McIntosh MC-2300 User Manual

THE

MclNTOSH

MC

2300

SOLID STATE STEREO POWER

AMPLIFIER

Price $1.25

The Mclntosh MC 2300 is a high quality, ex­tremely high power, solid state stereo ampli­fier. Because of the high power available it is
necessary to emphasize some prudent and
safe operating conditions.

1. Never connect or disconnect inputs or
outputs while the amplifier is turned on.
Loudspeakers can be damaged or de­stroyed by the high power available from
the instrument.

2. Never operate the amplifier with the power
cord plugged into an auxiliary AC power

outlet on source equipment. The amplifier
draws near 14 amperes at full power and
damage to the source equipment can
occur.

3. Do not operate the instrument plugged

into an ordinary extension cord. Heavy
duty extension cords (14 ga. or heavier)
have adequate wire size and will not over­heat.

4. Be cautious when lifting the instrument.

It weighs 128 pounds. Make certain that
what it is placed on can support the
weight.

Your MC 2300 Stereo Power Amplifier
will give you many years of pleasant
and satisfactory performance. If
you have any questions concerning
the operation or maintenance of
this instrument, please contact:

CUSTOMER SERVICE

Mclntosh Laboratory Inc.
2 Chambers Street
Binghamton, New York 13903
Phone: [phone]

Take Advantage of 3 years
of FREE Factory Service . . .

Fill in the Application NOW.

CONTENTS

GUARANTEE.... 1

INSTALLATION.... 3

HOW TO CONNECT....4,5

Stereophonic.... 6

Monophonic.... 7

FRONT PANEL INFORMATION.... 8

PERFORMANCE LIMITS.... 9

TYPICAL PERFORMANCE CHARTS....10

TECHNICAL DESCRIPTION....11

BLOCK DIAGRAM....16

Mclntosh Laboratory Incorporated guarantees this
Instrument to be capable of performance as adver­tised. We also guarantee the mechanical and elec­trical workmanship and components to be free of
defects for a period of 90 days from date of pur­chase. If such defects occur, Mclntosh Laboratory

An application for a FREE THREE YEAR FACTORY
SERVICE CONTRACT is included with this manual.
The terms of the contract are:

For Three Years from date of purchase —

1. Mclntosh will provide all parts, materials and

labor needed to return the measured performance
of the instrument to the original performance
limits free of any charge. The SERVICE CON­TRACT does not cover any shipping costs to and
from the authorized service agency or the factory.

2. Any Mclntosh authorized service agency will re-

pair all Mclntosh instruments at normal service
rates. To receive the free service under the terms
of the SERVICE CONTRACT, the SERVICE CON­TRACT CERTIFICATE must accompany the instru­ment when taken to the service agency.

3. Always have service done by a Mclntosh author-

ized service agency. If the instrument is modified
or damaged, as a result of unauthorized repair the
SERVICE CONTRACT will be cancelled. Damage
by improper use or mishandling is not covered by
the SERVICE CONTRACT.

Copyright © 1971 by Mclntosh Laboratory, Inc.

GUARANTEE

or one of its authorized agencies wilt repair the
defect at no cost to the purchaser. This guarantee
does not extend to components damaged by im­proper use nor does it extend to transportation to
and from the factory or service agency.

4. The SERVICE CONTRACT is issued to you as the
original purchaser. To protect you from misrepre­sentation this contract cannot be transferred to a
second owner.

5. The SERVICE CONTRACT is given to purchasers
who live In the 50 United States or Canada only.

6. For your protection Mclntosh selects Its dealers
carefully. Only one dealer in ten qualifies for a
Mclntosh franchise. To receive the SERVICE
CONTRACT your purchase must be made from a
Mclntosh franchised dealer.

7. Your completely filled In application for a SERV­ICE CONTRACT must be postmarked within 30
days of the date of purchase of the instrument.

8. To receive the SERVICE CONTRACT all informa­tion on the application must be filled in. The
SERVICE CONTRACT will be issued when the
completely filled in application is received at
Mclntosh Laboratory Incorporated in Binghamton,

New York. If the application is not received at
Mclntosh Laboratory, only the service offered
under the 90-day guarantee will apply.

2

Installation

Installation of the MC 2300 requires careful thought
about three important factors. They are the electrical
power to operate the unit, the weight and the heat
generated when the MC 2300 is operating.

The MC 2300 draws 1400 watts or about 14 am-

peres when operated at full power. Do not use ordi-

nary extension cords of any type. Heavy duty exten­sion cords (14 ga. or heavier) have adequate wire
size and will not overheat. Plug the AC power cord
directly into a wall outlet. Make certain that the AC
power outlet has at least 15 amperes capacity with
nothing else using the circuit. Do not plug the MC
2300 into an auxiliary AC power outlet on a pre­amplifier or other source equipment. If remote power
operation is required, an external relay arrangement
must be made.

Weight of the instrument is 128 pounds. Make
certain that the shelf on which it is to be mounted
can support that weight. If it is to be vertically
mounted, be certain the structure is capable of sup­porting the MC 2300.

Adequate ventilation extends the trouble-free life
of electronic instruments. It is generally found that
each 10° centigrade (18° F) rise in temperature re­duces the life of electrical insulation by one half.
Adequate ventilation is an inexpensive and effective
means of preventing insulation breakdown that re­sults from unnecessarily high operating tempera­tures. The direct benefit of adequate ventilation is

longer, trouble-free life. Provide a source for input
air and an outlet for the heated air. The heat gener­ated in the operation of the MC 2300 is exhausted
from the unit by two low noise, long life fans.

Cooling input air is drawn into the MC 2300

through the ventilation holes on the sides of the

MC 2300. The air passes over the tranformers, output

heat sinks and transistors; and, is blown out the back
of the instrument by the two fans. It is recommended
that at least 2 inches of clear space be provided on
each side.

To permit the fans to operate best, provide at least
5 inches of space at the rear of the instrument. A
source for input air and a means to exhaust the

heated air is necessary so that the heated air does
not recirculate through the MC 2300.

To install the unit in a cabinet the aluminum side

rails with the feet attached must be removed. The

rails are attached to the front panel by 8 #10-32

machine screws and to each side by 4 small clips.
Remove both the front panel screws and the four
clips from each side for cabinet mounting. The open­ing to fit the unit is 17¼ by 10¼ inches.

RACK INSTALLATION

The MC 2300 may be mounted in a standard 19"
rack by removing the aluminum side rails. If a stand­ard rack is used, the screws that held the aluminum
rails to the front panel are used to attach the MC
2300 to the rack. When rack mounted, the MC 2300
requires 10½ inches of panel space. Allow two
inches in front of the panel for the knobs. A depth of
17 inches plus ventilation space is required.

The MC 2300 can be slide mounted in a rack.
Tapped well nuts and internal structure bracing has
been added to both sides of the MC 2300 for use
with the Model CTS-116 side mounted slide assem­blies manufactured by Chassis-Trak Inc., Indian­apolis, Indiana.

3

How to Connect

INPUT

Stereo or twin amplifier operation:

Use shielded cables to connect the signal from the
preamplifier or signal source to the power amplifier.
All connection are made on the back panel of the
MC 2300.

For stereo operation the LEFT OUTPUT of the pre­amplifier should be connected to the LEFT INPUT of
the power amplifier. The RIGHT OUTPUT of the pre-

amplifier should be connected to the RIGHT/MONO
input of the power amplifier. In stereo or twin ampli­fier operation the MODE SWITCH must be in the
stereo position.

For twin amplifier operation a separate signal

source can be connected to each input.

To minimize the possibility of hum the shielded

leads shall be run parallel or loosely twisted to-

gether. Locate the cables away from AC power cords.

Monophonic or Single Channel operation:

A shielded cable from the signal source is con-

nected to the RIGHT/MONO input of the MC 2300.
The MODE SWITCH on the back panel of the ampli­fier must be placed in the MONO position. In the
MONO position the output of the right channel input
amplifier is fed to both left and right power amplifiers.
The LEFT INPUT is disconnected. Only the signal fed

into the RIGHT/MONO input will be amplified. Should

the MODE SWITCH be left in the STEREO position

and the output transformers be strapped to a mono-

phonic load, one channel will attempt to drive the
other and cause high circulating currents and over-

heating. Be certain that the MC 2300 is never oper-

ated in the stereo mode with the outputs connected
for monophonic operation.

OUTPUT

Stereo or twin amplifier operation:

To connect the left speaker first check the imped-

ance of the speaker which is usually identified on
the speaker itself or in the owner's manual. Connect
one lead from the common terminal of the speaker to
the LEFT CHANNEL OUTPUT terminal strip screw

COMmon. Connect the other terminal of the speaker

to the screw with the number corresponding to the
speaker impedance on the LEFT CHANNEL OUTPUT
terminal strip. The right channel speaker is con-

nected in the same manner on the RIGHT CHANNEL

OUTPUT terminal strip. For stereo or twin channel

operation it is not necessary to use the same impe­dance loudspeaker on each output. Connect each
channel for the impedance desired.

When multiple speakers are to be connected to
either or both outputs, the combined load impedance
must be calculated and the load connected to the

appropriate impedance tap. The following table will

aid in selecting the correct impedance match.

Load Load

impedance Connect impedance Connect

in ohms

0.4 to 0.9

0.9 to 1.8

1.8 to 3.6

If a load impedance is used that is lower than the

output impedance tap, then reduced power and pos­sible distortion will result. If a load impedance is used
that is higher than the output impedance tap, then

neither the signal nor the amplifier will be harmed but
the voltage available is limited to that stated at that

tap.

For constant voltage line operation:

25 volts Connect to 2 ohms
70 volts Connect to 16 ohms

Make all speaker connections at the amplifier only.

For multiple speaker operation, parallel the leads

from the speakers to the amplifier.

Because of the high power available from the MC

2300, be sure to use large diameter speaker leads. In

all cases, the leads to and from the speaker should
be twin conductor or twisted together.

Use lamp cord, bell wire, or wire with similar type
of insulation to connect the speakers to the ampli­fier. For the normally short distances of under 20 feet
between the amplifier and speaker #18 wire or larger

can be used. For distances over 20 feet between the
amplifier and speaker use larger diameter wire. Se-

lect the correct size wire for the wire distance from

the chart.

It is recommended that the DC resistance of the
speaker leads not be over 5% of the load impedance.
Up to 10% can be tolerated. Resistance of the leads
should be computed for the length of wire both to
and from the speaker or speakers.

to

0.5
1

2

in ohms

3.6 to 7.2

7.2 to

14.4

14.4

to 28

to

4
8

16

4