltage Output is electronically measured and fed to a special circuit that accelerates the pointer movement in the upward direction Refer to figure 25 on the next page 16 When the pointer reaches its peak ware it pauses only THOE E go A long enough for the human eye to perceive its posi tion then drops It is almost 10 times faster than a professional VU meter A front panel switch is provided to change the meter to the Watts Hold Mode of operation This allows fast upward movement of the pointer but greatly increases Hold Time at the peak of its travel The highest power out put of the source material is thus recorded POWER OUTPUT Figure 17 Protection Circuits The MC302 incorporates the McIntosh Sentry Moni tor Output Transistor Protection Circuit Refer to Figure 18 There is absolutely no compromise in sonic performance with this circuit and it ensures safe opera tion of the ampli fier under even the most extreme operating condi tions The diffe
12. e Power Figure 20 Technical Description con t Guard circuit acts so fast that there are absolutely no audible side effects and the sonic purity of the music reproduction 1s perfectly preserved The MC302 Power Amplifier with Power Guard is not limited to just the rated With Power Guard Block Diagram of the Power Supply BACKUP POWER SUPPLY POWER CONTROL CONTROL LOGIC LIGHTING POWER CONTROL SWITCH LOW VOLTAGE SUPPLY INRUSH power output but will AC Power O FUSE CURRENT MAIN RELAYS en H r actually produce distor LIMITER TRANSFORMER SUPPLY tion free output well above its rated power due to the McIntosh philosophy of conservative design Figure 21 Figure 22 It is enclosed in the legendary McIntosh Potted Enclo sures and weighs 28lbs The two super size main filter capacitors can store over 140 Joules of energy for both Power Supply Circuits amplifier channels necessary for the wide dynamic To compliment the design of the MC302 Power Am range that Digital Audio demands Refer to figure plifier Circuitry there is a high current high voltage 24 power supply for both channels Refer to figures 22 The power and 25 The very large Power Transfomer can supply amplifier over 13 amps of continuous current Refer to figure 23 draws high golf ball is for size comparison current from the AC Figure 25 power line Control Center is switched On a
13. e separate folded sheet Mic1A is an example of a typical audio system Your system may vary from this however the actual components would be connected in a similar manner For additional information refer to Connec tor and Cable Information on page 4 1 For Remote Power Control connect a power control cable from the Audio Preamplifier or A V Con trol Center Power Control Output 1 to the MC302 POWER CONTROL IN 2 Connect XLR cables from the Balanced Output 1 L amp R of an Audio Preamplifier or A V Control Center to the MC302 Balanced INput RIGHT and LEFT Place the INPUT MODE Switch in the BALANCED Position Note An optional hookup is to use unbalanced cables and place the INPUT MODE Switch in the UNBALANCED Position This McIntosh MC302 Power Amplifier is designed for Loudspeakers with an impedance of 2 ohms 4 ohms or 8 ohms Connect a single Loudspeaker only to the Right and Left Output Terminals When connecting Loudspeakers to the MC302 it is very important to use cables of adequate size so there is little to no power loss in the cables The size is specified in Gauge Numbers or AWG American Wire Gauge The smaller the Gauge number the larger the wire size Loudspeaker Cable Distance vs Wire Gauge Guide 25 feet 50 feet 100 feet Loudspeaker Impedance 7 62 meters 15 24 meters 30 48 meters or less or less orless 12AWG 10AWG 8AWG 10AWG 12AWG tonne ano awe tonne ra
14. early constant current gain over the entire current range they must cover Output transistors in particular have matched uniform current gain high current bandwidth prod uct and large active region safe operating area These Power Transistors are the very latest in semiconductor technology and incorporate a new design known as ThermalTrak Refer to figure 13 This allows for the instantaneous and accu rate monitoring of the Power Transistor Temperature The MC302 Power Output Circuitry has a specially designed bias cir cuit to take full advantage of the Thermal Trak Power Transistors and thus precise ly controls the power amplifier operation over a wide range of music conditions with the benefits of lower distortion and cooler operation Precision metal film resistors and low dielectric ab sorption film capacitors are used in all critical circuit locations Figure 13 CURRENT SOURCE considerably from what a loudspeaker requires In the case of more than one loudspeaker POSITIVE CURRENT LIMITER VOLTAGE LOG METER AMP METER HOLD SWITCH VOLTAGE er PREDRIVER OUTPUT OF 304m tam connected in parallel OF 3 oben the load to the power amplifier may drop to two ohms or even less A power ampli fier 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 temperat
15. her with the mounting screws should be retained for possible future use if the MC302 is removed from the custom installation and used free standing The required panel cutout ventila tion cutout and unit dimensions are shown Always provide adequate ventilation for your MC302 Cool operation ensures the longest possible operating life for any electronic instrument Do not install the MC302 directly above a heat generating component such as a high powered amplifier If all the compo nents are installed n a single cabinet a quiet running ventilation fan can be a definite asset in maintaining all the system components at the coolest possible oper ating temperature A custom cabinet installation should provide the fol lowing minimum spacing dimensions for cool opera tion Allow at least 6 inches 15 24cm above the top 2 inches 5 08cm below the bottom 3 inches 7 62cm behind the rear panel and 2 inches 5 08cm on each side of the Power Amplifier so that airflow is not obstructed Allow 7 8 inch 2 22cm in front of the mounting panel for clearance Be sure to cut out a ventilation hole in the mounting shelf according to the dimensions in the drawing When the MC302 is installed together with other McIn tosh Components check clearances on all components before proceeding Installation 17 a S 43 18cm ERST 14 11 16 ee 37 30cm MC302 Front Panel Custom Cabinet Cutout
16. imensions Dimensions The following dimensions can assist in determining the best location for your MC302 Front View of the MC302 17 1 2 n 44 45cm ATTS POWER GUARD RIGHT watts 30 30 30 30 30 300 a 40 30 20 fro OT DECIBELS POWER QUTPUT 3 0 30 30 _30 20 300 30 20 Tu POWER TPUT METER C302 POWER AMPLIFIER Rear View of the MC302 16 13 16 42 70cm 8 7 8 22 54cm 9 7116 23 97cm POWER CONTROL i Es EZ 4 RIGHT OUTPU CLASS 2 WIRI MC302 POWER AMPLIFIER McINTOSH LABK Q fe 20V 60Hz 10AH 250V 6 6 AMPS gt UE j N I CLASS 2 WIRING L 11 3 4 29 85cm Side View of the MC302 20 3 16 51 27cm u 17 1516 or 45 55cm 5 8 1 59cm 0 i oem 2 06cm 43 2 5 8 33 02cm 6 67cm 3 16 0 48cm En 8 3 8 21 27cm 2 3 16 5 55cm Me Installation The MC302 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 MC302 when it is custom installed as outlined below The four feet toget
17. king Instructions Packing Instructions a a E In the event it is necessary to repack the equipment for shipment the equipment must be packed exactly as shown below It is very important that the four plastic feet are attached to the bottom of the equipment Four 1 4 20x2 1 4 inch screws and washers must be used to fasten the unit securely to the bottom pad and wood skid This will ensure the proper equipment location on the bottom pad Failure to do this will result in shipping damage Use the original shipping carton and interior parts only if they are all in good serviceable condition If a shipping carton or any of the interior part s are needed please call or write Customer Service Depart ment of McIntosh Laboratory Refer to page 3 Please see the Part List for the correct part numbers Quantity Part Number Description l 034052 Shipping carton top l 034051 Shipping carton bottom 2 034054 Foam Pad top and bottom 2 034186 Foam Pad front and rear 2 034187 Foam Pad sides l 034136 Inner carton top 1 034137 Inner carton bottom 1 034188 Foam Pad inner carton l 034479 Shipping skid 4 401212 1 4 20x2 1 4 cap screw 4 104058 Flat washer INNER 7 CARTON TOP FOAM PAD x INNER CARTON SHIPPING_ 7 SKID IMPORTANT gt Read Above INNER CARTON BOTTOM nv Flat WASHER 4x 1 4 20 X 2 1 4 CAP SCREW 4x SHIPPING CARTON TOP FOAM PAD TOP AND BOTTOM 2X SO I
18. nal one quarter of a turn 90 Do not over tighten Refer to figure E Referring to figure H connect the Loudspeaker hookup cables with banana plugs into the hole at the top of the terminal to the MC302 COM Negative Output Terminal and Positive Output Terminal indentified as 2Q ohms 4Q ohms or 8Q ohms connection to match the impedance of the Loudspeaker being careful to observe the correct polarities Note The illustration on separate sheet Mc1B is connections for 8Q ohms Loudspeakers If the Loudspeaker s impedance is in between the available connections use the nearest lower imped ance connection Refer to General Information Note 4 on page 3 for additional information WARNING Loudspeaker terminals are hazard ous live and present a risk of electric Shock For additional instruction on making Loudspeaker Connections con tact your McIntosh Dealer or McIn tosh Technical Support Figure H 9 Connect the MC302 power cord to an active AC outlet Spade Lug or Wire Connections 10 Connect the Loudspeaker hookup cables to the MC302 Negative Output Terminal and Positive Output Terminal indentified as 2Q ohms 4Q ohms or 8Q ohms connection to match the impedance of the Loudspeaker being careful to l1 Output Terminals and How to Connect for Bi Amp observe the correct polarities Insert the spade lug connector or prepared section of the cable end into the terminal side access h
19. ole and tighten the terminal cap until the cable is firmly clamped into the terminals so the lugs or wire cannot slip out Refer to figures 7 and 8 Figure 7 Figure 8 Note The illustration on separate sheet Mc1B is connections for 8Q ohms Loudspeakers If the Loudspeaker s impedance is in between the available connections use the nearest lower impedance connection Refer to General Informa tion Note 4 on page 3 for additional information WARNING Loudspeaker terminals are hazard ous live and present a risk of electric Shock For additional instruction on making Loudspeaker Connections con tact your McIntosh Dealer or McIn tosh Technical Support Connect the MC302 power cord to an active AC outlet 11 Ic Front Panel Displays and Controls Meter indicates the Standby Power Meter indicates the _ Pride ner LED indicates when the RIGHT nn er a P Channel Amplifier POWER Channel Amplifier POWER P GUARD circuit activates GUARD circuit activates 50 30 O 30 Re POWER GUARD 40 30 20 u oo Oo LEFT RIGHT 50 DECIBELS DECIBELS METER POWER WATTS REMOTE LIGHTS OFF HOLD t nfo 5 h OFF ON MC302 POWER AMPLIFIER Oo y No o i y o METER Switch selects POWER Switch Turns AC Power Off the display modes of the Remote AC Power On Power Output Meter and Meter Illumination 12 How to Operate How to Operate Power On To have the MC302 automatically tu
20. pade 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 terminals so the lugs or wire cannot slip out Refer to figures 7 and 8 Figure 7 Figure 8 Output Terminals en sn A ae When connecting the Loudspeaker Hookup Cables to the MC452 Power Amplifier Output Terminals please follow the steps below 1 Rotate the top of the Output Terminal Post coun terclockwise until an opening appears Refer to figures A and B 2 Insert the Loudspeaker hookup cable into the Output Terminal Post opening or the cable spade lug around the center post of the Output Terminal Refer to figure C 3 Rotate the top of the Output Terminal Post clockwise until it is finger tight Refer to figure D 4 Place the supplied McIntosh Wrench over the top of the Out put Terminal and rotate it one quarter of a turn 90 to secure the Loudspeaker Cable Connec tion Do not over tighten Refer to figure E Figure B Figure A Figure C Figure E How to Connect for Bi Am Caution Do not connect the AC Power Cord to the MC302 Rear Panel until after the Loudspeaker Connections are made Failure to observe this could result in Electric Shock The connection instructions below together with the MC302 Connection Diagram located on the separate folded sheet Me1B is an example of a typical audio sys
21. put stage protec tion circuits ensure the MC302 will have a long and trouble free operating life Built in Thermal Protection Circuits guard against overheating e Special Power Supply A very large Power Transformer and Large Capac tors ensure stable noise free operation even though the power line varies ThermalTrakTM and ON Semiconductor are trademarks of Semi conductor Components Industries LLC e Illuminated Power Meters The Illuminated Power Output Watt Meters on the MC302 are peak responding and indicate the true power output of the amplifier The Peak Watt Hold Mode allows the meter to temporarily stay at the high est power output and then slowly decay The Front Panel Meter Illumination may be switched Off at any time e McIntosh Custom Binding Posts McIntosh patent pending gold plated output terminals deliver high current output They accept large diam eter wire and spade lugs Banana plugs may also be used only in the United States and Canada e Fiber Optic Solid State Front Panel Illumination The even Illumination of the Front Panel is accom plished by the combination of custom designed Fiber Optic Light Diffusers and extra long life Light Emit ting Diodes LEDs e Glass Front Panel and Super Mirror Chassis Finish The famous McIntosh Illuminated Glass Front Panel and the Stainless Steel Chassis with Super Mirror Fin ish ensures the pristine beauty of the MC302 will be retained for many years D
22. rated output 93dB Unbalanced 118dB below rated output 18 Intermodulation Distortion 0 005 maximum if the instantaneous peak power output does not exceed twice the rated power output for any combination of frequencies from 20Hz to 20 000Hz Wide Band Damping Factor Greater than 40 Input Impedance 22 000 ohms Balanced 22 000 ohms Unbalanced Voltage Gain 29dB 8 Ohms 26dB 4 Ohms 23dB 2 Ohms Power Guard Less than 2 Total Harmonic Distortion with up to a 14dB overdrive signal Power Control Input 5 ISVDC less than ImA Power Control Output 1 and 2 12VDC 50mA maximum total Output is delayed 0 2 seconds from turn On Specifications Power Requirements Field AC Voltage conversion of the MC302 is not possible The MC302 ts factory configured for one of the following AC Voltages 100V 50 60Hz at 8 Amps 110V 50 60Hz at 6 6 Amps 120V 50 60Hz at 6 6 Amps 220V 50 60Hz at 3 6 Amps 230V 50 60Hz at 3 3 Amps 240V 50 60Hz at 3 3 Amps Standby less than 0 5 watt Note Refer to the rear panel of the MC302 for the cor rect voltage Overall Dimensions Width is 17 1 2 inches 44 45cm Height is 9 7 16 inches 23 97cm including feet Depth is 22 inches 55 88cm including the Front Panel Knobs and Cables Weight 98 pounds 44 45 kg net 131 pounds 59 42 kg in shipping carton Shipping Carton Dimensions Width is 29 1 2 inches 74 93cm Depth is 29 inches 73 66cm Height is 17 inches 43 18cm Pac
23. rent types of protection circuits incorpo rated in the MC302 insure a long and safe operating life This is just one of the many characteristics of McIntosh Power Ampli fiers that make them world famous Normal Operating Area Sentry Monitor Safety Area Output Transistor Failure Figure 18 The MC302 also includes the unique patented McIntosh Power Guard circuit Power Guard elimi nates the possibility of ever overdriving the ampli fier into clipping Refer to figures 19 20 and 21 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 also undesir able since it can damage valuable loudspeaker system tweeters You will never experience the Input Test Signal 14kHz amp 15kHz harsh and damaging dis tortion due to clipping The Power Guard Figure 19 circuit is a waveform Without Power Guard comparator monitoring both the input and out put waveforms Under normal operating condi tions there are no differ ences between the shape of these waveforms If an amplifier channel is overdriven there will be a difference between the two signal waveforms When the difference exceeds 0 3 the Power Guard activates the PG light and a dynamic electronic attenuator at the ampli fier input reduces the input volume just enough to prevent any further increase in distortion Th
24. rn On or Off when a control center turns on or off rotate the power switch to the Remote position For manual operation rotate the power switch to the On or Off position as desired Refer to figure 8 Note There must be a power control connection between the MC302 and the Audio Preamplifier or A V Con trol Center in order for the remote power turn on to Figure 8 function POWER REMOTE OFF ON Meter Selection Rotate the meter mode switch to select the meter operation mode you desire Refer to figures 9 and 10 Lights Off Meter lights BE are turned off Lients ofr HOLD and the meter will continue to indicate the power output Note When Power Control Input of the MC302 is connected to a Audio Preampli fier or A V Control Center with Remote Meter Illumination Con trol the Meter Illumination will automatically be remotely con trolled On Off with the METER Switch set to the WATTS or HOLD position METER Figure 9 DECIBELS POWER QUTPUT Figure 10 Watts The meters respond to all the musi cal 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 Hold The meter pointer is locked to the high est power peak in a sequence of peaks It is electronically held to this power level until a higher power peak passes through the amplifier The meter point er will then rise to the newer higher indic
25. te normally or has been dropped 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 To completely disconnect this equipment from the a c mains disconnect the power supply cord plug from the a c receptacle The mains plug of the power supply cord shall remain readily operable Do not expose batteries to excessive heat such as sunshine fire or the like Connect mains power supply cord only to a mains socket outlet with a protective earthing connection Thank You Your decision to own this McIntosh MC302 Power Amplifier ranks you at the very top among discrimi nating 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 pos sible with all the features and functions of your new McIntosh Please Take A Moment E 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 an
26. tem Your system may vary from this however the actual components would be connected in a similar manner For additional information refer to Connec tor and Cable Information on page 4 10 1 For Remote Power Control connect a power control cable from the Audio Preamplifier or A V Con trol Center Power Control Output 1 to the MC302 POWER CONTROL IN Amplifier One 2 Connect a power control cable from the Audio Preamplifier or A V Control Center Power Control Output 2 to the MC302 POWER CONTROL IN Amplifier Two 3 Connect XLR cables from the Balanced Output 1 L amp R ofan Audio Preamplifier or A V Control Center to the MC302 Balanced INput RIGHT and LEFT on Amplifier One Place the INPUT MODE Switch in the BALANCED Position Note An optional hookup is to use unbalanced cables and place the INPUT MODE Switch in the UNBALANCED Position 4 Connect XLR cables from the Balanced Output 2 L amp R of a Audio Preamplifier or A V Control Center to the MC302 Balanced INput RIGHT and LEFT on Amplifier Two Place the INPUT MODE Switch in the BALANCED Position Note An optional hookup is to use unbalanced cables and place the INPUT MODE Switch in the UNBALANCED Position This McIntosh MC302 Power Amplifier is designed for Loudspeakers with an impedance of 2 ohms 4 ohms or 8 ohms Connect a single Loudspeaker only to the Right and Left Output Terminals When connecting Loudspeakers to the MC302 it is very important to
27. tration on separate sheet MclA is connections for 8Q ohms Loudspeakers If the Loudspeaker s impedance 1s in between the available connections use the nearest lower impedance connection Refer to General Informa tion Note 4 on page 3 for additional information WARNING Loudspeaker terminals are hazard ous live and present a risk of electric Shock For additional instruction on making Loudspeaker Connections con tact your McIntosh Dealer or McIn Note The illustration on separate sheet Mcl1A is connections for 8Q ohms Loudspeakers If the Loudspeaker s impedance is in between the available connections use the nearest lower impedance connection Refer to General Informa tion Note 4 on page 3 for additional information WARNING Loudspeaker terminals are hazard ous live and present a risk of electric Shock For additional instruction on making Loudspeaker Connections con tact your McIntosh Dealer or McIn tosh Technical Support Output Terminals and How to Connect tosh Technical Support 9 Connect the MC302 power cord to an active AC 7 Connect the MC302 power cord to an active AC outlet outlet Spade Lug or Wire Connections 8 Connect the Loudspeaker hookup cables to the MC302 COM Negative Output Terminal and Positive Output Terminal indentified as 2Q ohms 4Q ohms or 8Q ohms connection to match the impedance of the Loudspeaker being careful to observe the correct polarities Insert the s
28. ure will result in a reduced life expectancy for the amplifier O com VOLTAGE AMP er Pe NEGATIVE CURRENT LIMITER NEGATIVE FEEDBACK Figure 15 The output signals of the amplifier circuit is coupled together in the unique McIntosh MC302 Output Autoformer It provides low distortion power transfer at frequencies from below 20Hz to well beyond 20 000Hz with optimum impedance points of two ohms four ohms and eight ohms The unequaled expertise of McIntosh in the design and manufactur ing of autoformers is legendary in the high fidelity industry The high efficiency circuit design of the MC302 contributes to low operating tem peratures More than 1400 square inches of heat sink area keep the MC302 operating safely with convection cooling No fans are needed Refer to figure 14 Autoformers All solid state power amplifier output circuits work best into what is called an optimum load This optimum load may vary Figure 14 It Technical Description con t The Autoformer creates an ideal match between the power amplifier output stage and the loudspeaker Refer to figure 16 There is abso lutely no perfor mance limitation with an Autoformer Its frequency re sponse exceeds that of the output circuit itself and extends well beyond the audible range Its distortion level is so low it is virtu ally impossible to measure In the rare event of a power amplifier output circuit failure the M
29. use cables of adequate size so there is little to no power loss in the cables The size is specified in Gauge Numbers or AWG American Wire Gauge The smaller the Gauge number the larger the wire Size Loudspeaker Cable Distance vs Wire Gauge Guide 7 62 meters 15 24 meters 30 48 meters or less or less orless C roms mawe ame mans sone ans mawo manc ment to the MC302 Power Amplifiers Bare wire cable ends cable ends refer to figures 2 3 amp 4 If the cable is stranded carefully twist the strands together Loudspeaker 25 feet 50 feet 100 feet Impedance 5 Prepare the Loudspeaker Hookup Cables for attach Carefully remove sufficient insulation from the as tightly as possible 0 5 inches 12 7mm Ga Figure 2 Notes 1 If desired the twisted ends can be tinned with solder to keep the strands together 2 The prepared bare wire cable ends may be inserted into spade lug connectors for use in outside the United States and Canada only 3 Banana plugs are for use in the United States and Canada only Figure 3 Figure 4 Banana Plugs are for use in the United States and Canada only 6 Attach the previously prepared bare wire cable ends into the banana plugs and secure the connections Refer to figure F 7 Rotate the top of the Output Termi nal Post clockwise until it is finger Figure F tight Refer to figure G Then using the McIntosh Wrench rotate the top of the Output Termi
30. we uane 3 Prepare the Loudspeaker Hookup Cable for attach ment to the MC302 Power Amplifier Bare wire cable ends Carefully remove sufficient insulation from the cable ends refer to figures 2 3 amp 4 If the cable is stranded carefully twist the strands together as tightly as possible 0 5 inches 12 7mm tr Figure 2 Figure 3 Figure 4 Notes 1 If desired the twisted ends can be tinned with solder to keep the strands together 2 The prepared bare wire cable ends may be inserted into spade lug connectors 3 Banana plugs are for use in the United States and Canada only Banana Plugs are for use in the United States and Canada only 4 Attach the previously prepared bare wire cable ends into the banana plugs and secure the connections Refer to figure F 5 Rotate the top of the Output Terminal Post clockwise until it is finger tight Refer to figure G Then using the McIntosh Wrench rotate the top of the Output Terminal one quarter of a turn 90 Do not over tighten Refer to w _ ai figure E a 6 Referring to figure H connect the Loudspeaker hookup cables with banana plugs into the hole at the top of the terminal to the MC302 COM Negative Output Termi nal and Positive Output Terminal indentified as 2Q ohms 4Q ohms or 8Q ohms connection to match the impedance of the Loudspeaker being Figure F Figure H careful to observe the correct polarities Note The illus
31. witch POWER CONTROL IN receives turn On Off signals from a McIntosh component POWER CONTROL OUT 1 and 2 send turn On Off signals to the next McIn tosh Component LEFT OUTPUT Connections for a 2 ohm 4 ohm or 8 ohm Loudspeaker Fuse holder refer to information on the rear panel of your MC302 to determine the correct fuse size and rating Output Terminals en sn A ae When connecting the Loudspeaker Hookup Cables to the MC452 Power Amplifier Output Terminals please follow the steps below 1 Rotate the top of the Output Terminal Post coun terclockwise until an opening appears Refer to figures A and B 2 Insert the Loudspeaker hookup cable into the Output Terminal Post opening or the cable spade lug around the center post of the Output Terminal Refer to figure C 3 Rotate the top of the Output Terminal Post clockwise until it is finger tight Refer to figure D 4 Place the supplied McIntosh Wrench over the top of the Out put Terminal and rotate it one quarter of a turn 90 to secure the Loudspeaker Cable Connec tion Do not over tighten Refer to figure E Figure A Figure B Figure C Figure E How to Connect Caution Do not connect the AC Power Cord to the MC302 Rear Panel until after the Loudspeaker Connections are made Failure to observe this could result in Electric Shock The connection instructions below together with the MC302 Connection Diagram located on th
32. y 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 607 724 0549 Copyright 2011 by McIntosh Laboratory Inc 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 Table of Contents DAL WS MISE UC MON ren 2 Thank You and Please Take a Moment 3 Technical Assistance and Customer Service 3 Table of Contents ea ee ee 3 General Information dis emtcetcnecectcnnczessoast odeccotedmeeneses 3 Connector and Cable Information 4 Fats eo 13 10 ei sessies ie ee isa eei 4 Performance Features seen 4 DESO ear E EE E AE EAE 5 Saa 1 AOSEBERIIEUEUUNEREEUFREUEEREBEREREEFEITERRFSURFERUERLFEUFEEUEFEER 6 Rear Panel Connections and Switch 7 Output Terminals and How to Connect 8 9 Output Terminals and How to Connect for Bi Amp PPIE eset HAIE SENEHRERRSUERE
Download Pdf Manuals
Related Search