McIntosh MC2000 User manual

MC2000 Tube Power Amplifier
New Millennium Edition
MC2000 Tube Power Amplifier
New Millennium Edition
50th Anniversary 1 4 - 1
50th Anniversary 1 4 - 1 MC2000
OWNERS MANUAL

2
For Fifty Years
1999 is the 50th year of business
for McIntosh Laboratory of
Binghamton, New York. It a
started when Frank H. McIntosh
organized a sma e ectronic en-
gineering consu ting firm in the
Washington, DC area. One of
the many goa s his firm ad-
dressed was the need for a high
qua ity audio power
amp ifier. No existing
amp ifier at that time
cou d reproduce the
entire audio range
from 20Hz to
20,000Hz with ow
distortion. Mr. McIn-
tosh had a dream. He
wanted to create an
audio power amp i-
fier that wou d far
surpass the imited
performance capa-
bi ities of any power
amp ifier avai ab e in
1948.
Mr. McIntosh assemb ed a
sma team of ta ented and dedi-
cated peop e who shared his
ideas, and formed the origina
McIntosh Engineering Labora-
tory. This beginning staff in-
c uded Gordon J. Gow and
Maurice L. Painchaud, both of
whom wou d spend the rest of
their productive ives working
for the company that ater be-
came McIntosh Laboratory, Inc.
Initia y both Mr. Gow and Mr.
Painchaud were direct y in-
vo ved in design engineering.
McIntoshs First Amplifier
After months of research, the
dream had become rea ity. The
origina McIntosh Power Am-
p ifier, the 50W1, was created.
This amp ifier was the first that
cou d tru y be described as High
Fide ity, with 50 watts output
from 20 cyc es to 20,000 cyc es
with ess than 1% distortion.
Now it was possib e to repro-
duce music with a new degree
of sonic accuracy that had never
before been possib e. The suc-
cess of the company was se-
cure. Additiona new mode s
were added and the company
expanded into
new faci ities in
Binghamton,
New York in
1951. At that time
the company
name was
changed to the
now fami iar
McIntosh Labora-
tory, Inc. Gordon
Gow advanced to
become Execu-
tive Vice Presi-
dent of Sa es and
after Frank McIn-
tosh retired, became Company
President for the ast twe ve
years of his ife. Maurice L.
Painchaud became Vice Presi-
dent of Operations and the
Company Contro er, and was
appointed President after the
untime y death of Gordon Gow.
Frank H. McIntosh
Gordon J. Gow
Maurice L. Painchuad
Sidney A. Corderman
A Brief History of McIntosh
The riginal McIntosh
50W1 Power Amplifier

3
The MC2000 was Designed by Sidney A. Corderman
McIntosh C22 Preamplifier
McIntosh MR71 FM Tuner
McIntosh MCD7000 CD Player
Sidney A. Corderman
In 1951, Sidney A. Corderman
joined the Company as Chief
Engineer. He was direct y in-
vo ved with the designs of a
the successfu McIntosh prod-
ucts from that time on. His e ec-
tronic genius is unpara e ed in
the industry, and the advanced
performance of McIntosh prod-
ucts ref ects his expertise. McIn-
tosh audio e ectronics have be-
come the internationa standard
for superior performance.
After 50 years, McIntosh
Laboratory is sti producing ste-
reo equipment dedicated to the
same basic phi osophy of pro-
viding the finest possib e repro-
duction of music. The manage-
ment and financia assistance of
the present company owner,
C arion of Japan, has made it
possib e for McIntosh to great y
expand and upgrade its design
and manufacturing faci ities in
Binghamton, New York. The
home product ineup inc udes
many new and popu ar mode s
for both Stereo and Home The-
ater app ications. A McIntosh
Automotive Audio product ine
has been added that has
achieved a reputation for perfor-
mance, qua ity and re iabi ity
simi ar to the home products.
MC2000 Amplifier
After his retirement, Sidney
Corderman was ca ed back as
interim President for a short pe-
riod and is current y a member
of the Board of Directors. Most
recent y he came out of retire-
ment again to design the McIn-
tosh MC2000, a 50th Anniver-
sary Edition vacuum tube Power
Amp ifier.
Pictured at the right are the
C22 Preamp ifier, MR71 FM
Tuner and the MCD7000 CD
P ayer, just three of the many
McIntosh products designed by
Sidney Corderman.
Sidney with the famous McIntosh MC275 which he designed

4
Thank you for your decision to own this McIntosh
MC2000 Tube Power Amp ifier. You now have The
Best. The McIntosh dedication to Qua ity, is as-
surance that you wi receive many years of musica
enjoyment from this unit.
P ease take the time to read the information in this
Owners Manua . We want you to be as fami iar as pos-
sib e with a the features and functions of your new
McIntosh MC2000. This wi ensure that you receive
a the performance benefits this equipment can offer
you, and that it wi become a high y va ued part of
your home entertainment system.
Thank ou
A Brief History of McIntosh ................................... 2
The MC2000 was Designed by
Sidney A. Corderman ............................................. 3
Thank You ............................................................... 4
Take a Moment ....................................................... 4
Introduction ............................................................ 4
Technica Assistance ............................................... 4
Customer Service.................................................... 4
Tab e of Contents .................................................... 4
Safety Instructions .................................................. 5
Performance Features ............................................. 6
Insta ation .............................................................. 7
Rear Pane Connections ........................................ 10
How to Connect .................................................... 11
Front Pane Contro s and Disp ays ....................... 13
How to Operate and Set the Bias .......................... 14
Technica Description ........................................... 16
Performance Charts .............................................. 20
Specifications ....................................................... 22
Packing Instruction ............................................... 23
NOTE:
For additional connection information, refer to the
owners manual(s) for any component(s) connected to
the MC2000 Tube Power mplifier.
Table of ContentsTechnical Assistance
Customer Service
Copyright 1999 ã by McIntosh Laboratory, Inc.
If it is determined that your McIntosh product is in
need of repair, you can return it to your dea er. You
can a so 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: [phone]
Fax: [phone]
If at any time you have questions about your McIn-
tosh product, contact your McIntosh dea er who is
fami iar with your McIntosh equipment and any other
brands that may be part of your system. If you or
your dea er wish additiona he p concerning a sus-
pected prob em, you can receive technica assistance
for a McIntosh products at:
McIntosh Laboratory, Inc.
2 Chambers Street
Binghamton, New York 13903
Phone: [phone]
Fax: [phone]
Introduction
The MC2000 was created by Sidney A. Corderman,
McIntosh Co-Founder, to commemorate the 50th year
of business for McIntosh Laboratory (1949-1999),
and the Year 2000 Mi ennium.
The McIntosh MC2000 inc udes the atest innova-
tions in vacuum tube power amp ifier techno ogy based
on 50 years of audio design expertise. Two entire y
separate power amp ifiers and power supp ies on a
sing e chassis provide 130 watts per channe that is
sonica y transparent and abso ute y accurate. The
McIntosh sound is The Sound of the Music Itse f.
Please Take A Moment
The production number, purchase date and McIntosh
dea er name are important to you for possib e insur-
ance c aim or future service. The spaces be ow have
been provided for you to record that information:
Production Number:
Purchase Date:
Dealer Name:

5
IMPORTANT SAFETY
INSTRUCTIONS!
PLEASE READ THEM BEFORE
OPERATING THIS EQUIPMENT.
General:
1. Read a the safety and operating instructions
contained in this owners manua , before operat-
ing this equipment.
2. Retain this owners manua for future reference
about safety and operating instructions.
3. Adhere to a warnings and operating instructions.
4. Fo ow a operating and use instructions.
5. arning: 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
ightning storm, or when it is eft unattended and
unused for ong periods of time, unp ug it from
the wa out et. This wi prevent damage to the
product due to ightning or power ine surges.
8. Do not use attachments not recommended in this
owners manua as they may cause hazards.
Installation:
9. Locate the equipment for proper venti ation. For
examp e, the equipment shou d not be p aced on
a bed, sofa, rug, or simi ar surface that may b ock
venti ation openings; or, p aced in a bui t-in in-
sta ation, such as a bookcase or cabinet, that may
impede the f ow of air through the venti ation
openings.
10. Locate the equipment away from heat sources
such as radiators, heat registers, stoves, or other
app iance (inc uding amp ifiers) that produce
heat.
11. Mount the equipment in a wa or cabinet on y as
described in this owners manua .
12. Do not use this equipment near water; for ex-
amp e, near a bathtub, washbow , kitchen sink,
aundry tub, in a wet basement or near a swim-
ming poo , etc.
13. Do not p ace this product on an unstab e cart,
stand, tripod, bracket, or tab e. The equipment
may fa , causing serious injury to a person, and
serious damage to the product.
Connection:
14. Connect this equipment on y to the type of AC
power source as marked on the unit.
15. Route AC power cords so that they are not ike y
to be wa ked on or pinched by items p aced upon
or against them, paying particu ar attention to
cords at p ugs, convenience receptac es, and the
point where they exit from the instrument.
16. Do not defeat the inherent design features of the
po arized p ug. Non-po arized ine cord adapters
wi defeat the safety provided by the po arized
AC p ug. If the p ug shou d fai to fit, contact
your e ectrician to rep ace your obso ete out et.
Do not defeat the safety purpose of the ground-
ing-type p ug.
17. Do not over oad wa out ets, extension cords or
integra convenience receptac es as this can resu t
in a risk of fire or e ectric shock.
Safety Instructions
WARNING SHOCK HAZARD -
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 e clamation 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.
NO USER-SERVICEABLE
PARTS INSIDE. REFER
SERVICING TO QUALIFIED
PERSONNEL
To prevent the risk of electric shock, do not remove
cover (or back). No user serviceable parts inside.
Refer servicing to qualified personnel.

6
Care of Equipment:
18. C ean the instrument by using the supp ied spe-
cia fabric c oth. Unp ug this equipment from the
wa out et and c ean the front pane with a regu-
ar c oth moistened with a window c eaner. Do
not app y iquid or aeroso c eaners direct y on
the equipment.
19. Do not permit objects of any kind to be pushed
and/or fa into the equipment through enc osure
openings. Never spi iquids into the equipment
through enc osure openings.
20. Unp ug the power cord from the AC power out-
et when eft unused for a ong period of time.
Repair of Equipment:
21. Unp ug this equipment from the wa out et and
refer servicing to a qua ified service personne
under the fo owing conditions:
A. The AC power cord or the p ug has been
damaged.
B. Objects have fa en, or iquid has been spi ed
into the equipment.
C. The equipment has been exposed to rain or
water.
D. The equipment does not operate norma y by
fo owing the operating instructions con-
tained within this owners manua . Adjust
on y those contro s that are covered by the
operating instructions, as an improper ad-
justment of other contro s may resu t in dam-
age and wi often require extensive work by
a qua ified technician to restore the product
to its norma operation.
E. The equipment has been dropped or damaged
in any way.
F. The equipment exhibits a distinct change in
performance - this indicates a need for service.
22. Do not attempt to service beyond that described in
the operating instructions. A other service shou d
be referred to qua ified service personne .
23. When rep acement parts are required, be sure the
service technician has used rep acement parts
specified by McIntosh or have the same character-
istics as the origina part. Unauthorized substitu-
tions may resu t in fire, e ectric shock, or other
hazards.
24. Upon comp etion 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.
·Power Output
The MC2000 is a Dua Mono design which consists
of two entire y separate Mono, 130 watt vacuum tube
power amp ifiers, each with its own power supp y.
Output impedance connections are provided for 2, 4
and 8 ohm oudspeaker oads.
·Patented Bifilar ound Transformers and
Output Circuit
The power output sections uti ize the famous McIn-
tosh patented Unity Coup ed Circuit with a Bifi ar
Wound Output Transformer for ow distortion, ex-
tended frequency response and coo operating output
tubes.
·Balanced and Unbalanced Inputs
Both Ba anced and Unba anced Inputs are inc uded.
Performance Features
Ba anced connections guard against induced noise
and a ow ong cab e runs without compromising
sound qua ity.
·Illuminated Power Meters
Two accurate, peak responding output meters con-
tinuous y indicate the power de ivered by each chan-
ne . A Peak Ho d Meter Mode indicates the maximum
power reached over a given time span. The meter i -
umination can be turned off so as to not detract from
the istening environment, if desired.
·Gold Plated Connectors
Go d P ated Input jacks provide troub e free connec-
tions. Go d P ated 200 ampere Output Binding posts
accept spade ugs, banana p ugs or speaker cab e up
to #8 AWG diameter.
·Ceramic Tube Sockets with Gold Contacts
Ceramic tube sockets with go d p ated contacts pro-
vide firm, re iab e connections that are not affected
by atmospheric contamination. Output tube sockets
inc ude Air-Pipe coo ing at their bases.
·High Technology Power Supplies
A vo tages are e ectronica y regu ated or fi tered
for stab e operation. Twin regu ated DC heater sup-
p ies are provided for the Input tubes.
·Glass Front Panel and Gold Plated Chassis
The famous McIntosh I uminated G ass Front Pane
and the Stain ess Stee Chassis with Titanium Go d
Super Mirror Finish ensures the pristine beauty of the
MC2000 wi be retained for many years.
Safety Instructions cont, and Performance Features

7
Installation
The insta ation of the MC2000 Tube Power Amp i-
fier in your system consists of three main steps:
1. Unpacking the MC2000 a ong with accessories
from their shipping cartons.
2. Insta ation of the vacuum tubes and the protec-
tive tube cover.
3. Fina y, the physica p acement 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 Amp ifier and accessories have been
packaged in specia y designed shipping cartons, to
Installation
protect them from potentia shipping damage and a -
ow for easy remova from the cartons. P ease refer to
the fo owing 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 Amp ifier:
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 f aps of the outer shipping car-
ton.
4. Lift off the top of the inner shipping carton.
5. Lower the side f aps of the inner shipping car-
ton.
6. Lift off the individua ayers of foam packing
materia from the MC2000. Refer to figure 1.
7. Put on the pair of white g oves (this wi pre-
vent fingerprinting of the MC2000 during
hand ing).
8. Remove the p astic 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.
Figure 1
Foam Layers
Inner Carton
Plastic Bag
MC2000
Amplifier
Figure 2
Tube Cover
Tube Cover
fastening
screws Tube Bo
Screwdriver
Power Cord
Inner Carton
Adjustment tool

8
Installation of Tubes and Cover
Your MC2000 has gone through an extensive series
of performance tests during the manufacturing pro-
cess. The actua tubes that were used to test and con-
firm the performance of this amp ifier are inc uded in
the McIntosh MC2000 Tube Set Box, refer to figure
3. Inside the tube set box is a p astic over ay that
identifies each tube and its specific socket ocation in
the amp ifier. The MC2000 Chassis has nomenc ature
screened on it to specify both the circuit ocation and
tube type for each channe , refer to figure 4. It is ex-
treme y important to insert the tubes in the correct
ocation. Be ow is an examp e for insta ing one of
the power output and sma signa tubes into the
MC2000 Tube Sockets for Left Channe :
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.
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 Amp ifier).
3. Orient the tube so that the key on the base of the
tube is a igned with the corresponding key on
the tube socket.
4. Carefu y insert the tube into the socket unti the
base of the tube is fu y seated in the tube
socket.
5. Repeat the above the steps for the remaining 7
Power Output Tubes, refer to figure 5.
Sma Signa Tubes:
1. Locate tube V1L (12AX7A) in the Tube Set
Box ( eft side of the box).
Note: There are two different types of small tubes
(12 X7 and 12 T7) used in each channel. The
MC2000 will not function if they are inserted into
the wrong socket.
2. Locate the matching tube socket on the
MC2000 Chassis ( eft side of the amp ifier).
3. Orient the tube so that the area where no pins
are ocated on the base of the tube is a igned
with the corresponding area on the tube socket.
4. Carefu y insert the tube into the socket unti the
base of the tube is fu y seated in the tube
socket.
5. Repeat the above steps for the remaining 5
Sma Signa Tubes, refer to figure 5.
Figure 3
Plastic Overlay
Left Channel Tubes
Right Channel Tubes
Figure 4
V4L (KT88/6550)
V1L (12AX7A)
Figure 5
Shipping Screws Location

9
Installation, cont
Figure 6
Tube Cover Fastening Screw Locations
Tube Cover Wide Side Opening
After a the tubes have been inserted into the correct
sockets, the tube cover must to be insta ed before op-
erating the MC2000. Locate the tube cover and the
two ong fastening screws and perform the fo owing
steps:
Insta ing the Tube Cover:
1. Orient the MC2000 so the Front Pane is facing
you.
2. Remove the two shipping screws from the
MC2000 Chassis with the supp ied screw-
driver, refer to figure 5.
3. The Tube Cover has a wide opening a ong one
side of its onger dimension. Orient this wide
opening so that it is facing towards you.
4. Insert the supp ied ong screws into each top
side of the tube cover so they extend be ow the
bottom edge.
5. Carefu y p ace the Tube Cover onto the
MC2000 whi e at the same time a igning the
screws with the openings on the MC2000
Chassis, refer to figure 6.
6. Using the supp ied
screwdriver secure
the tube cover to the
chassis, do not over
tighten the screws.
Location and
ventilation
Adequate venti ation ex-
tends the troub e free ife
of any e ectronic 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. A ways a ow air
to f ow through the venti-
ation ho es on the bot-
tom of the amp ifier and
a means for the warm air
to escape at the top. If a
the components are insta ed in a sing e cabinet, one
or more quiet running venti ation fans can be a defi-
nite he p in maintaining a the system components at
their coo est possib e operating temperatures. Refer to
figure 7.
Figure 7
Cool Air
Warm Air

10
MC2000 Rear Panel Connections
LEFT BALANCED INPUT for
audio cables from a Preampli-
fier or Control Center Audio
utputs
RIGHT CHANNEL BALANCED
INPUT for audio cables from a
Preamplifier or Control Center
Audio utputs
RIGHT UNBALANCED
INPUT for audio cables
from a Preamplifier or Con-
trol Center Audio utputs
RIGHT UTPUT connections
for 2, 4 or 8 ohm loudspeakers
M DE SWITCH
selects Balanced
or Unbalanced
Inputs for both the
Left and Right
Channels
INPUT SWITCH
selects the desired
amplifier sensitivity
setting for both the
Left and Right
Channels
FUSE 1 H LDER
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 UTPUT connections
for 2, 4 or 8 ohm loudspeakers
LEFT UNBALANCED INPUT
for audio cables from a Preampli-
fier or Control Center Audio ut-
puts
FUSE 2 H LDER
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
Connect the
MC2000 power
cord to an active
AC outlet. Refer to
information on the
back panel to deter-
mine the correct
voltage
P WER C NTR L IN and UT
receives a turn-on signal and sends it
to another McIntosh Component

11
McIntosh C100 Controller
1. For Remote Power Contro , connect a power con-
tro cab e from the Contro Center or Preamp ifier
Power Contro Out to the MC2000 Power Con-
tro 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
out et.
Note: Make sure that the MC2000 Front Panel Power
Control is in the OFF position.
How to Connect the MC2000
How to Connect the MC2000
To AC utlet

12
McIntosh C100 Preamplifier
Spade ug or prepared wire connection:
Insert the spade ug connector or prepared sec-
tion of the cab e end into the termina side ac-
cess ho e, and tighten the termina cap unti the
cab e is firm y c amped into the termina so the
wires cannot s ip out. Refer to figures 8, 9 & 10.
Note: If the cables come without prepared ends,
proceed to How to prepare cable ends.
Banana p ug connection:
Insert the banana p ug into the ho e at the top of
the termina and tighten the top portion of the
termina post to secure the banana p ug in p ace.
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3. Connect cab es from the ba anced outputs of a
McIntosh Preamp ifier or Contro Center to the
MC2000 Ba anced Inputs.
Notes: 1. n 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 oudspeaker hookup cab es to the
output termina s, which wi accept bare cab e
ends, spade ugs, or banana p ugs. Attach cab es
to the termina s that match the impedance of your
oudspeakers, being carefu to observe the correct
po arities. 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 WG,
( merican Wire Gauge). The smaller the
Gauge, the larger the wire size:
If your loudspeaker cables are 50
feet (38.1m) or less, use 14
( WG) wire size or larger.
If your loudspeaker cables are
100 feet (76.2m) or less, use 10
( WG) wire size or larger.
How to Connect the MC2000, cont
How to prepare cab e ends:
A. Carefu y remove sufficient insu ation from
the cab e ends to just fit within the binding
post with no exposed wire accessib e.
B. If the cab e is stranded, carefu y twist the
strands together as tight y as possib e. Refer
to figures 11, 12 & 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.

13
MC2000 Front Panel Controls and Displays
P WER Switch turns AC Power,
N/ FF, or N/REM TE modes
METER indicates the Left Channel Power utput,
switchable to indicate bias readings of each pair of
Left Channel utput Tubes
METER indicates the Right Channel Power utput,
switchable to indicate bias readings of each pair of
Right Channel utput Tubes
Remote n Indicator
METER Switch selects the display
modes of the power output meters

14
Power On
To have the MC2000 automatica y turn On or Off
when a Contro Center turns On or Off, rotate the
POWER Switch to the REMOTE position. For
manua operation, rotate the power switch 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 se ect either the Ba anced
or Unba anced inputs. Refer to figure 14.
Note: The MODE Switch is located on the top panel
(rear) of the MC2000.
How to Operate the MC2000
Input Switch
The INPUT Switch a ows se ection of two different
input sensitivities. Refer to figure 14.
2.5V The recommended sensitivity when McIn-
tosh Preamp ifiers or Contro Centers are
being used.
1.2V  An increased sensitivity for any signa
source that is rated for ess 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 se ect the Meter
Operation Mode desired.
Lights Off  Meter ights are turned off and the
meters wi indicate the power output.
Watts  The meters indicate the power output
and respond to a the musica informa-
tion being reproduced by the amp ifier.
They indicate to an accuracy of at east
95% of the power output of either am-
p ifier channe with on y a sing e cyc e
of a 2000Hz tone burst.
Ho d  The meter pointer ocks to the highest
power peak in a sequence of peaks.
The meter is e ectronica y he d to this
power eve unti another higher power
peak passes through the amp ifier. The
meter pointer wi then rise to the
newer higher indication. If no further
power peaks are reached, the meter
pointer wi very s ow y return to its
rest position or ower power eve . The
decay rate is approximate y 6dB per
minute.
Location of INPUT and MODE Switches
Figure 14
Location of BIAS ADJustments
Figure 15
How to Set the Bias
The BIAS ADJustments were made during the fina
testing of the MC2000 at the factory. When you care
to make BIAS ADJustments, p ease fo ow the steps
as isted:
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 BI S
DJustments for the Right Channel, which are
located on the right side of the MC2000. The
BI S DJustments for the Left Channel are
located on the left side of the MC2000, in the
same location.
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

15
MC2000. fter 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
ho d in the momentary push-button for V4+6 L,
and at the same time carefu y adjust the BIAS
Potentiometer V4+6 L for a MC2000 Left Meter
indication centered between .13 and 1.3. Refer to
figures 16 and 18.
Note: The tip of a pen, or other appropriate pointed
tool, can be used to push in the momentary push-
button.
4. In a simi ar 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
ho d in the momentary push-button for V5+7 R,
and at the same time carefu y 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.
Note: The tip of a pen, or other appropriate pointed
tool, can be used to push in the momentary push-
button.
6. In a simi ar manner, adjust BIAS Potentiometer
V4+6 R for the same meter indication centered
between .13 and 1.3.
How to Operate the MC2000 and Set the Bias
Figure 18
Figure16
Left Side of the MC2000
BIAS
Potentionmeters
Momentary
Push-buttons
Figure 17
Right Side of the MC2000
BIAS
Potentionmeters
Momentary

16
Technical Description
In the ate 1940s Frank McIntosh and Gordon Gow
invented and patented a new output circuit arrange-
ment for audio power amp ifiers, the McIntosh Unity
Coup ed 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 de iver
their power
from both
their p ates
and their
cathodes, not
from their
p ates a one as in conventiona circuits. Second, the
Unity Coup ed Output Transformer, having two bifi-
ar primary windings (one for the p ate and the other
for the cathodes), has one ha f the turns ratio (equat-
ing to one fourth the impedance ratio) of conven-
tiona output transformers. The resu ting benefits are
much ower distortion produced in the output stage
and improved transformer design giving very c ose
coup ing primary to secondary for f at frequency re-
sponse and wide power bandwidth.
MC2000 Application
The MC2000 uses the Unity Coup ed Output Circuit
with KT-88 or 6550 output tubes in a push-pu para -
e configuration. These tube types are se ected be-
cause of their exce ent power and vo tage ratings
p us the favorab e experience McIntosh has had with
them in the MC275 and other amp ifier mode s. The
output tubes de iver signa to the output transformer
through two primary windings, one for the p ates and
the other for the cathodes. These windings are wound
bifi ar, which 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-
a e . Very tight coup ing is ob-
tained, which achieves wide
bandwidth and f at frequency
response. The transformer core
is four and one ha f square
inches of grain oriented si icon
stee . This a ows fu power
output down to 17 hertz.
Refer to figure 20, MC2000
B ock Diagram of the Amp ifier
Section.
The output tubes operate
with fixed bias, which is adjust-
ab e and metered as exp ained
ater. Because the output tubes
are oaded in their cathodes,
they require a arge grid drive
signa of approximate y 170
vo ts for fu output. This signa
is provided by the 12AT7 driver
stage. The p ates of the driver
are resistance-capacitance
coup ed to the output tubes.
P ate oading for the driver is
boot strapped to the p ate wind-
ing of the output transformer.
Boot strapping increases the effective p ate oad to
the driver providing greater amp ification than other-
wise possib e. A Dar ington emitter fo ower stage is
used at the grids of the output tubes to provide a re a-
tive y ow impedance to e iminate possib e bias run-
away due to output tube grid current.
Figure 19
McIntosh Unity Coupled utput Circuit
Inside of the MC2000

17
Technical Description
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Figure 20
Block Diagram
of t e
Amplifier Section

18
The driver stage is fed by the 12AX7A input/
phase inverter stage. A resistance-capacitance step
network coup es this stage to the driver. This arrange-
ment contro s ow frequency phase shift. The phase
inverter uses no coup ing capacitors so no ow fre-
quency phase shift is introduced. Emitter fo ower
stages are used at the p ates of the 12AX7A. This iso-
ates the capacity oading of the driver input and in-
creases the bandwidth of the input/inverter stage.
Proper Application of Feedback
G oba negative feedback is taken from the output
transformer secondary to the cathode of the input
stage. There is a schoo of thought that g oba feed-
back is not desirab e. It is a scientific fact that many
benefits resu t from proper y app ied g oba feedback.
Among them are a decrease in distortion, a decrease
in noise eve , f atter frequency response, a decrease
in rise time, and an increase in output damping factor.
If not done proper y amp ifier instabi ity can resu t
and this has been considered. One misconception is
that the feedback signa is de ayed from the amp ifier
input signa and therefore introduces time distortion.
This concept is wrong when a proper y designed am-
p ifier circuit is considered. The phase de ay intro-
duced by the entire MC2000 circuit is ess than 2 mi-
croseconds, which is certain y of no acoustic signifi-
cance.
MC2000 in Balanced Mode
When the ba anced amp ifier input is se ected, a sec-
ond 12AX7A receives the ba anced signa . One sec-
tion of the tube is a cathode fo ower which passes
the positive phase signa . The other section inverts
the negative phase signa . The two outputs are com-
bined and feed to the input/phase inverter stage de-
scribed above. Common mode rejection is greater
than 60 dB at mid frequencies.
S ide switches at the rear of the chassis a ow se-
ecting ba anced or unba anced inputs and to se ect
input signa sensitivity of 1.2 vo ts or 2.5 vo ts for
fu power output. At the 1.2 vo t setting 1 vo t of in-
put signa wi produce 100 watts output. The s ide
switches operate reed re ays ocated at the front of
the chassis adjacent to the input circuits.
Refer to figure 21, MC2000 B ock Diagram of the
Power Supp y.
Power Transformers
Each power transformer inc udes two tapped primary
windings and three secondary windings. Refer to fig-
ure 21. The primary can be connected for 100, 120,
or 230 vo ts by p ug connections within the chassis.
A thermistor in series with the power ine input to the
transformer primary cushions the inrush surge cur-
rent. The high vo tage secondary winding feeds
bridge rectifiers fo owed by capacitor input fi ters.
A Power MOS FET is used in p ace of a fi ter choke,
fo owed by a arge output fi ter capacitor. The vo t-
age drop across the MOS FET is constant at a out-
put eve s resu ting in exce ent power supp y fi ter-
ing. A medium vo tage secondary winding feeds the
negative bias vo tage supp y. A ow vo tage second-
ary winding feeds the heaters of the output tubes,
driver tube and pane amps. This same winding a so
feeds regu ated DC power supp ies for the heaters of
the 12AX7A input stages and the meter circuits.
Power Meters
The power output of each amp ifier channe is moni-
tored by separate meters. The amp ifier output signa
is fed to a og converter amp ifier, then to a peak de-
tector, a pu se stretcher, then to a driver amp ifier and
the meter. The meter disp ays the output power being
de ivered by that channe and is ca ibrated in watts.
The Meter Switch on the front pane a ows the meter
to be switched from the norma output mode to a
Peak Ho d mode which a ows the meter to tempo-
rari y stay at the highest power reading during a
given time, with a gradua decay if power eve s drop.
The meter switch a so can turn off the meter amps
shou d that be desired.
The meter a so serves as an indicator for setting
the bias for the output tubes. At the side of the chassis
there are bias adjust contro s and sma push
switches. When a switch is pressed the amp ifier is
muted and the meter is connected to measure the cur-
rent f ow in the output tubes. The adjustment is not
critica and shou d on y be required when output
tubes are rep aced.
Power Control
The Power Switch has three positions, OFF, RE-
MOTE, and ON. OFF and ON a ow for manua op-
eration. REMOTE a ows power to be contro ed by a
command coming from a McIntosh Contro Center or
Preamp ifier. A red LED on the front pane ights to
indicate that the REMOTE position has been se-
ected, and the amp ifier is in the standby mode.

19
Technical Description, cont
Block Diagram
of t e
Power Supply Section
Figure 21
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20
Note: These Performance Charts are examples of typical performance of the MC2000.
-100
+0
20 20k50 100 200 500 1k 2k 5k 10k
Hz (Hertz)
dB
(Decibel)
Signal to Noise Ratio FFT Spectrum Analysis
ref. full power
-25
+0
-20
-15
-10
-5
10 100k20 50 100 200 500 1k 2k 5k 10k 20k 50k
dB
(Decibel)
Hz (Hertz)
Frequency Response @ 1 Watt
THD
%
0.1
0.5
0.2
0.3
0.4
20 20k50 100 200 500 1k 2k 5k 10k
Hz (Hertz)
Total Harmonic Distortion vs. Frequency @ 8 Ohms