McIntosh MC-30 User manual

INSTRUCTION MANUAL
MciNTOSH MODEL Me-30
U.S.A.
30 WATT POWER AMPLIFIER
Type A-116B
Serial # 15329 and Over
MciNTOSH LABORATORY, INC
2 Chambers St. Binghamton, N. Y.
1.5M·757·HPB

ELECTRICAL AND MECHANICAL SPECIFICATIONS
Specifications for the Mcintosh Model MC-30 Audio Amplifier
Power Supply 117/125 volts, 50/60 cycles
Power Consumption 135 watts at 30 watts output
105 watts at zero signal output
Power Output 30 watts continuous
Input Level Input # 1 (pin jack and screw terminals and pin 5
of pre-amp socket) .5 volts to 30 volts, with gain control
Input #2 (pin 2 of pre-amp socket) 2.5 volts, (For
use with McIntosh pre-amplifier equipment).
20 to 30,000 cycles -+- .1 db at 30 watts output
15 to 50,000 cycles -+- .5 db at 30 watts output
10 to 100,000 cycles -+- 1 db at 15 watts output
Frequency Range
Harmonic Distortion Less than 113% at 30 watts output or less, 20 to 20,000
cycles
Intermodulation Distortion Less than 112% if instantaneous peak power is below
60 watts for any combination of frequencies 20 to
20,000 cycles
Impulse Distortion Negligible
Noise and Hum Level 90 db or more below rated output
Damping Factor
Input Impedance
12 or better for 4,8 and 16 ohm output, 16 for 600 ohms
0.5 meg for 0.5 volt input and 0.13 meg for 2.5 volt
input. 20 cycles to 40 Kc
4,8, 16 and 600 ohms (600 ohm is balanced to ground)
20 cycles 3°
20,000 cycles 9°
Output Impedance
Size 13 x 8 x 8 high, chassis type construction
Phase Shift
Tube Complement Pre-Amp: 12AX7
Phase Inverter: 12AU7
Voltage Amp: 12BH7
Driver: 12AX7
Output: 2-1614
Rectifier: 5U4-GA
Auxiliary Equipment
connection ( Pre-Amp
input receptacle)
Designed to power C-8 and other McIntosh Pre-
Amplifiers
Weight 30.5 pounds net
Finish Chrome and Black
-1-

DESCRIPTION
The Mcintosh Model MC-30 is a 30 watt high fidelity power amplifier designed for home entertainment
systems and professional applications. The Model MC-30 is similar to the earlier Mcintosh Model A-116
30 watt amplifiers and includes all of the rigid electrical specifications and features found in these earlier
units plus: less than 1/3% harmonic distortion at any power output up to 30 watts and at any frequency in
the audio spectrum, 20 to 20,000 cps; less than 112% intermodulation distortion if instantaneous peak power
is below 60 watts for any combination of frequencies 20 to 20,000 cps; and noise and hum level 90 db or more
below rated output. The famous Mcintosh high efficiency output circuit is used to obtain the high standard
of performance found in this amplifier.
The MC-30 may be operated from any signal source delivering 0.5 or more volts, or directly from a
Mcintosh Audio Compensator or Pre-Amplifier, such as the Models C-8 C-4 C-I04 or C-108. Output im-
pedances of 4, 8 and 16 ohms are provided for direct connection to loudspeakers. An additional 600 ohm out-
put is present for use with lines, etc.
INST ALLA TION
Location
The MC-30 should be located in a ventilated area. If the amplifier IS housed m a cabinet or other en-
closure, holes should be provided for air circulation.
Input Connections
1. When a Mcintosh Audio Compensator or other Mcintosh pre-amplifier is used with the MC-30, plug
the pre-amplifier's output-power cord into the Pre-Amp input receptacle on the MC-30 and turn the gain
control fully counter clockwise. This receptacle supplies the required plate and filament power to the pre-
amplifier equipment as well as providing the necessary audio connection.
For pre-amplifier installation and operation refer to the pre-amplifier's instruction manual.
2. When a signal source of 0.5 volts or more is used to drive the amplifier, such as the output from a
tuner, tape recorder, or pre-amplifier, plug the source into the 0.5 volt input pin jack receptacle or con-
nect to the 0.5 volt and GND screw terminals. Use the gain control to obtain the desired operating
level.
2

If desired, the signal source may be wired to an octal plug for insertion in the octal Pre-Amp input re-
ceptacle. In this case connect the input lead to pin # 5 and the ground lead to pin # 1. When using this con-
nection the source must not have a DC output component.
Output Connections
The MC-30 has output impedances of 4, 8 and 16 ohms available at either the screw terminal connector
or the output socket. In addition, a 600 ohm output (balanced to ground) is available at the output socket.
See schematic diagram for socket connections.
It is important that the loudspeaker or other load be properly matched to the amplifier if best 'perform-
ance is to be obtained. Because many loudspeakers do not have voice coil impedances exactly matching 4, 8
and 16 ohms, the following table lists suggested connections for best impedance matching.
Speaker Impedance 3.2 to 6.5 ohms 6.5 to 13 ohms 13 to 32 ohms
Connect To
4 ohms 8 ohms 16 ohms
WARNING: Output plugs wired for McIntosh 20W-2 and 50W-2 amplifiers must not be used with
the MC-30 without rewiring the plug.
Power Connections
The MC-30 operates from any 110 to 130 volt 50-60 cycles power line. (When continuous use IS con-
templated on 120 to 130 line volts the transformer primary should be re-connected using the 125 volt tap.)
When the MC-30 is used with the McIntosh Pre-Amplifier equipment, tuners, or other associated equip-
ment the MC-30 power cord is plugged into the receptacle at the rear of these units. When thus connected
the power switch of these units controls the MC-30.
3

GUARANTEE
We guarantee the performance of this equipment and the mechanical and electrical workmanship to be
free of serious defects for a period of 90 days. This guarantee does not extend to components damaged by im-
proper use nor does it extend to transportation to and from the factory.
SERVICE INFORMATION
All McIntosh equipment 1S designed for long trouble free operation. All components are of highest
quality and are conservatively operated. If trouble develops the amplifier may be serviced by your franchised
dealer, a competent serviceman, or returned to the factory. Equipment will not be .accepted at the factory
unless factory return authorization is first received. The following chart of operating voltages and resistances
is offered as a guide for servicing the unit. All voltages and resistences are measured to chassis except
those with asterik (*). These are measured to chassis with pin #2 of either 5U4GA grounded. Voltages are
measured with high impedence VTVM. NOTE-UNIT MUST BE TURNED OFF WHEN MEASURING
RESISTENCES.
Tube
12AX7
(input)
12AU7
·12BH7
VOLTAGE AND RESISTANCE CHART
DC Volts
Pin No. No Signal
1120
2
-e-
3
1.1
4 & 5Filament
6,7 & 8
9Filament
1240
2120
3 & 8129
4 & 5Filament
6 240
7
96
9Filament
1352
2
iT
3 & 818
4 & 5Filament
6352
7
iT
9Filament
DC Volts
30Wout AC Volts
30Wout
102
iT
1.5
.42
1
(6.3V AC to pin 9)
.4
210
102
108
(6.3V AC to pin 9)
210
86
10
1.5
.5
10
iT
Resistance
Unit Off
380K*
27K (gain
C.C.W.)
3.3K
-&-(hum
C.C.W.)
40K*
380K*
18K
40K*
2.5K*
295 132 12.2Kx-
-&- 10 220K
15.5
.4
1.2K
(6.3V AC to pin 9)
295 132 12.2K*
iT
10 220K
--4-

DC Volts DC Volts AC Volts Resistance
Tube Pin No. No Signal 30Wout 30Wout Unit Off
12AX7 1440 375 98 205*
2-42 -41 132 l.1M
3-42 -42 132 150K
4 & 5 Filament (6.3V AC to pin 9)
6 440 375 98 205*
7-42 -41 132 l.1M
8-42 -42 132 150K
9Filament
1614 1
..g...
-o-
-o -e-
2Filament (6.3V AC to pin 7)
3440 375 98 205*
4440 375 98 205*
5-42 -42 132 150K
6
7 Filament
8
.8
5.5 98 19
5U4 1
2Filament 460 410 8.8 (ripple) 0*
3
4370 44
5
6370 44
7
8 Filament (5.0V AC to pin 2) 0*
5
U. S. Patents No. 2,477,074; 2,545,788; 2,646,467; 2,654,058 others pending
McINTOSH LABORATORY, INC.
2 Chambers Street
Binghamton, N. Y., U.S.A.
In Canada: Manufactured Under License by McCurdy Radio Industries, Ltd.
22 Front Street West, Toronto, Canada
l~~~ ~~ __ =======================~

Ou-tput Connections
Using Octal Socket
4 ohms - pins 1 and 2
8 ohms - p Lns 1 and 3
16 ohms - pins 1 nnd 4
600 ohms - plns 7 and 8
(pin 6 is CT and ground)
70.7 Volts - pins 5 and 6
(pin 6 is ground)
Pre-Amplifier Input
Soclce t Connections
Pi n 1 - ground
Pin 2 - pre-amp input (2. 5V)
Pin 3 - not used
Pin 4 - +310v at 3.5 ma ,
pin 5 - .Sv input
Pin 6 - not used
Pins 7 and 8 - 6.3V at lamp.
Note t - This jumper strap
mny be removed if ungrounded
low impedance outputs are
deslred.
Rl SOOK Pot. t Gain Adj.
R2 lOOK
R3 27K
R4 3.3M
R5 3. 3K
R6 68 ohms t 5%
R7 lOOK
R8 330K
R9 680K
RlO 18K, lW
Rll 1. 2M
R12 1M
R13 2.2K, 5%
R14 27K, 5%
R15 30K, 5%
R16 220K
R17 1.2K
RIB 220K
RIg 12K, 2W*
R20 12K, 2W*
R21 120K, 5%
R22 1M Cl
R23 820K, 5% C2
R24 1M C3
R25 220K C4
R26 220K C5
R27 10K, lOW C6
R28 150 ohm lOW C7
R29 250 ohm Pot. C8
R30 3.3K C9
R3I 2.2M CI0
R32 330K Cll
R33 220K C12A
R34 220K C12B
R35 IBOK C12C
*Matched to wi thin 1% C13
M·l 2.5 47
PRE-AMP INPUT OUTPUT
.n
,.INPUT-, ~OUTPUT-----,
5V. GND. GND.COM 4 8 16
J-t(Jr
1
7 2
6 3
5 4
:1[, ,
r , I ,
3 ~ I I
~' , .cr I I R I \ ' I I I
- ~NOTEI
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.5V INPUT
TO
FIL.
I
~
I
Q 0
-c::..
IM'150B
-L
C2
-rr--
1/ C8
Ir-
MclNTOSti LABORATORY, INC.
SERIAL NOS. 15329 AND ABOVE
n
MODEL MC-30, TYPE A-116B, POWER AMPLIfiER
MC-30'4
D TI' 5·15-56
J,W.C.
ll-
RI
GAIN
· lmf, 400V
· 47mf, 2DOV
100mf, 12wv
· 22mf, 400V
· 22mf, 400V
· Imf t 400V
470mmf, 500V
.047mf, 600V
.04 7mf J 600V
· 25mf, 60DV
.25mf, 600y
40mf, 500V
80mf, 450V
20mf, 450V
10mf, 450V
RI3
I I '\ \ 'vI I I I I
II
RECf. R30 M·152B
~
TOFIL.
R29
-= -= HUM ADJ.
L- ---l111 TO FIL.
IRI4~ R16~
U Ii S'"
~
15 ~18~
8L
7
6
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o
o
_ 0
0
c :z4 •••..
.1\--
I-='-
~R24 ~
R26
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I\C7

marrant~
Mcintosh laboratory warrants the electrical and mechanical workmanship and compo-
nents of this equipment to be free of serious defects for a period of 90 days provided the enclosed
warranty card is duly completed and returned to Mcintosh laboratory.
Mcintosh laboratory further warrants the transformers supplied as components of this
equipment to be free of manufacturing defects for a period of 1 year from the date of shipment
from the factory. Mcintosh laboratory will replace at no charge any such transformer failing to
meet this warranty period.
This warranty does not extend to components or transformers damaged by improper use,
nor does it extend to transportation to and from the factory.
~ «:» t ~+VSL-,
mcintosh Laboratory, Inc.
2 CHAMBERS ST. , BINGHAMTON, NEW YORK
©GOES Mao