McIntosh MC-2000 User's Manual
Contents
1. How to Connect the MC2000 con t How to prepare cable ends A Carefully remove sufficient insulation from the cable ends to just fit within the binding post with no exposed wire accessible B If the cable is stranded carefully twist the strands together as tightly as possible Refer to figures 11 12 amp 13 ae 0 5 inches 12 7 cm Figure 11 Figure 12 Figure 13 Note If desired the twisted ends can be tinned with solder to keep the strands together or attach spade lug and or banana connector McIntosh C100 Preamplifier Ik Inlosh iw O18 0 0 O00 0 0 656 060 r ee Nay J MC2000 Front Panel Controls and Displays METER indicates the Left Channel Power Output METER indicates the Right Channel Power Output switchable to indicate bias readings of each pair of switchable to indicate bias readings of each pair of Left Channel Output Tubes Right Channel Output Tubes arate 41s 13 13 13 ua F ia 13 13 13 13 130 a r A h a j age POWER OUTPUT POWER OUTPUT METER Switch selects the display POWER Switch turns AC Power modes of the power output meters ON OFF or ON REMOTE modes Remote On Indicator 13 Melntosh How to Operate the MC2000 Power On To have the MC2000 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 sw2. 4 8 Amps 230 Volts 50 60Hz at 2 5 Amps Note Refer to the rear panel of the MC2000 for the correct voltage Dimensions 17 3 4 inches 45 1cm wide by 11 inches 27 9cm high Depth behind front panel is 18 3 4 inches 47 6 cm Handle clearance required in front of the mount ing panel is 1 5 8 inches 4 1 cm Finish Stainless Steel Chassis with Titanium Gold Super Mirror Finish Black Transformer Enclosures Black Base Glass Front Panel with gold plated Handles and Knobs Weight Amplifier 135 pounds 61 2 kg net 144 pounds 65 3 kg in shipping carton Accessories 18 pounds 8 2 kg in shipping carton Specifications Packing Instructions Packing Instructions In the event it is necessary to repack the MC2000 Amplifier for shipment the equipment must be packed exactly as shown below It is very important that the four metal feet are attached to the bottom of the equipment This will ensure the proper location of the MC2000 on the bottom foam pad The Vacuum Tubes and Tube Cover must be removed from the MC2000 Amplifier and packaged separately 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 De partment of McIntosh Laboratory Please see the Part List for the correct part numbers Power Amplifier C
3. Installation The installation of the MC2000 Tube Power Ampli fier in your system consists of three main steps 1 Unpacking the MC2000 along with accessories from their shipping cartons 2 Installation of the vacuum tubes and the protec tive tube cover 3 Finally the physical placement of the MC2000 in your system Note Two pairs of white gloves have been provided to prevent fingerprinting of the MC2000 during handling It is also recommended the gloves be used during the installation of the Vacuum Tubes into the MC2000 Unpacking the Amplifier and Accessories The MC2000 Amplifier and accessories have been packaged in specially designed shipping cartons to MC2000 Amplifier Figure 1 protect them from potential shipping damage and al low for easy removal from the cartons Please refer to the following steps Caution The MC2000 Amplifier weight is 135 pounds 61 2 kilograms It requires two or more persons to safely handle when moving the amplifier Unpacking the Amplifier 1 Remove the shipping carton banding strap s if any Note If these banding straps are metal use caution as the straps are under tension and may have sharp edges when cut 2 Lift off the top of the outer shipping carton 3 Lower the side flaps of the outer shipping car ton SCrews Inner Carton e b 4 Lift off the top of the inner shipping carton 5 Lower the side flaps of the inner shipping car ton 6 Li
4. the amplifier has been on for about 2 minutes make an initial adjustment as outlined below This should then be followed by a final adjustment after the MC2000 has been on for about 30 minutes 3 Facing the Left Side of the MC2000 press and hold in the momentary push button for V4 6 L Momentary and at the same time carefully adjust the BIAS Ghia Shy aa Potentiometer V4 6 L for a MC2000 Left Meter J indication centered between 13 and 1 3 Refer to ton figures 16 and 18 l Note The tip of a pen or other appropriate pointed BIAS ADJ nee tool can be used to push in the momentary push x button parein 4 In a similar manner adjust BIAS Potentiometer V5 7 L for the same meter indication centered between 13 and 1 3 5 Facing the Right Side of the MC2000 press and BIAS hold in the momentary push button for V5 7 R Potentionmeters and at the same time carefully adjust the BIAS Potentiometer V5 7 R for a MC2000 Right Meter indication centered between 13 and 1 3 Refer to figures 17 and 18 i Figurel6 Note The tip of a pen or other appropriate pointed Figure 17 Left Side of the MC2000 tool can be used to push in the momentary push Right Side of the MC2000 button 6 In a similar manner adjust BIAS Potentiometer V4 6 R for the same meter indication centered between 13 and 1 3 Momentary BIAS Potentionmeters Figure 18 15 Melntosh Technical Description In the late 1940 s F
5. 00m 1 2 5 10 20 50 100 200 Power in Watts Note These Performance Charts are examples of typical performance of the MC2000 Performance Charts 21 WMelntosh Specifications Power Output 130 watts into 8 4 or 2 ohm loads is the minimum sine wave continuous average power output per chan nel from 20Hz to 20 000Hz with both channels oper ating Total Harmonic Distortion 0 5 maximum harmonic distortion at any power level from 250 milliwatts to rated power per channel from 20Hz to 20 000Hz with both channels operat ing Intermodulation Distortion 0 5 maximum intermodulation distortion if instan taneous peak power output does not exceed twice the output rating per channel with both channels operat ing for any combination of frequencies from 20Hz to 20 000Hz Rated Power Band 20Hz to 20 000Hz Frequency Response at 1 watt 0 0 25dB from 20Hz to 20 000Hz 0 3dB from 10Hz to 100 000Hz Hum and Noise A Weighted 100dB below rated output Damping Factor Greater than 18 Output Load Impedance 2 4 or 8 ohms 22 Input Impedance 20K Ohms Unbalanced RCA Phono Jacks 40K Ohms Balanced XLR Connectors Input Sensitivity Switch Selectable 2 5 volts for rated output 1 2 volts for rated output 1 volt for 100 watts output Tubes Compliment 8 KT88 or 6550 Output Tubes 4 12AX7A Input Tubes 2 12AT7 Driver Tubes Power Requirement 100 Volts 50 60Hz at 5 8 Amps 120 Volts 50 60Hz at
6. MC2000 Tube Power Amplifier New Millennium Edition MC2000 Melntosh OWNER S MANUAL 50th Anniversary 1949 1999 Melntosh Frank H McIntosh Gordon J Gow For Fifty Years 1999 is the 50 year of business for McIntosh Laboratory of Binghamton New York It all started when Frank H McIntosh organized a small electronic en gineering consulting firm in the Washington DC area One of the many goals his firm ad dressed was the need for a high quality audio power amplifier No existing amplifier at that time could reproduce the entire audio range from 20Hz to 20 000Hz with low distortion Mr McIn tosh had a dream He wanted to create an audio power ampli fier that would far surpass the limited performance capa bilities of any power amplifier available in 1948 Mr McIntosh assembled a small team of talented and dedi cated people who shared his ideas and formed the original McIntosh Engineering Labora tory This beginning staff in cluded Gordon J Gow and Maurice L Painchaud both of whom would spend the rest of their productive lives working for the company that later be came McIntosh Laboratory Inc Initially both Mr Gow and Mr Painchaud were directly in volved in design engineering McIntosh s First Amplifier After months of research the dream had become reality The original McIntosh Power Am plifier the SOW 1 was created This amplifier was the first that could trul
7. S REMOTE LAMP Figure 21 19 WMelntosh Total Harmonic Distortion vs Frequency 8 Ohms 0 5 A 0 4 p 0 36 THD of 0 2 0 1 m a 20 50 100 200 500 1k 2k 5k 10k 20k Hz Hertz Frequency Response 1 Watt i 5 dB 10 Decibel 15 205 255 10 20 50 100 200 500 1k 2k 5k 10k 20k 50k 100k Hz Hertz Signal to Noise Ratio FFT Spectrum Analysis r ref full power dB Ap Decibel 20 50 100 200 500 1k 2k 5k 10k 20k Hz Hertz Note These Performance Charts are examples of typical performance of the MC2000 20 Total Harmonic Distortion vs Power Output 20Hz THD 300m 500m 1 2 5 10 20 50 100 200 Power in Watts Total Harmonic Distortion vs Power Output 1kHz 40 Ap THD Ao 300m 500m 1 2 5 10 20 50 100 200 Power in Watts Total Harmonic Distortion vs Power Output 20kHz THD Ao 300m 5
8. arton Part Number Quantity l RS S me WC 033096 034097 034098 034099 034100 034101 018626 Accessory Carton Quantity l l l l Part Number 034109 034108 034111 034112 Description Poly bag Bottom foam pad Foam ring Top foam pad Carton Top Carton Bottom Metal foot Description Tube carton gold with foam pads Inside carton white Outside carton kraft Foam pad set Note Refer to page 7 in this Owners 5 Manual for a view of the Accessory Carton CARTON TOP josh TOP pie FOAM PAD Wp FOAM RING 3 UNIT WITH 4 FEET ON BOTTOM COVER POLYBAG IS IMPORTANT Read Above BOTTOM FOAM PAD CARTON BOTTOM SEAL WITH PACKAGING TAPE USE BANDING S STRAPS AS SHOWN 23 WMelntosh McINTOSH LABORATORY INC 2 CHAMBERS STREET BINGHAMTON NEW YORK 13903 2699 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 Part No 040662
9. asses through the amplifier The meter pointer 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 is approximately 6dB per minute How to Set the Bias The BIAS ADJustments were made during the final testing of the MC2000 at the factory When you care to make BIAS ADJustments please follow the steps as listed Note Bias adjustments are not critical and are only necessary when the tubes have aged or been replaced Caution To prevent electrical shock make sure that the MC2000 AC POWER CORD IS NOT CONNECTED to the unit when inserting or removing tubes as there are hazardous voltages present at the pins of the tube sockets 1 Remove the BIAS ADJustment Protective Covers on each side of the MC2000 Refer to figure 15 Note Figure 15 shows the location of the BIAS ADJustments for the Right Channel which are located on the right side of the MC2000 The BIAS ADJustments for the Left Channel are located on the left side of the MC2000 in the same location Location of BIAS ADJustments Figure 15 2 Switch Power On to the MC2000 and wait for about 30 minutes before making any adjustments Note When the tube s are replaced set the corresponding bias control s to the fully counterclockwise position before turning on the How to Operate the MC2000 and Set the Bias MC2000 After
10. boratory is still producing ste reo equipment dedicated to the same basic philosophy of pro viding the finest possible repro duction of music The manage ment and financial assistance of the present company owner Clarion of Japan has made it possible for McIntosh to greatly expand and upgrade its design and manufacturing facilities in Binghamton New York The home product lineup includes many new and popular models for both Stereo and Home The ater applications A McIntosh Automotive Audio product line has been added that has achieved a reputation for perfor mance quality and reliability similar to the home products MC2000 Amplifier After his retirement Sidney Corderman was called back as interim President for a short pe riod and is currently a member of the Board of Directors Most recently he came out of retire ment again to design the McIn tosh MC2000 a 50 Anniver sary Edition vacuum tube Power Amplifier Pictured at the right are the C22 Preamplifier MR71 FM Tuner and the MCD7000 CD Player just three of the many McIntosh products designed by Sidney Corderman The MC2000 was Designed by Sidney A Corderman McIntosh MR71 FM Tuner McIntosh MCD7000 CD Player Melntosh Thank You Thank you for your decision to own this McIntosh MC2000 Tube Power Amplifier You now have The Best The McIntosh dedication to Quality 1s as surance that you will receive many years of musical enjoym
11. cesersacncdawexe 11 Front Panel Controls and Displays 0 13 How to Operate and Set the Bias eee 14 Technical Description 2h ceesmcenossescetecesaxecenctiees 16 Pertormance Cat ass ccesctincssicis niaaa 20 S015 8 C721 6 01 Meee eee eee eee cee ee ee meee nn 22 Packing Instruction cccccccssssssseeceeeeeeeeeeeeeeees 23 NOTE For additional connection information refer to the owner s manual s for any component s connected to the MC2000 Tube Power Amplifier Safety Instructions IMPORTANT SAFETY INSTRUCTIONS PLEASE READ THEM BEFORE OPERATING THIS EQUIPMENT WARNING SHOCK HAZARD h DO NOT OPEN The lightning flash with arrowhead within an equilat eral triangle is intended to alert the user to the pres ence of uninsulated dangerous voltage within the product s enclosure that may be of sufficient magni tude to constitute a risk of electric shock to persons AVIS RISQUE DE CHOC NE PAS OUVRIR The exclamation point within an equilateral triangle is intended to alert the user to the presence of im portant operating and maintenance servicing in structions in the literature accompanying the appli ance CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN NO USER SERVICEABLE PARTS INSIDE REFER SERVICING TO QUALIFIED DANGER D ELECTROCUTION NE PAS OUVRIR PERSONNEL To prevent the risk of electric shock do not remove cover or back No user servic
12. ch means that both windings are wound together two wires at the same time The secondary consists of five separate wind ings interspersed within the pri mary windings These five windings are connected in par allel Very tight coupling is ob tained which achieves wide bandwidth and flat frequency response The transformer core is four and one half square inches of grain oriented silicon steel This allows full power output down to 17 hertz Refer to figure 20 MC2000 Block Diagram of the Amplifier Section The output tubes operate with fixed bias which is adjust able and metered as explained later Because the output tubes are loaded in their cathodes they require a large grid drive signal of approximately 170 volts for full output This signal is provided by the 12AT7 driver stage The plates of the driver are resistance capacitance coupled to the output tubes Plate loading for the driver is boot strapped to the plate wind _ ing of the output transformer Boot strapping increases the effective plate load to the driver providing greater amplification than other wise possible A Darlington emitter follower stage is used at the grids of the output tubes to provide a rela tively low impedance to eliminate possible bias run away due to output tube grid current Inside of the MC2000 Technical Description UNBALANCED O LEFT INPUTS BALANCED UNITY INVERTING AMP Block Diagram of the Ampl
13. chassis adjacent to the input circuits Refer to figure 21 MC2000 Block Diagram of the Power Supply Power Transformers Each power transformer includes two tapped primary windings and three secondary windings Refer to fig ure 21 The primary can be connected for 100 120 or 230 volts by plug connections within the chassis A thermistor in series with the power line input to the transformer primary cushions the inrush surge cur rent The high voltage secondary winding feeds bridge rectifiers followed by capacitor input filters A Power MOS FET is used in place of a filter choke followed by a large output filter capacitor The volt age drop across the MOS FET is constant at all out put levels resulting in excellent power supply filter ing A medium voltage secondary winding feeds the negative bias voltage supply A low voltage second ary winding feeds the heaters of the output tubes driver tube and panel lamps This same winding also feeds regulated DC power supplies for the heaters of the 12AX7A input stages and the meter circuits Power Meters The power output of each amplifier channel is moni tored by separate meters The amplifier output signal is fed to a log converter amplifier then to a peak de tector a pulse stretcher then to a driver amplifier and the meter The meter displays the output power being delivered by that channel and is calibrated in watts The Meter Switch on the front panel allows the meter to be s
14. e of your loudspeakers being careful to observe the correct polarities Output impedance connections of 2 ohms 4 ohms and 8 ohms are provided Notes 1 If the impedance of your loudspeakers is different from the listed impedances use the nearest lower impedance connection 2 It is very important that loudspeaker cables of adequate size be used so that there will be no power loss or heating Cable size is specified in Gauge numbers or AWG American Wire Gauge The smaller the Gauge the larger the wire size If your loudspeaker cables are 50 feet 38 1m or less use 14 AWG wire size or larger If your loudspeaker cables are 100 feet 76 2m or less use 10 AWG wire size or larger 12 Spade lug or prepared wire connection Insert the spade lug connector or prepared sec tion of the cable end into the terminal side ac cess hole and tighten the terminal cap until the cable is firmly clamped into the terminal so the wires cannot slip out Refer to figures 8 9 amp 10 Note If the cables come without prepared ends proceed to How to prepare cable ends Hh Figure 8 Banana plug connection I Figure 9 Figure 10 Insert the banana plug into the hole at the top of the terminal and tighten the top portion of the terminal post to secure the banana plug in place
15. eable parts inside Refer servicing to qualified personnel General 1 Read all the safety and operating instructions contained in this owner s manual before operat ing this equipment 2 Retain this owner s manual for future reference about safety and operating instructions 3 Adhere to all warnings and operating instructions 4 Follow all operating and use instructions 5 Warning To reduce risk of fire or electrical shock do not expose this equipment to rain or moisture This unit is capable of producing high sound pressure levels Continued expo sure to high sound pressure levels can cause permanent hearing impairment or loss User caution is advised and ear protection is recom mended when playing at high volumes 6 Caution to prevent electrical shock do not use this polarized plug with an extension cord receptacle or other outlet unless the blades can be fully inserted to prevent blade exposure Attention pour pevenir les chocs elecriques pas utiliser cette fiche polarisee avec un prolongateur une prise de courant ou un autre sortie de courant sauf si les lames peuvent etre inserees afond ans en laisser aucune partie a decouvert 7 For added protection for this product during a lightning storm or when it is left unattended and unused for long periods of time unplug it from the wall outlet This will prevent damage to the product due to lightning or power line surges 8 Do not use attachments not r
16. ecommended in this owner s manual as they may cause hazards Installation 9 Locate the equipment for proper ventilation For example the equipment should not be placed on a bed sofa rug or similar surface that may block ventilation openings or placed in a built in in stallation such as a bookcase or cabinet that may impede the flow of air through the ventilation openings 10 Locate the equipment away from heat sources 11 12 13 such as radiators heat registers stoves or other appliance including amplifiers that produce heat Mount the equipment in a wall or cabinet only as described in this owner s manual Do not use this equipment near water for ex ample near a bathtub washbowl kitchen sink laundry tub in a wet basement or near a swim ming pool etc Do not place this product on an unstable cart stand tripod bracket or table The equipment may fall causing serious injury to a person and serious damage to the product Connection 14 15 16 17 Connect this equipment only to the type of AC power source as marked on the unit Route AC power cords so that they are not likely to be walked on or pinched by items placed upon or against them paying particular attention to cords at plugs convenience receptacles and the point where they exit from the instrument Do not defeat the inherent design features of the polarized plug Non polarized line cord adapters will defeat t
17. eed back is not desirable It 1s a scientific fact that many benefits result from properly applied global feedback Among them are a decrease in distortion a decrease in noise level flatter frequency response a decrease in rise time and an increase in output damping factor If not done properly amplifier instability can result and this has been considered One misconception 1s that the feedback signal is delayed from the amplifier input signal and therefore introduces time distortion This concept is wrong when a properly designed am plifier circuit 1s considered The phase delay intro duced by the entire MC2000 circuit is less than 2 mi croseconds which is certainly of no acoustic signifi cance MC2000 in Balanced Mode When the balanced amplifier input is selected a sec ond 12AX7A receives the balanced signal One sec tion of the tube 1s a cathode follower which passes the positive phase signal The other section inverts the negative phase signal The two outputs are com bined and feed to the input phase inverter stage de 18 scribed above Common mode rejection is greater than 60 dB at mid frequencies Slide switches at the rear of the chassis allow se lecting balanced or unbalanced inputs and to select input signal sensitivity of 1 2 volts or 2 5 volts for full power output At the 1 2 volt setting 1 volt of in put signal will produce 100 watts output The slide switches operate reed relays located at the front of the
18. ent from this unit Please take the time to read the information in this Owners Manual We want you to be as familiar as pos sible with all the features and functions of your new McIntosh MC2000 This will ensure that you receive all the performance benefits this equipment can offer you and that it will become a highly valued part of your home entertainment system Please Take A Moment OaM es The production number purchase date and McIntosh dealer name are important to you for possible insur ance claim or future service The spaces below have been provided for you to record that information Production Number Purchase Date Dealer Name Introduction The MC2000 was created by Sidney A Corderman McIntosh Co Founder to commemorate the 50 year of business for McIntosh Laboratory 1949 1999 and the Year 2000 Millennium The McIntosh MC2000 includes the latest innova tions in vacuum tube power amplifier technology based on 50 years of audio design expertise Two entirely separate power amplifiers and power supplies on a single chassis provide 130 watts per channel that is sonically transparent and absolutely accurate The McIntosh sound is The Sound of the Music Itself Technical Assistance If at any time you have questions about your MclIn tosh product contact your McIntosh dealer who is familiar with your McIntosh equipment and any other brands that may be part of your system If you or your dealer wish addit
19. fier or Control Center Audio Outputs LEFT UNBALANCED INPUT for audio cables from a Preampli fier or Control Center Audio Out puts LEFT OUTPUT connections for 2 4 or 8 ohm loudspeakers How to Connect the MC2000 ee How to Connect the MC2000 1 For Remote Power Control connect a power con trol cable from the Control Center or Preamplifier Power Control Out to the MC2000 Power Con trol In 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 2 Connect the MC2000 power cord to an active AC outlet Note Make sure that the MC2000 Front Panel Power Control is in the OFF position McIntosh C100 Controller Me ditto 7 f TINTHILLERA a m jeppa pmu up Se g 11 WMelntosh 3 Connect cables from the balanced outputs of a McIntosh Preamplifier or Control Center to the MC2000 Balanced Inputs Notes 1 An optional hookup is to use unbalanced cables from a preamplifier or control center to the MC2000 unbalanced inputs 2 The MC2000 may be connected in a Bridge Mono Mode for a total of 260 watts output contact your dealer or McIntosh for details 4 Connect the loudspeaker hookup cables to the output terminals which will accept bare cable ends spade lugs or banana plugs Attach cables to the terminals that match the impedanc
20. ft off the individual layers of foam packing material from the MC2000 Refer to figure 1 7 Put on the pair of white gloves this will pre vent fingerprinting of the MC2000 during handling 8 Remove the plastic shipping bag Unpacking the Accessories 1 Open the outer shipping carton 2 Remove the inner carton from the outer ship ping carton 3 Open the inner carton Refer to figure 2 4 Remove the accessories from the inner carton b gi y Tube Cover fastening Inner Carton Figure 2 Melntosh Installation of Tubes and Cover Your MC2000 has gone through an extensive series of performance tests during the manufacturing pro cess The actual tubes that were used to test and con firm the performance of this amplifier are included in the McIntosh MC2000 Tube Set Box refer to figure 3 Inside the tube set box is a plastic overlay that Figure 3 Note White gloves have been provided to prevent fingerprinting of the Vacuum Tubes during their installation into the MC2000 Power Output Tubes 1 Locate tube V4L KT88 or 6550 in the Tube Set Box Left side of the Box 2 Locate the matching tube socket on the MC2000 Chassis Left side of the Amplifier V4L KT88 6550 VIL 12AX7A Small Signal Tubes 1 Locate tube V1L 12AX7A in the Tube Set Box left side of the box Note There are two different types of small tubes 12AX7A and 12AT7 used in each channel The MC2000 will
21. he safety provided by the polarized AC plug If the plug should fail to fit contact your electrician to replace your obsolete outlet Do not defeat the safety purpose of the ground ing type plug Do not overload wall outlets extension cords or integral convenience receptacles as this can result in a risk of fire or electric shock WMelntosh Care of Equipment 18 Clean the instrument by using the supplied spe cial fabric cloth Unplug this equipment from the wall outlet and clean the front panel with a regu lar cloth moistened with a window cleaner Do not apply liquid or aerosol cleaners directly on the equipment 19 Do not permit objects of any kind to be pushed and or fall into the equipment through enclosure openings Never spill liquids into the equipment through enclosure openings 20 Unplug the power cord from the AC power out let when left unused for a long period of time Repair of Equipment 21 Unplug this equipment from the wall outlet and refer servicing to a qualified service personnel under the following conditions A The AC power cord or the plug has been damaged B Objects have fallen or liquid has been spilled into the equipment C The equipment has been exposed to rain or water D The equipment does not operate normally by following the operating instructions con tained within this owner s manual Adjust only those controls that are covered by the operating instructions as an improper ad
22. ifier Section UNITY INVERTING AMP BALANCED RIGHT INPUTS UNBALANCED O BALANCED UNBALANCED RELAY BALANCED UNBALANCED MODE SWITCH BALANCED UNBALANCED RELAY 1 2V 2 5V LEVEL RELAY INPUT LEVEL SWITCH 1 2V 2 5V LEVEL RELAY MUTE VOLTAGE N F B DRIVER OUTPUT MUTE BUFFER BUFFER AMP AMP O 8 Q OUTPUT O49 BIAS LEFT TRANS CONTROL OUTPUT FORMER O20 O COM PHASE DRIVER OUTPUT BUFFER BUFFER INVERTER AMP AMP L METER RECTIFIER a CIRCUIT METER HOLD SWITCH HOLD CIRCUIT RECTIFIER R METER PHASE DRIVER OUTPUT BUFFER BUFFER INVERTER AMP AMP O8o OUTPUT O 4 BIAS Q RIGHT TRANS CONTROL OUTPUT FORMER O2 Q O COM DRIVER BUFFER AMP VOLTAGE N F B Figure 20 OUTPUT BUFFER AMP 17 WMelntosh The driver stage is fed by the 12AX7A input phase inverter stage A resistance capacitance step network couples this stage to the driver This arrange ment controls low frequency phase shift The phase inverter uses no coupling capacitors so no low fre quency phase shift is introduced Emitter follower stages are used at the plates of the 12AX7A This iso lates the capacity loading of the driver input and in creases the bandwidth of the input inverter stage Proper Application of Feedback Global negative feedback is taken from the output transformer secondary to the cathode of the input stage There is a school of thought that global f
23. ional help concerning a sus pected problem you can receive technical assistance for all McIntosh products at McIntosh Laboratory Inc 2 Chambers Street Binghamton New York 13903 Phone 607 723 3512 Fax 607 723 3636 Customer Service SS 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 Repair Department at McIntosh Laboratory Inc 2 Chambers Street Binghamton New York 13903 Phone 607 723 3515 Fax 607 723 1917 Copyright 1999 by McIntosh Laboratory Inc Table of Contents A Brief History of McIntosh eeeeseeeeeees 2 The MC2000 was Designed by Sidney A Corderman cccccccsssssssssssseeeeeeeeeeees 3 Thank You eteceeo a cecgenate ected eraasctataaneacstossieatesadaoice shorts 4 Take a Moment oa secsaceswsevinnrsednestienesasiceseevesversncevenncts 4 Introduction senscie s 4 Technical Assistance cccecccceecccceeccceeesceeeeeseeees 4 Cu stomer SeryViCE eee ne irre en enee ei a 4 Tableol Gro oho 0 fen ne nen EN 4 Salety NHS DUC INO IS eset cateiceersncacunce ve ceeeetcestewezaasess sae 5 Performance Features ccceecccccsseeeccceeseeeceeneeee 6 ea O ae aianestakewete 7 Rear Panel Connections ccccccceeeccceseeseeeeeseeeee 10 How to CONN C Uavescecincececssstndcestassccctin
24. itch to the ON or OFF position as desired Note There must be a power control connection between the MC2000 and the McIntosh Control Center in order for the Remote Power Turn On to function Mode Switch Use the MODE Switch to select either the Balanced or Unbalanced inputs Refer to figure 14 Note The MODE Switch is located on the top panel rear of the MC2000 E Location of INPUT and MODE Switches Figure 14 14 Input Switch The INPUT Switch allows selection of two different input sensitivities Refer to figure 14 2 5V The recommended sensitivity when McIn tosh Preamplifiers or Control Centers are being used 1 2V An increased sensitivity for any signal source that is rated for less than 2 5V out put Note The INPUT Switch is located on the top panel at the rear of the MC2000 Meter Selection Rotate the Meter Mode Switch to select the Meter Operation Mode desired Lights Off Meter lights are turned off and the meters will indicate the power output Watts The meters indicate the power output and respond to all the musical informa tion being reproduced by the amplifier They indicate to an accuracy of at least 95 of the power output of either am plifier channel with only a single cycle of a 2000Hz tone burst Hold The meter pointer locks to the highest power peak in a sequence of peaks The meter is electronically held to this power level until another higher power peak p
25. justment of other controls may result in dam age and will often require extensive work by a qualified technician to restore the product to its normal operation E The equipment has been dropped or damaged in any way F The equipment exhibits a distinct change in Safety Instructions con t and Performance Features performance this indicates a need for service 22 Do not attempt to service beyond that described in the operating instructions All other service should be referred to qualified service personnel 23 When replacement parts are required be sure the service technician has used replacement parts specified by McIntosh or have the same character istics as the original part Unauthorized substitu tions may result in fire electric shock or other hazards 24 Upon completion of any service or repairs to this product ask the service technician to perform safety checks to determine that the product is in proper operating condition Performance Features Power Output The MC2000 is a Dual Mono design which consists of two entirely separate Mono 130 watt vacuum tube power amplifiers each with its own power supply Output impedance connections are provided for 2 4 and 8 ohm loudspeaker loads Patented Bifilar Wound Transformers and Output Circuit The power output sections utilize the famous MclIn tosh patented Unity Coupled Circuit with a Bifilar Wound Output Transformer for low distortion ex tended freq
26. not function if they are inserted into the wrong socket 2 Locate the matching tube socket on the MC2000 Chassis left side of the amplifier Shipping Screws Location identifies each tube and its specific socket location in the amplifier The MC2000 Chassis has nomenclature screened on it to specify both the circuit location and tube type for each channel refer to figure 4 It is ex tremely important to insert the tubes in the correct location Below is an example for installing one of the power output and small signal tubes into the MC2000 Tube Sockets for Left Channel Caution To prevent electrical shock make sure that the MC2000 AC POWER CORD IS NOT CONNECTED to the unit when inserting or removing tubes as there are hazardous voltages present at the pins of the tube sockets Figure 4 Figure 5 3 Orient the tube so that the key on the base of the tube is aligned with the corresponding key on the tube socket 4 Carefully insert the tube into the socket until the base of the tube is fully seated in the tube socket 5 Repeat the above the steps for the remaining 7 Power Output Tubes refer to figure 5 3 Orient the tube so that the area where no pins are located on the base of the tube is aligned with the corresponding area on the tube socket 4 Carefully insert the tube into the socket until the base of the tube is fully seated in the tube socket 5 Repeat the above steps for the remaining 5 Small Signal Tubes
27. r the warm air to escape at the top If all the components are installed in a single cabinet one or more quiet running ventilation fans can be a defi nite help in maintaining all the system components at their coolest possible operating temperatures Refer to figure 7 WMelntosh RIGHT CHANNEL BALANCED INPUT for audio cables from a Preamplifier or Control Center Audio Outputs RIGHT UNBALANCED INPUT for audio cables from a Preamplifier or Con trol Center Audio Outputs RIGHT OUTPUT connections for 2 4 or 8 ohm loudspeakers 10 POWER CONTROL IN and OUT receives a turn on signal and sends it to another McIntosh Component FUSE 2 HOLDER for the Right Chan nel refer to informa tion on the top rear panel of your MC2000 to deter mine the correct fuse size and rating INPUT SWITCH selects the desired amplifier sensitivity setting for both the Left and Right Channels MC2000 Rear Panel Connections MODE SWITCH selects Balanced or Unbalanced Inputs for both the Left and Right Channels z umbe E m re a mi y p ee ofthe mU et he m cd a a Connect the MC2000 power cord to an active AC outlet Refer to information on the back panel to deter mine the correct voltage FUSE 1 HOLDER for the Left Channel refer to information on the top rear panel of your MC2000 to determine the cor rect fuse size and rating LEFT BALANCED INPUT for audio cables from a Preampli
28. rank McIntosh and Gordon Gow invented and patented a new output circuit arrange ment for audio power amplifiers the McIntosh Unity Coupled Output Circuit Refer to figure 19 This cir cuit has two very impor tant features that differen tiate it from other de signs First the output tubes deliver their power from both their plates and their cathodes not from their plates alone as in conventional circuits Second the Unity Coupled Output Transformer having two bifi lar primary windings one for the plate and the other for the cathodes has one half the turns ratio equat ing to one fourth the impedance ratio of conven tional output transformers The resulting benefits are much lower distortion produced in the output stage and improved transformer design giving very close coupling primary to secondary for flat frequency re sponse and wide power bandwidth McIntosh Unity Coupled Output Circuit S Od Figure 19 MC2000 Application The MC2000 uses the Unity Coupled Output Circuit with KT 88 or 6550 output tubes in a push pull paral lel configuration These tube types are selected be cause of their excellent power and voltage ratings plus the favorable experience McIntosh has had with 16 them in the MC275 and other amplifier models The output tubes deliver signal to the output transformer through two primary windings one for the plates and the other for the cathodes These windings are wound bifilar whi
29. refer to figure 5 Installation con t After all the tubes have been inserted into the correct sockets the tube cover must to be installed before op erating the MC2000 Locate the tube cover and the two long fastening screws and perform the following steps Installing the Tube Cover 1 Orient the MC2000 so the Front Panel is facing you Tube Cover Fastening Screw Locations Figure 6 2 Remove the two shipping screws from the MC2000 Chassis with the supplied screw driver refer to figure 5 3 The Tube Cover has a wide opening along one side of it s longer dimension Orient this wide opening so that it is facing towards you 4 Insert the supplied long screws into each top side of the tube cover so they extend below the bottom edge 5 Carefully place the Tube Cover onto the MC2000 while at the same time aligning the screws with the openings on the MC2000 Chassis refer to figure 6 6 Using the supplied screwdriver secure the tube cover to the chassis do not over tighten the screws we sa a a Ee m Location and ventilation eee Adequate ventilation ex B tends the trouble free life of any electronic instru ment The suggested minimum space for mounting the MC2000 is 20 inches 50 8cm in width 22 inches 55 9cm depth and 17 inches 43 18cm in height Always allow air to flow through the venti lation holes on the bot Figure 7 tom of the amplifier and Cool Air a means fo
30. uency response and cool operating output tubes Balanced and Unbalanced Inputs Both Balanced and Unbalanced Inputs are included Balanced connections guard against induced noise and allow long cable runs without compromising sound quality Illuminated Power Meters Two accurate peak responding output meters con tinuously indicate the power delivered by each chan nel A Peak Hold Meter Mode indicates the maximum power reached over a given time span The meter 1l lumination can be turned off so as to not detract from the listening environment if desired Gold Plated Connectors Gold Plated Input jacks provide trouble free connec tions Gold Plated 200 ampere Output Binding posts accept spade lugs banana plugs or speaker cable up to 8 AWG diameter Ceramic Tube Sockets with Gold Contacts Ceramic tube sockets with gold plated contacts pro vide firm reliable connections that are not affected by atmospheric contamination Output tube sockets include Air Pipe cooling at their bases High Technology Power Supplies All voltages are electronically regulated or filtered for stable operation Twin regulated DC heater sup plies are provided for the Input tubes Glass Front Panel and Gold Plated Chassis The famous McIntosh Illuminated Glass Front Panel and the Stainless Steel Chassis with Titanium Gold Super Mirror Finish ensures the pristine beauty of the MC2000 will be retained for many years Installation
31. witched from the normal output mode to a Peak Hold mode which allows the meter to tempo rarily stay at the highest power reading during a given time with a gradual decay if power levels drop The meter switch also can turn off the meter lamps should that be desired The meter also serves as an indicator for setting the bias for the output tubes At the side of the chassis there are bias adjust controls and small push switches When a switch is pressed the amplifier is muted and the meter is connected to measure the cur rent flow in the output tubes The adjustment 1s not critical and should only be required when output tubes are replaced Power Control The Power Switch has three positions OFF RE MOTE and ON OFF and ON allow for manual op eration REMOTE allows power to be controlled by a command coming from a McIntosh Control Center or Preamplifier A red LED on the front panel lights to indicate that the REMOTE position has been se lected and the amplifier is in the standby mode Technical Description con t Block Diagram 12VAC of the Power Supply Section LEFT POWER Jay 12V MAIN 500V 150 AND petit DC DC DC SUPPLY 300V DC pies PAAR POWER LIMITER SELECTOR TRANSE ORMER 12VAC a a I ene 12V 2V MAIN 500V 150 AND POWER DC DC DC SUPPLY 300V DC SUPPLY INRUSH INPUT kia Poa ROWER TRANSFORMER LIMITER SELECTOR 2 O IN STANDBY CONTROL POWER POWER REMOTE TRANSFORMER 5V SUPPLY SWITCH CONTROL Sate JACK
32. y be described as High Fidelity with 50 watts output The Original McIntosh 50W1 Power Amplifier A Brief History of McIntosh from 20 cycles to 20 000 cycles with less than 1 distortion Now it was possible to repro duce music with a new degree of sonic accuracy that had never before been possible The suc cess of the company was se cure Additional new models were added and the company expanded into new facilities in Binghamton New York in 1951 At that time the company name was changed to the now familiar McIntosh Labora tory Inc Gordon Gow advanced to become Execu tive Vice Presi dent of Sales and after Frank MclIn tosh retired became Company President for the last twelve years of his life Maurice L Painchaud became Vice Presi dent of Operations and the Company Controller and was appointed President after the untimely death of Gordon Gow Maurice L Painchuad Sidney A Corderman Sidney with the famous McIntosh MC275 which he designed Sidney A Corderman In 1951 Sidney A Corderman joined the Company as Chief Engineer He was directly in volved with the designs of all the successful McIntosh prod ucts from that time on His elec tronic genius 1s unparalleled in the industry and the advanced performance of McIntosh prod ucts reflects his expertise McIn tosh audio electronics have be come the international standard for superior performance After 50 years McIntosh La
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