McIntosh MC 2000 Owners Manual

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Frank H. McIntosh

Gordon J. Gow

For Fifty Years

1999 is the 50 year ofbusiness
for Mclntosh Laboratory of
Binghamton, New York. It all
started when Frank H. Mclntosh
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 ZOHZ to
20,000HZ with low
distortion. Mr. Mcln-
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. Mclntosh assembled a
small team of talented and dedi-
cated people who shared his
ideas, and formed the original
Mclntosh 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 Mclntosh Laboratory, lnc.
Initially both Mr. Gow and Mr.
Painchaud were directly in-
volved in design engineering.

Mclntoshs First Amplifier

After months of research, the
dream had become reality. The
original Mclntosh Power Am-
plifier, the 50W1, was created.
This amplifier was the first that
could truly be described as High
Fidelity, with 50 watts output

The Original Mclntosh
50W] Power Amplifier

A Brief History of Mclntosh

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
B i n g h a m t o n ,
New York in
195 1 . At that time
the company
name was
changed to the
now familiar
Mclntosh Labora-
tory, lnc. Gordon
Gow advanced to
become Execu-
tive Vice Presi-
dent of Sales and
after Frank Mcln-
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

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Thank You

Thank you for your decision to own this Mclntosh
MC2000 Tube Power Amplifier. You now have The
Best. The Mclntosh dedication to Quality, is as-
surance that you will receive many years of musical
enjoyment 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
Mclntosh 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

The production number, purchase date and Mclntosh
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,
Mclntosh Co-Founder, to commemorate the 50 year
of business for Mclntosh 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
Mclntosh sound is The Sound of the Music Itself.

Technical Assistance

Ifat any time you have questions about your Mcln-
tosh product, contact your Mclntosh dealer who is
familiar with your Mclntosh equipment and any other
brands that may be part of your system. If you or
your dealer wish additional help concerning a sus-
pected problem, you can receive technical assistance
for all Mclntosh products at:

Mclntosh Laboratory, Inc.

2 Chambers Street
Binghamton, New York 13903
Phone: 607-723-3512

Fax: 607-723-3636

Customer Service

-
If it is determined that your Mclntosh product is in
need of repair, you can return it to your dealer. You
can also return it to the Mclntosh Laboratory Service
Department. For assistance on factory repair return
procedure, contact the Mclntosh Repair Department
at:

Mclntosh Laboratory, Inc.

2 Chambers Street
Binghamton, New York 13903
Phone: 607-723-3515

Fax: 607-723-1917

Copyright 1999 © by Mclntosh Laboratory, Inc.

Table of Contents

A Brief History of Mclntosh ................................... 2
The MC2000 was Designed by

Sidney A. Corderrnan
Thank You ............
Take a Moment .
Introduction .........
Technical Assistance
Customer Service
Table ofContents
Safety Instructions .........
Performance Features
Installation ........................
Rear Panel Connections
How to Connect .................................
Front Panel Controls and Displays
How to Operate and Set the Bias
Technical Description
Performance Charts
Specifications ......
Packing Instruction .

NOTE:
F or additional connection infiirmation, refer to the
owner S manualfir) for any campanentfir) connected to
the MC2000 Tube Power Ampli ier

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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 of260 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 impedance of your
loudspeakers, being careful to observe the correct

polarities. Output impedance connections of 2

ohms, 4 ohms and 8 ohms are provided.

Notes: I. If the impedance ofyour 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
(A WC) wire size or larger
If your loudspeaker cables are
100feet (76.2m) or less, use 10
(A WC) wire size or larger

Right
Speaker

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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 & 10.

Note: If the cables come without prepared ends,

proceed to How to prepare cable ends .

l Hill P
Figur; 2s[ Input: 9 hgum m

Banana plug connection:
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.

How to Connect the MCZOOO, cont

How to prepare cable ends:
A. Carefully remove sufficient insulation from

the cable ends tojust 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 & 13.

0.5 inches
12.7 cm

Figure n Figure12[ Figur013[

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

Left
Speaker

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Technical Description

In the late 1940s Frank 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- McIntosh Unity Coupled Output Circuit
tant features é '

that differen-
tiate it from
other de-
signs. First,
the output
tubes deliver
their power _/
from both #:ER

their plates J?

I mm

and their

cathodes, not Figure 19
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.

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

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, 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-
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 adj ust-
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

l6