McIntosh MC452 audio amplifier
Contents
1. 6 Remove Screws Remove Screws POWER CONTROL a O OLO IN OUTI OuT2 INPUT MODE F Be UNBALANGED o 2Q o e 120V 60Hz Annsy 8Q o o o 202 o CLASS 2 WIRING ER AMPLIFIE CE 8Q MN BAH 251 10 AMPS PUT 4 CLASS 2 WIRING 0 0 Y melntash Gy 2 o en QUAD ANGER K CAUTION MciN AVIS risque ve chocete l LJ Figure 1 This McIntosh MC452 Quad Balanced Power Ampli fier is designed for Loudspeakers with an impedance of 2 ohms 4 ohms or 8 ohms Connect a single Loud speaker only to the Right and Left Output Terminals When connecting Loudspeakers to the MC452 it is very important to use cables of adequate size so there 1s 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 7 62 meters 15 24 meters 30 48 meters or less or less or less 20nms 12AWG 10AWG 8AWG 40hms 14AWG 12AWG 10AWG 80hms 16AWG 14AWG 12AWG 6 Prepare the Loudspeaker Hookup Cable for attach ment to the MC452 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 together2. as tightly as possible 4 0 5 inches 12 7mm TH Figure 2 Loudspeaker Impedance 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 for use in outside the United States and Canada only 3 Banana plugs are for use in the United States and Canada only Output Terminals and How to Connect for Bi Amp Banana Plugs are for use in the United States and Canada only 7 Locate the Terminal Connections Covers from the inside of the MC452 shipping carton Insert the just prepared Loudspeaker hookup cables thru the cover openings one cover for each channel Refer to figure 5 Cover Qpening Cover Openings D GAN um E Ss O O tt AI ITE 9 3 3 3 El UE i c aga 3 3 a a a 8 2 INPUT MODE S S S i H IE mw Al UE LEI 1E ee o o iz eae Teed a 4 ARO pee BA rai y Ki un BE Er ME gt CLASS2WIRING i 2 WIRING MC452 QUAD BALANCED S A CAUTIONS POWER AMPLIFIER ce NG A A Cover Screws Cover Screws Figure 5 Inside USA and Canada 8 Attach the previously prepared bare wire cable ends into the banana
3. 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 Caution Do not connect the AC Power Cord to the MC452 Rear Panel until after the Loudspeaker Connections are made and the protective Termi nal Connections Covers are installed Failure to observe this could result in Electric Shock The connection instructions below together with the MC452 Connection Diagram located on the separate folded sheet Mc1A 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 MC452 POWER CONTROL IN 2 Connect XLR cables from the Balanced Output 1 L amp R ofan Audio Preamplifier or A V Control Center to the MC452 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 INPU
4. 2X SHIPPING CARTON BOTTOM 19 McIntosh Laboratory Inc 2 Chambers Street Binghamton NY 13903 www mcintoshlabs com The continuous improvement of its products is the policy of McIntosh Laboratory Incorporated who reserve the right to improve design without notice Printed in the U S A McIntosh Part No 04122601
5. The 450 watts power per channel high current output will drive any pair of high quality Loudspeakers The MC452 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 MC452 is a Power Amplifier with a capability of 450 watts per channel into 2 4 or 8 ohm speakers with less than 0 005 distortion The Power Amplifier Circuitry uses Thermal Trak Output Transistors for lower distortion and cool operation e Quad Balanced Circuitry The MC452 is fully balanced from inputs to outputs It consists of two matched power amplifiers operating in push pull with their outputs combined in a MclIn tosh Autoformer The Quad Balanced configuration cancels virtually all distortion 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 Sen
6. be a power REMOTE control connection between OFF ON the MC452 and the Audio Preamplifier or A V Con trol Center in order for the remote power turn on to Junction Figure 8 Meter Selection Rotate the meter mode switch to select the meter op eration mode you desire Refer to figures 9 and 10 Lights Off Meter lights are turned off and the meter will continue to indicate the power output Note When Power Con trol Input of the MC452 is con nected to a Audio Preamplifier or A V Control Center with Remote Meter Illumination Control the Meter Illumination will automati cally be remotely controlled On Off with the METER Switch set to the WATTS or HOLD position METER WATTS LIGHTS OFF HOLD Figure 9 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 1s 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 indication 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 Note The MC452 Power Output Meter indicates the actual power delivere
7. 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 semiconduc tor technology and incorporate a new design known as ThermalTrak Refer to figure 13 This allows for the instantaneous and accurate monitoring of the Power Tran sistor Temperature The MC452 Power Output Circuitry has a specially designed bias circuit to take full advantage of the ThermalTrakTM Power Transistors and thus precisely controls the power ampli fier operation over a wide range of music conditions with the benefits of lower distortion and cooler operation Precision metal film resistors and low dielectric absorption film capacitors are used in all critical circuit locations The output signals of the two balanced circuits are coupled together in the unique McIntosh MC452 Output Autoformer It provides low distortion power Figure 13 Technical Description 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 Suan Figure 14 UNBALANCED INPUT O UNBALANCED BALANCED INPUT Block Diagram of the Power Amplifier one channel shown expertise of McIntosh in the design and manufactur ing of autoformers is legendary in the high fidelity indus
8. plugs and secure the connections Refer to figure F Figure 9 Rotate the top of the Output Terminal paya Post clockwise until it is finger tight v 7 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 Figure G Refer to figure E 10 Referring to figure H connect the Loudspeaker hookup cables with ba nana plugs into the hole at the top of the terminal to the MC452 Negative Output Terminal and Positive Output Termi Figure H nal indentified as 2Q ohms 4Q ohms or 822 ohms connection to match the impedance of the Loudspeaker being careful to observe the correct polarities Note The illustration in figure 5 is connections for 82 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 11 Attach the Terminal Connections Covers to the MC452 Rear Panel with the previously removed Screws Refer to figure 5 12 Connect the MC452 power cord to an active AC outlet Spade Lug or Wire Connections 13 Locate the Terminal Connections C
9. McIntosh Laboratory Inc 2 Chambers Street Binghamton New York 13903 2699 Phone 607 723 3512 www mcintoshlabs com 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 I NTN Ad BW NY na 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 ka A AV S RISQUE DE CHOC ELECTRIQUE NE PAS OUVRIR NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED PERSONNEL thi
10. T MODE Switch in the UNBALANCED Position 3 Using a suitable tool remove the four screws from the MC452 Rear Panel and temporarily place them in a safe place Refer to figure 1 wow Remove Screws g Remove Screws asopo asopo INPUT MODE Hi E El em i i o 42 o 8Q f 120V 7 60Hz 15AH 250V 8Q o 4 RIGHT OUTPUT 4 F o 20 CLASS 2 WIRING 10 AMPS o o Mtintosh a MC452 QUAD BALANCED S M POW ER AMPLIFIER CE MeN ee J This McIntosh MC452 Quad Balanced Power Ampli fier is designed for Loudspeakers with an impedance of 2 ohms 4 ohms or 8 ohms Connect a single Loud speaker only to the Right and Left Output Terminals When connecting Loudspeakers to the MC452 it is very important to use cables of adequate size so there 1s little to no power loss in the cables The size is specified in Gauge Numbers or AWG American Wire Figure 1 Gauge The smaller the Gauge number the larger the wire size Loudspeaker 25 feet 50 feet 100 feet Inden 7 62 meters 15 24 meters 30 48 meters pedance Toma mawa me anne some awe awe roam 4 Prepare the Loudspeaker Hookup Cable for attach ment to the MC452 Power Amplifier Carefully remove sufficient insulation from the cable ends refer to figures 2 3 amp 4 If the cabl
11. charac teristics of McIn tosh Power Ampli fiers that make them world famous The MC452 also includes the unique patented McIntosh Power Guard circuit Power Guard eliminates the possibility of ever overdriving the amplifier into clip ping Refer to figures 19 20 and 21 An over driven amplifier can produce both audible and inaudible distortion levels exceeding 40 The audible distortion is unpleasant to hear but the inaudible ultrasonic distortion 1s also undesir able since it can damage valuable loudspeaker sys tem tweeters You will never experience the harsh and damaging distortion due to clipping The Power Guard circuit is a waveform compara tor monitoring both the input and output waveforms Under normal operating conditions there are no differences between the shape of these waveforms If Normal Operating Area Sentry Monitor Safety Area Output Transistor Failure Figure 18 Input Test Signal 14kHz amp 15kHz Figure 19 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 amplifier input reduces the input volume just enough to prevent any further increase in distortion The Power Guard circuit acts so fast that there are absolutely no audible side effects and the sonic purity of the music reproduction 1s perfectly pr
12. d to the loudspeakers by responding to the combination of current and voltage output Input Mode Switch The Input Mode Switch which is located on the Rear Panel of the MC452 allows selection of either the Bal INPUT MODE anced or Unbalanced Input a BALANCED Refer to figure 11 UNBALANCED Figure 11 Me Technical Description McIntosh Laboratory the company who introduced the world s first amplifier that could be called High Fidelity has done it again The McIntosh engineering staff has created a power amplifier without compro mise using the most advanced McIntosh circuit design concepts ABSEESREBALA BEBE EE EB n us MU AABAAAAAAM LEN MME Me nu u u u u u BY Hie Sh ACOTIT TT LO WT aoe GE BEB BBB ae PATAYAN ie lm fe EN i UTE RET LIE 1 PEPE BP gt 3345 oe Er E NAKALABAN pP EN wo AN 8 MC452 QUAD BALANCED POWER AMPLIFIER Precision Performance By MeIntosh Mcintosh Laboratory Inc Binghamton New York Made in U S A Figure 12 14 The MC452 has a continuous average power out put rating of 450 watts per channel and with a peak output current of 75 amperes making this one of the most advanced amplifiers available today The distor tion limits for the MC452 are no more than 0 005 at rated power output for all frequencies from 20Hz to 20 000Hz Typical perfor B nn UYUO6EEE AREA anal Bi LET EFE EE LILZITTITT
13. e as tightly as possible 12 7mm Loudspeaker Cable Distance vs Wire Gauge Guide or less or less or less 16AWG 14AWG 12AWG Bare wire cable ends is stranded carefully twist the strands together 0 5 inches 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 5 Locate the Terminal Connections Covers from the inside of the MC452 shipping carton Insert the Just prepared Loudspeaker hookup cables thru the cover openings one cover for each channel Refer to figure 5 OD FS a Cover Openings 5 Cover Openings 5 M M S our our O il Dom Ow sss WG DAMA JE TE CR TE 1E E ss JR TE TE CR TE TE NA TUT RIGHT OUTPUT 4 CLASS2WIRING a CLASS 2 WIRING 10 pal lelni oshi Gg ER Al MI PI EIF NG RISK OF ELECTRIC SHOCK ka nes AVIS RISQUEDE CHOCELECTRIQUE NEPASOUVAR Cover Screws Cover Screws Figure 5 Inside USA and Canada 6 Attach t
14. e pristine beauty of the MC452 will be retained for many years Dimensions Dimensions The following dimensions can assist in determining the best location for your MC452 Front View of the MC452 17 112 44 45cm WATTS 45 45 45 4 45 450 re O 2 POWER GUARD Na 40 30 20 10 ga o DECIBEI LEFT RIGHT POWER QUTPUT POWER METER REMOTE 8 7 8 9 7 16 22 54cm 23 97cm Rear View of the MC452 16 13 16 42 70cm ID O Ogio oo MD DI ID z a c seurmone 3 A F BU CEU LEL UEN LEN LE ses BU CEU ILEN EN MEN LB HE Zum S 11 314 29 85cm Eula 2 1 4 5 5 71cm Side View of the MC452 20 3 16 51 27cm a 17 15 16 45 55cm 7 N a CJ EEE 1 3 33 02cm 8 3 8 316 94 276m 0 48cm 2 3 16 5 55cm Me Installation The MC452 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 MC452 when it is custom installed as outlined below The four feet together with the
15. er 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 15 Attach the Terminal Connections Covers to the MC452 Rear Panel with the previously removed Screws Refer to figure 6 16 Connect the MC452 power cord to an active AC outlet Ll Ic Front Panel Displays and Controls Meter indicates the Standby Power Meter indicates the m SER ae LED indicates when the Left Sn tor LED indicates when the Right nn er a P Channel Amplifier POWER Channel Amplifier POWER P GUARD circuit activates GUARD circuit activates POWERIGUARD POWER QUTPUT METER POWER LIGHTS OFF HOLD Me ntos h OFF ON MC452 QUAD BALANCED POWER AMPLIFIER HU gl 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 MC452 automatically turn 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 POWER Note There must
16. er Connections are made and the protective Termi nal Connections Covers are installed Failure to observe this could result in Electric Shock The connection instructions below together with the MC452 Connection Diagram located on the separate folded sheet Mc1B is an example of a typical audio system Your system may vary from this however the actual components would be connected in a similar 10 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 MC452 POWER CONTROL IN Amplifier One 2 Connect a power control cable from Amplifier One Power Control OUTput 1 to the MC452 POWER CONTROL IN Amplifier Two 3 Connect XLR cables from the Balanced Output 1 L amp R of an Audio Preamplifier or A V Control Center to the MC452 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 4 Connect XLR cables from Amplifier One Audio Balanced OUTput LEFT and RIGHT to the MC452 Balanced INput RIGHT and LEFT Place the INPUT MODE Switch in the BALANCED Position 5 Using a suitable tool remove the four screws from the MC452 Rear Panel and temporarily place them in a safe place Be to er l O
17. eserved The MC452 Power Amplifier with Power Guard is not limited to just the rated power output but will actually produce distor tion free output well above its rated power due to the McIntosh philosophy of conservative design Without Power Guard Figure 20 With Power Guard Figure 21 Power Supply Circuits To compliment the design of the MC452 Power Am plifier Circuitry there is a high current high voltage power supply for both channels Refer to figures 22 and 25 The very large Power Transfomer can supply Technical Description con t Block Diagram POWER of the CONTROL Power Supply LOGIC LIGHTING CONTROL BACKUP POWER SUPPLY INRUSH AC Power O FUSE CURRENT LIMITER CONTROL MAIN RELAYS POWER SWITCH LOW VOLTAGE SUPPLY POWER TRANSFORMER MAIN SUPPLY Figure 22 over 20 amps of current Refer to figure 23 golf ball is for size comparsion Figure 23 It is enclosed in the legendary McIntosh Potted Enclo sures and weighs 301lbs The four super size main filter capacitors can store over 200 Joules of energy for both amplifier channels necessary for the wide dynamic range that Digital Audio demands Refer to figure 24 Din thi hie Figure 24 The power amplifier draws high current from the AC power line Therefore it is important that they plug directly into the wall outlet Also most owners desi
18. g kawa AA 18 Pack me AGNO een 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 MC452 3 The MC452 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 MC 452 In the event the MC452 over heats due to improper ventilation and or high ambient temperature the protection circuits will activate The Front Panel Power Guard LED will continuously indicate ON and the audio will be muted When the MC452 has returned to a safe operating temperature normal operation will
19. he design and manufacturing of Autoformers is legend ary in the high fidelity industry McIntosh engineers know how to do it right Figure 16 Me Technical Description con t Power Output Meter The McIntosh MC452 has large Output Watt Meter that responds 95 full scale to a single cycle tone burst at 2kHz Refer to figure 17 Voltage and cur rent outputs are electronically measured multi plied and fed to a special circuit that accelerates the pointer movement in the upward direction Refer to figure 25 on the next page When the pointer reaches its peak it pauses only long enough for the human eye to perceive its position 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 al lows fast upward movement of the pointer but greatly increases Hold Time at the peak of its travel The highest power output of the source material 1s thus recorded Figure 17 Protection Circuits The MC452 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 op eration of the amplifier under even the most extreme operating conditions The different types of protection 16 circuits incorpo rated in the MC452 insure a long and safe operating life This is just one of the many
20. he 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 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 figure E 8 Referring to figure H connect the Loudspeaker hookup cables with ba nana plugs into the hole at the top of the terminal to the MC452 Negative Output Terminal and Posi tive Output Terminal indentified as 202 ohms 40 ohms or 8Q ohms connection to match the impedance of the Loudspeaker being careful to observe the correct polarities Note The illustration in figure 5 is connections for 82 ohms Loudspeakers Figure H 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 9 Attach the Terminal Connections Covers to the MC452 Rear Panel with the previously removed Screws Refer to figure 5 10 Connect the MC452 power cord to an active AC outlet Spade Lug or Wire Connections 11 Locate the Term
21. inal Connections Covers from the inside of the MC452 shipping carton Insert the Just prepared Loudspeaker hookup cables thru the cover openings one cover for each channel Refer to figure 6 DI Cover Opening DI Cover Openings I 1 Ti oe e MO I I el LEN MEHI UE LEI LEN mu ey LEU El LEU WEI UE ee ee a AA F RIGHT OUTPUT CLASS 2 WIRING MeIntosh MC452 QUAD BALANCED POWER AMPLIFIER ce NG Over Screws Cover Screws Figure 6 Outside USA and Canada 12 Connect the Loudspeaker hookup cables to the MC452 Negative Output Terminal and Positive 13 14 Output Terminals and How to Connect 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 spade lug connector or prepared section of the cable end into the terminal side access hole and tighten the ter minal cap until the cable 1s firmly clamped into the terminals so the lugs or wire cannot slip out Refer to fgures 7 and 8 Figure 7 Figure 8 Note The illustration in figure 6 is connections for 82 ohms Loudspeakers If the Loudspeaker s impedance is in between the available connections use the nea
22. lation 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 000H7 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 s gnal Power Control Input 5 15VDC less than ImA Power Control Output 1 and 2 12V DC 50mA maximum total Output is delayed 0 2 seconds from turn On Specifications Power Requirements Field AC Voltage conversion of the MC452 is not possible The MC452 is factory configured for one of the following AC Voltages 100V 50 60Hz at 12 Amps 110V 50 60Hz at 11 Amps 120V 50 60Hz at 10 Amps 220V 50 60Hz at 6 Amps 230V 50 60Hz at 6 Amps 240V 50 60Hz at 6 Amps Standby less than 0 5 watt Note Refer to the rear panel of the MC452 for the cor rect voltage Overall Dimensions Width is 17 1 2 inches 44 45cm Height 1s 9 7 16 inches 23 97cm including feet Depth is 22 inches 55 88cm including the Front Panel Handles and Cables Weight 110 pounds 49 9 kg net 143 pounds 64 9 kg in ship ping carton Shipping Carton Dimensions Width is 29 1 2 inches 74 93cm Depth is 29 inches 73 66cm Height is 17 inches 43 18cm Packing Instructions Packing Instructions En In the event it 1s necessa
23. mounting screws should be retained for possible future use if the MCA452 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 MC452 Cool operation ensures the longest possible operating life for any electronic instrument Do not install the MC452 directly above a heat generating component such as a high powered amplifier If all the compo nents are installed in 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 2 1 2 inches 6 35 cm 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 MC432 is installed together with other McIn tosh Components check clearances on all components before proceeding 17 43 18cm Installation PAGG T NG POWER GUARD RIGHT MC452 Front Panel POWER QUTPUT 14 11 16 Cust
24. om Cabinet Cutout METER 37 30cm POWER REMOTE Cabinet Front Panel a 6 Cabinet 15 24cm Front Bu Panel ka Opening for Ventilation in Custom Cabinet MC452 Side View i Support AA Shelf 2 112 6 35cm MC452 Bottom View paaa 1 La AL in Custom Cabinet TUS 38cm 1 6 mn Cutout Opening for Ventilation Note Center the cutout Horizontally on the unit For purposes of clarity the above illustration is not drawn to scale 40 64cm Cutout Opening for Custom Mounting Chassis Spacers Rear Panel Connections and Switch Balanced OU Tputs LEFT and RIGHT Channels for an audio cable to the next Power Ampli fier Input INPUT MODE switch selects between Balanced or Unbalanced Inputs Unbalanced INput RIGHT Channel for an audio cable from a Preamplifier or A V Con trol Center audio output Unbalanced OU Tput RIGHT Channel for an audio cable to the next Power Amplifier Input INPUT MODE BALANCED UNBALANCED 120V v 60Hz 10 AMPS M 452 QUAD BALANCED POWER AMPLIFIER JEINTOSH LABORATORY INC BINGHAMTON NY 13903 MADE IN USA Balanced INputs LEFT and RIGHT Channels for audio cables from a Pre amplifier or A V Control Center audio output Unbalanced INput LEFT Channel f
25. or an au dio cable from a Preamplifier or A V Control Center audio output Unbalanced OUTput LEFT Channel for an audio cable to the next Power Amplifier Input 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 RIGHT OUTPUTS Connection for a 2 ohm Loudspeaker RIGHT OUTPUTS Fuse holder refer to information Connection for an 8 on the rear panel of your MC452 ohm Loudspeaker to determine the correct fuse size and rating RIGHT OUTPUTS Connect the MC452 power Connection for a 4 ohm Loudspeaker cord to a live AC outlet Refer to the rear panel to determine the correct voltage LEFT OUTPUTS Connection for an 8 ohm Loudspeaker LEFT OUTPUTS Connection for a 4 ohm Loudspeaker LEFT OUTPUTS Connections for a 2 ohm Loudspeaker Caution The Loudspeaker Negative Connections are above chassis ground Do not combine any connections together ground them or connect with another MC452 Me Output Terminals 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
26. overs from the inside of the MC452 shipping carton Insert the just prepared Loudspeaker hookup cables thru the cover openings one cover for each channel Refer to figure 6 14 Connect the Loudspeaker hookup cables to the MC452 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 spade lug connector or prepared section of the cable end into the terminal side access hole and tighten the ter ES ES DT gt ES O Cover Openings en Cover Openings O S O nm y a mm ME UE UE UE EEN gt CEN VEN WWE El WE LE eS SS ee RIGHT OUTPUT CLASS 2 WIRING o 82 E nn PUT 4 CLASS 2 WIRING 0 O Melntosh QUAD BALANCE S l R A PSr INOT OPEN o MC452 POWER AMPLIFIER ce Ng RY INC BI JE IN US 120V 60Hz 8Q iS 49 el 20 10 AMPS 15AH 250V over Screws Cover Screws Figure 6 Outside USA and Canada minal cap until the cable 1s 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 in figure 6 is connections for 82 ohms Loudspeakers If the Loudspeak
27. quipment 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 MC452 Quad Balanced Power Amplifier ranks you at the very top among discriminating music listeners You now have The Best The McIntosh dedication to Quality is assurance that you will receive many years of musical enjoyment from th s 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 any other brands that may be part of your sys
28. rd 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 EN 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 operate normally or has been dropped Do not expose this e
29. re one power switch for the whole audio system The MC452 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 Control Center is switched On a 45V signal operates the power relay in the MC452 The Figure 25 MC432 also has two remote Power Control Out Jacks The Power Control signal from these jacks are delayed by a fraction of a second so that the turn on power surge of the next power amplifier occurs at a later time This helps prevent power circuit overload that could trip circuit breakers or blow fuses a very impor tant feature in a high power Home Systems employing multiple MC452 Power Amplifiers Specifications Power Output Minimum sine wave continuous average power output per channel with both channels operating is 450 watts into 2 ohm load 450 watts into 4 ohm load 450 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 4 2 Volts Balanced 2 1 Volts Unbalanced Signal To Noise Ratio A Weighted 95dB Balanced 122dB below rated output 93dB Unbalanced 120dB below rated output 18 Intermodu
30. rest 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 Attach the Terminal Connections Covers to the MC452 Rear Panel with the previously removed Screws Refer to figure 6 Connect the MC452 power cord to an active AC outlet Me Output Terminals en sn nv co 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 D Figure E How to Connect for Bi Am Caution Do not connect the AC Power Cord to the MC452 Rear Panel until after the Loudspeak
31. 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 Nn 7 For additional information on the MC452 and other McIntosh Products please visit the McIntosh Web Site at www mcintosh labs com Connector and Cable Information XLR Connectors Below is the Pin configuration for the XLR Balanced Input Input Output Connectors on the MC452 Refer to the diagram for connection IN PIN 1 Shield Ground PIN 2 Input Output PIN 3 Input Output Power Control Connector The MC452 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 7 rent up to 50mA An additional Control connection is for controlling a Illumination the illumination of the MC452 Control Grolnd 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 stereo mini phone plugs on each end Introduction ee Now you can take advantage of traditional McIntosh standards of excellence in the MC452 Quad Balanced Power Amplifier
32. ry 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 1 1 2 NI BR BR me me me Part Number 034052 034051 034054 034186 034187 034136 034137 034188 034479 401212 104058 Description Shipping carton top Shipping carton bottom Foam Pad top and bottom Foam Pad front and rear Foam Pad sides Inner carton top Inner carton bottom Foam Pad inner carton Shipping skid 1 4 20x2 1 4 cap screw Flat washer INNER TY CARTON TOP FOAM PAD Mo and INNER CARTON SHIPPING 7 SKID IMPORTANT gt Read Above INNER CARTON BOTTOM pe Flat WASHER 4x 1 4 20 X 2 1 4 CAP SCREW 4x SHIPPING CARTON TOP FOAM PAD TOP INSIDE BOX FOAM PAD SIDE 2X FOAM PAD FRONT AND REAR
33. so r Pm GE S AAAAAAAAL Fiii TTS ITIT ELLE mance at mid frequencies is less than 0 002 The true dis tortion readings on the MC452 are so low it takes special measuring techniques to make accurate readings The MC452 can deliver the best possible performance from any type of high quality loudspeaker system Refer to figure 12 Creating an amplifier with this level of performance did not come easily Many months of design testing and measur ing were required Extensive controlled listening tests the ultimate form of measuring were made before the final design was accepted Design Philosophy The design philosophy incor porated in the MC452 involved several different techniques all based on sound scientific logic Every stage of voltage or current amplification must be as linear as possible prior to the use of negative feedback McIntosh engineers know how to properly design negative feedback cir cuits so they contribute to the extremely low distortion performance expected from a McIntosh amplifier The typical McIntosh owner would never accept the approximately 100 times higher distortion of many non feedback designs Double Balanced Push Pull design 1s used from input to output Bach half of the amplifier contains complimentary balanced circuitry The resulting Quad Balanced configuration cancels even order distortion Refer to figure 15 All transistors are selected to have nearly constant
34. tem 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 2010 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 IDSC ren 2 Thank You and Please Take a Moment 3 Technical Assistance and Customer Service 3 Table of Contents ee ee 3 General Information aa aNG 3 Connector and Cable Information 4 aa sessies ie RER EIN ee 4 Performance Features saaan daa 4 DESO AD 5 Saa 1 AOSEBERIIEUEUUNEREEUFREUEEREBEREREEFEITERRFSURFERUERLFEUFEEUEFEER 6 Rear Panel Connections and Switch 7 Output Terminals and How to Connect 8 9 Output Terimnals and How to Connect for Bi Amp AA 10 11 Front Panel Displays and Controls 12 How tO Operi ee engen 13 Technical Deserplion een 14 17 BS CC ALONA maaanina
35. try The high efficiency circuit design of the MC452 contributes to low operating temperatures More than 2800 square inches of heat sink area keep the MC452 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 op timum load may vary considerably from what a loudspeaker requires In the case of more than one loudspeaker connected in parallel the load to the power amplifier may drop to two ohms or even less A power amplifier connected to a load that is lower than Figure 15 being generated in optimum causes more output cur rent to flow which results in extra heat the power output stage This increase in temperature will result in a reduced life expectancy for the amplifier The special Balanced Winding Autoformer cre ates an ideal match between the power amplifier output stage and the loud speaker Refer to figure 16 There is absolutely no performance limita tion 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 virtually impos sible to measure In the rare event of a power amplifier out put circuit failure the McIntosh Autoformer provides absolute protection from possible damage to your valuable loudspeakers The unequaled expertise of McIntosh in t
36. try Monitor and Thermal Protection McIntosh Sentry Monitor power output stage protec tion circuits ensure the MC452 will have a long and ThermalTrakTM and ON Semiconductor are trademarks of Semi conductor Components Industries LLC trouble free operating life Built in Thermal Protection Circuits guard against overheating e Special Power Supply A very large Power Transformer and Large Capaci tors ensure stable noise free operation even though the power line varies e Illuminated Power Meters The Illuminated Power Output Watt Meters on the MC432 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 th
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