McIntosh MA-6100 Service manual

MA

PREAMP AMPLIFIER

6100

SERVICE INFORMATION

STARTING WITH SERIAL NO. AE1001

MclNTOSH LABORATORY INC. 2 CHAMBERS STREET BINGHAMTON, NEW YORK

MA

6100

MA

6100

PERFORMANCE LIMITS

PERFORMANCE

Mclntosh audio power ratings are in accordance
with the Federal Trade Commission Regulation of
November 4, 1974 concerning power output claims
for amplifiers used in home entertainment products.

POWER OUTPUT

70 watts minimum sine wave continuous
average power output, per channel,
both channels operating into 8 ohms

load impedance which is:

23.7 volts RMS across 8 ohms

40 watts minimum sine wave continuous

average power output, per channel,
both channels operating into 16 ohms
load impedance which is:

25.3 volts RMS across 16 ohms

OUTPUT LOAD IMPEDANCE

8 ohms or 16 ohms

RATED POWER BAND

20 Hz to 20,000 Hz

TOTAL HARMONIC DISTORTION

0.2% maximum harmonic distortion at
any power level from 250 milliwatts to

rated power per channel from 20 Hz to
20,000 Hz, both channels operating

INTERMODULATION DISTORTION

0.2% if instantaneous peak power output is twice

rated continuous average power or less per channel
with both channels operating for any combination of
frequencies 20 Hz to 20,000 Hz

FREQUENCY RESPONSE

20 Hz to 20,000 Hz +0 -0.5 dB at rated power

NOISE AND HUM

Power amplifier: 95 dB below rated output
Aux, Tape, Tuner: 90 dB below rated output
Phono Input, Tape Hd.: 76 dB below 10 mV input

OUTPUT VOLTAGE

RATINGS

At TAPE output: Aux, Tape, Tuner: 300 mV with

input
Phono: 300 mV with rated input;

1.2 volts with 1.0 mV input at 1000

Hz

Tape Hd: 300 mV at 500 Hz with

rated input

DAMPING FACTOR

50 at 8 ohms output

100 at 16 ohms output

INPUT SENSITIVITY AND IMPEDANCE

Power Amplifier: 3 volts, 100,000 ohms
Phono 1 and Phono 2: 2.5 mV at 1000 Hz, 47,000
ohms
Tape Head: 3 mV, 47,000 ohms
Tape, Aux, and Tuner: 300 mV, 250,000 ohms

BASS CONTROLS

+ 16 dB to -16 dB at 20 Hz

TREBLE CONTROLS

+ 16 dB to -16 dB at 20,000 Hz

LF FILTER

Active filter, 12 dB per octave rolloff below 50 Hz;
20 dB down at 20 Hz

HF FILTER

Active filter, 12 dB per octave rolloff above 7000 Hz;
20 dB down at 20,000 Hz

GENERAL INFORMATION

SEMICONDUCTOR COMPLEMENT

36 Silicon Transitors, 22 Silicon Rectifiers and Di­odes, 2 Silicon Bilateral Switches, 2 Triac

POWER REQUIREMENTS

120 Volts, 50/60 Hz, 50 watts at zero signal output,
380 watts at rated output

MECHANICAL INFORMATION

SIZE

Front panel measures 16 inches wide (40.64 cm) by
5 7/16 inches high (13.81 cm). Chassis measures
15 inches wide (38.1 cm) by 13 inches deep (33.02
cm), including Panloc shelf and back panel con­nectors. Knob clearance required is 1½ (3.81 cm) in

front of mounting panel

WEIGHT

34 pounds (15.42 kg) net, 46 pounds (20.87 kg) in
shipping carton

MA6100 BLOCK DIAGRAM

MA

6100

MA 6100

TONE

&

VOLUME

CONTROL

NOTE 10

PC

BOARD

044-514

LEFT

CHANNEL PREAMP

PC

BOARD

044-512

RIGHT

CHANNEL

PREAMP

PC

BOARD

044-512

EQUALIZATION

PC

BOARD

044-420

PREAMP SECTION

MA 6100

154-632

MA

6100

MA

6100

MA6IOO

POWER OUTPUT

SECTION

154-631

LEFT CHANNEL
POWER OUTPUT
PC

BOARD

044-480

MA

6100

RIGHT CHANNEL
POWER OUTPUT
PC

BOARD

044-480

MA

6100

REG &

PHASE INVERTER

PC

BOARD

044-419

Q417
Q415

TOP

BOTTOM

Q418
Q416

LOCATION OF TRANSISTORS NOT ON PC BOARD

TOP

BOTTOM

MA

6100

POWER SUPPLY

SECTION

MA6IOO 154-616

MA 6100 SCHEMATIC NOTES

1. Unless otherwise specified: Resistance values are in ohms , 1/4 watt,
and 10% tolerance; Capacitance values smaller then 1 are in microfarads

(µF); capacitance values greater than 1 are in picofarads (pF);
inductors are in microhenries ( µH) .

2 . Printed circuit board components are outlined on the schematics by

dotted lines. The circled numbers around the dotted lines correspond

to the numbers on the PC Board layouts.

3 . The heavy lines on the schematics denote the primary signal path.

4. The terminal numbering of rotary switches is for reference only.
5 . All voltages indicated on the schematics are measured under the

fol1ow ing conditions:
a. Use of an 11 megohm input impedance VTVM.
b. All voltages ±10% with respect to chassis ground.
c. No signal at input terminals.
d. AC

input

at 120

e. Front panel controls at:

Volume Ful1y CW Tape mon. out

Input selector Aux Tape copy out
Mode selector Stereo Filters out
Balance control Zero Phase out

volts,

50/60

Hz.

Como Flat Speakers out
Tone controls Flat

6. In units with Serial No's below AE1453; C415 & C416 are 1000pF.
C413 & C414 are 1000µF and C407 & C408 are 470pF.

7. In early export units R429, R430, R447 & R448 are 47

8. In units with Serial No's below AE2557; CI17 and C118 are 12pF.

9. In units with Serial No's below AE2075; R309 is D308. (Mclntosh
Part No. 070-064)

10. In units with Serial No's below AE2122; R211 & R212 are Mclntosh
Part No. 134-354 and R227 & R228 are Mclntosh Part No. 134-253.

11. In units with Serial No's below AE3988; R421 , R422, R423 & R424
are 100 5% 1/2W; R425, R426, R427, & R428 are used; D417,
D418, D419 & D420 are not used; R437 and R438 are used and D4I5
and D416 are not used.

MA

6100

REPLACEMENT PARTS

All parts not listed are common items obtain­able from radio parts jobbers.

Replacement parts may be obtained when ordered
by

PART

Symbol
Number

C101

, 102

C105,

106

C107,108

C111

, 112

C113, 114
C115,116

C119,

120

C123,

124

C125,126
C127,

128

C129,

130

CI31

,132

C137,138

C201 ,202

C209.210

C212

,213

C301

C302
C303
C305

C306

C307

C312

C313,314

C317
C401 ,402

C403,404
C419,420
C427,428

D301 ,302

D303,304
D305,306
D307

NUMBER

from:

Mclntosh Laboratory, Inc.

C us tomer Service Department
2 Chambers Street
Binghamton, New York 13903

( telephone [phone])

CAPACITORS

Description
Mylar . 47µF
Ta. Elect 10µF
Ta. Elect 10µF
Mylar . 4µF
Ta. Elect- 100µF
Mylar . 1 µF
Mylar . 22 µF

Ta. Elect 100µF
Mylar .22µF

Mylar . 1 µF

Mylar .022µF
Mylar .01µF
Mylar .47µF
Mylar .22µF
Mylar .01µF

Mylar .022µF
Mylar . 47µF
Ta. Elect 10µF
Elect. 33µF
Mylar .22µF
Mylar 1µF

Elect. 100µF

Elect . 80/150/150/200µF

200/200/150/100V
Elect. 9300µF
Elect. 220µF

Elect. 150µF

Elect. 470µF

Elect. 10µF
Ta. Elect 1.5µF

DIODES

S i . Rect i f i er

S i . Rect i f ier
S i . Rect i fier
Zener

250V

63V
63V

250V

16V

250V

16V

250V

250V
250V
250V
250V
250V
250V
250V

63V
40V

250V

40V

50V

100V

63V

4V

35V

20V

75V

Part

Number
064-069

066-221
066-178
064-069
066-226
064-067
064-068

066-226

064-068
064-067

064-102
064-040
064-069
064-068
064-040
064-102
064-069
066-221
066-204
064-096
064-088

066-206
066-191

066-162
066-201

066-?05
066-136

066-173
066-158

070-041
070-041

070-031
070-025

D417,418

D419,420

0308

D309

D401 ,402

D403,404

D405,406
D407,408
D409,410

D411 ,412

D413,414
D415,416

F401 ,402

F403,404
CB301

L401 ,402

Q101

, 102

Q

103,

104

Q105, 106

Q107,

108

QI09,

110

Ql11 , 112

Ql13,

114

Q115,

116

Q301

Q302
Q303

Q401 ,402

Q403 ,404

Q405,406
Q407,408
Q409,410

Q411

,412

Q413,

414

Q415,416

Q417

,418

R20I
R2IO

R21 1
R212

Si. Rectifier

Si. Rectifier
Si. Rectifier

Zener 20V

Si. Rectifier
Si. Rectifier
Si. Rectifier
Si. Rectifier
Si. Rectifier
Si. Rectifier

Ge. PNP Transistor

Si. Rectifier

FUSES
Fuse 5A
Fuse 5A
Circu i t B reaker 4A

CHOKES
Choke 4µH

TRANSISTORS
Si . PNP transi stor
S i . PNP trans istor
S i . NPN trans istor
S i . NPN trans i stor
S i . NPN t rans i stor
S i . NPN trans i stor
S i . NPN transi stor
S i . NPN t rans i s tor
SI. NPN t rans i s tor
S i . PNP trans i stor
S i . NPN trans i stor
S i . PNP trans i stor
Si. PNP trans i stor
Si. NPN t rans istor

S i . NPN trans istor
Si. PNP t rans i stor
Si. NPN transistor
Si . PNP transi stor
S i . NPN t rans istor

S i . NPN trans i stor

POTENTIOMETERS
Ba l ance con t ro l
Vo 1 ume cont ro l

Bass trim con t ro l
Bass trim control

070-046
070-046
070-031

070-064
070-047

070-046
070-047
070-047
070-031
070-031

132-098

070-047

089-014
089-014

088-007

122-105

132-096
132-096
132-095
132-093
132-093
132-093
132-095
132-095
132-094
132-096
132-078

132-056
132-056

132-081
132-021
132-032
132-080

132-079
132-128
132-128

134-240
134-239

134-354
134-254

R215

R2I6
R227

R228

R3I3

R314
R401 ,402

R433,434
R435,436

SI
S2
S3

T30I

SBS401 ,402
TR401 ,402

MA

6100 SCHEMATIC PART

Treble control
Bass control
Treble trim control

Treble trim control

Wirewound 600 5W
Wirewound 1 . 5K 5W
Wirewound 3 . 6K 1 0W
Wirewound . 33 5W
Wirewound .33 5W

Input selector switch
Pushbutton switch
Mode selector switch

TRANSFORMERS

Power t rans former
THYRISTORS & TRIGGERS
Bilateral switch
Triac

FRONT PANEL & TRIM
Front panel
F ron t pane l end caps
Balance control knob
Comp cont ro l knob
Bass knob ( f ron t )
Bass knob ( rea r )

Treble knob (front)
Treb le knob ( rear )
Vo l u me con t ro l knob
Mode selector knob

Input selector knob

Pane l ill urn i na t i on # 1 866
Switch indicator #51

MOUNTING SYSTEM

She l f bracket (right)

Shelf bracket (left)
Mount i ng temp l a te # 1 00

Hardwa re package

MISCELLANEOUS ITEMS

Plastic feet

Sh i pp i ng ca r ton

Owners manua l

L i ne cord

POTENTIOMETERS

RESISTORS

SWITCHES

LAMPS

NO.

038-810

134-238
134-237
134-253

134-253

139-043
139-079
139-047
139-080
139-080

146-153
150-01 1
146-134

044-418

131

-004

131-005

044-423
018-154

044-375
090-100

044-375

090-100
044-375

090-

100

044-372
044-372
044-372

058-014
058-021

043-622

043-623
038-179

043-608

01 7-156

044-510
038-61

170-021

1

BE042004

20C1025S7-M4810

S.B.

SERVICE BULLETIN

WIRING CHANGE

MODEL: MA 6100 Preamp-Amplifier

PURPOSE OF MODIFICATION: To correct wiring error in compensation

and tone controls.

WHAT UNITS ARE AFFECTED: Serial No. AE1001 to AE1184

WHEN MODIFICATION SHOULD BE MADE: Any time any other service

is performed.

MA 6100

No. 1

MclNTOSH MODIFICATION KIT NO.: None

PARTS REQUIRED: None

PROCEDURE: (Refer to the diagram on reverse side)

Step 1 Remove dust cover, knobs & front panel.

Step 2 Interchange the orange and orange/white

wires connected to the tone control PC Board.

Step 3 Interchange the brown and brown/white

wires connected to the tone control PC Board.

Step 4 Remove 4 screws from upper section of sub

panel and interchange the green and green/white
wires connected to the volume control (R21O).

Step 5 Replace upper section of sub panel making sure

to use the hex head screws in the top holes
and the pan head screws in the lower holes .
Rep lace front panel, knobs and dust cover.

BE042003

Mclntosh Laboratory Incorporated 2 Chambers Street Binghamton, New York 13903 Phone: Area Code 607-723-3512

BOARD
PC

R2IO

VOLUME

TONE CONTROL

CONTROL

VIEW

TOP

3

STEP

REMOVED

COVER

2

DUST

STEP

ORANGE

BROWN

BROWN-WHITE

ORANGE-WHITE

PANEL

SUB

UNIT

UPPER

OF

FRONT

SERVICE BULLETIN

MODIFICATION OF INSTALLATION PROCEDURE

MODEL: MA 6100 Preamp-Amp1ifier

PURPOSE OF MODIFICATION: To prevent front panel glass from

breaking when unit is installed. Screws shipped with
the unit can press against the back of the panel

causing glass to break.

WHAT

UNITS

ARE

AFFECTED:

Serial

No.

7026

To

7439

Export

Serial No. AE1001 To AE1137 Domestic
Other units outside of this serial no. group are not
affected.

MA

S.B.

6100

No. 2

WHEN MODIFICATION SHOULD BE MADE: When units are being

installed either in the customers custom installation

or our L 12 equipment cabinet.

PARTS REQUIRED;

4

or 4

PROCEDURE:

1. For custom installation - Follow the normal mounting

2. L 12 Cabinet Installation - Follow the normal mounting

#6-32

#6-32 x 1-1/4

x 3/4

instructions using the flathead screws mentioned

above

were shipped with unit.

instructions using the 6-32 x 3/4 flat head

machine screws mentioned above rather than the

fillister

L 12 cabinet.

Flat

rather

Head

Flat

than

head screws that

Machine

Head

the

Screws

Machine

fillister

are

Screws

head screws that

enclosed

with

each

038-682

BE042003

Mclntosh Laboratory Incorporated

Fillister
Head

2 Chambers Street Binghamton, New York 13903

Flat Head

Phone: Area Code 607-723-3512