McIntosh C-28 Owners manual

THE MCINTOSH C 28 SOLID STATE STEREO PREAMPLIFIER

Reading Time: 37 Minutes

Price $1.25

Your MC 28 Stereo Preamplifier
will give you many years of pleasant
and satisfactory performance. If you
have any questions, please contact:

CUSTOMER SERVICE

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

WARNING: TO PREVENT FIRE OR SHOCK

HAZARD, DO NOT EXPOSE THIS UNIT TO RAIN

OR MOISTURE.

Take Advantage of 3 years
of FREE Service . . .

Fill in the Application NOW.

CONTENTS

Adjusting The Top Panel Controls.. 8

Using The Front Panel Controls.. 9, 10

Using the Pushbuttons.. 11
Balancing Your Stereo .. 12, 13

Listening To Your Stereo.. 13

Performance Limits and Ratings .. 14, 15

Service Contract.. 1

Installation.. 2, 3

How to Connect.. 4, 5, 6, 7

Performance Charts.. 16

Technical Description.. 18

Block Diagram .. 20

THREE YEAR SERVICE CONTRACT

An application for a FREE THREE YEAR SERVICE CONTRACT is included with this manual.

The terms of the contract are: or mishandling is not covered by the SERV-

ICE CONTRACT.

4. The SERVICE CONTRACT is issued to you as

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
repair 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

authorized service agency. If the instrument

is modified or damaged, as a result of un-

authorized repair the SERVICE CONTRACT

will be cancelled. Damage by improper use

the original purchaser. To protect you from
misrepresentation this contract cannot be
transferred to a second owner.

5. For your protection Mclntosh selects only
dealers who have technical competence to
guide purchasers fairly, and provide service
when necessary. To receive the SERVICE
CONTRACT your purchase must be made
from a Mclntosh franchised dealer.

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

7. 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.

Copyright (c) 1970 By Mclntosh Laboratory Inc.

1

How To Connect

CONNECTING A RECORD PLAYER TO PHONO 1

Connect the cable from the "left" channel of the

record player into the "L" PHONO 1 input jack.

Connect the cable from the "right" channel of the
record player into the "R" PHONO 1 jack.

PHONO 2 is provided for the use of a second record
player.

Connect the cable from the "left" channel of the
record player into the "L" PHONO 2 input jack.

Connect the cable from the "right" channel of the

record player into the "R" PHONO 2 input jack.

CONNECTING A MICROPHONE

Connect the cable from the "left" microphone to
the "L" MIC input jack. Connect the cable from the
"right" microphone to the "R" MIC input jack.

CONNECTING A TAPE DECK FOR PLAYBACK

Connect the cable from the "left" tape recorder head
on the tape deck (one without its own electronics)
to the "L" TAPE HEAD input. Connect the cable
from the "right" tape recorder head to the "R" TAPE
HEAD input.

CONNECTING A STEREO TUNER

Connect the cable from the "left" channel tuner out­put to the "L" tuner input jack.

Connect the cable from the "right" channel tuner
output to the "R" TUNER jack.

AUX

Any high level program source such as another tuner
or a TV set can be connected to the input jacks
marked "AUX."

CONNECTING A TAPE RECORDER

To Record:

Connect a cable from the "L" TAPE OUTPUT jack

marked TAPE 1 to the "left" high level input tape

recorder.
Connect a cable from the "R" TAPE OUTPUT jack

marked TAPE 1 to the "right" high level input of the
tape recorder.

Connect a second tape recorder in the same fashion
to the TAPE 2 outputs.

To Playback Monitor: Connect the cable from the
"left" channel output of a tape recorder to the high
level inputs . . . "L" TAPE 1.

Connect the cable from the "right" channel output of
a tape recorder to the high level input . . . "R" TAPE.

Connect a second tape recorder in the same fashion
to the TAPE 2 input jacks.

4

5

CONNECTING THE C 28 TO POWER AMPLIFIERS

Connect the MAIN output jacks to the input of a
stereo power amplifier. The "L" jack is connected to
the "left" amplifier input jack. The "R" jack is con-

nected to the "right" amplifier input jack.

The output impedance at the MAIN outlet is 100

ohms. Longer cables than are supplied can be con­nected between the C 28 and the amplifiers. The
length of the cable is limited by the capacity of the
cable. The total capacity must not exceed 1000 pF.
For instance: cables with a capacity of 25 pF per

foot may be 40 feet long. 13.5 pF per foot cable

may be 75 feet long. The input impedance of the
amplifiers should be 47,000 ohms or greater.

CTR OUTPUT

Use the CTR output to feed left plus right signal to a

separate power amplifier for monophonic back-

ground music or for a center channel speaker.

SPEAKER CONTROL RELAY

To control main and remote loudspeakers from the
front panel of the C 28 an accessory Mclntosh SCR
control is needed. Plug the cable from the SCR con-

trol in the SPEAKER CONTROL RELAY receptacle.
The speakers are then connected to the SCR con-

trol. The AC outlets on the SCR have a total capa­city of 2400 watts.

AC OUTLETS

There are 4 black AC outlets, 2 green AC outlets,
and one red AC outlet. The power to the black AC
outlets is controlled by the front panel switch. Use
these outlets for a tuner, tape recorder, etc. The

green outlets are controlled by the top panel switch
marked "Power Amplifier." The total capacity of all
AC power outlets is 600 watts. To prevent burnout,
use the AC outlets on the CR for power requirements
exceeding 600 watts. The red receptacle is on at all
times. Use the red outlet for a turntable or record
changer. The turntable is protected by this arrange­ment. It is necessary to turn off the turntable or rec­ord changer with its own AC switch.

GROUND CONNECTION

A single ground post is provided. Grounds for turn­tables, record changers, tape decks, etc. should be
connected to this post. The left and right program
cables and the ground wire from that source should

be wound or twisted together. To avoid hum, make
sure the ground wire does not make any connec­tions to the shields of the left and right program
cables between the program source and the C 28.

6

7