Marantz Pm-6a User manual

MARANTZ

DESIGN

AND

SERVICE

Using

superior

design

and

selected

high

grade

components,

MARANTZ

company

has

created

the

ultimate

in

stereo

sound.

Only

original

MARANTZ

parts

can

insure

that

your

MARANTZ

product

will

continue

to

perform

to

the

specifications

for

which

it

is

famous.

Parts

for

your

MARANTZ

equipment

are

generally

available

to

our

National

Marantz

Subsidiary

or

Agent.

ORDERING

PARTS:

Parts

can

be

ordered

either

by

mail

or

by

telex.

in

both

cases,

MARANTZ

part

number

has

to

be

specified.

!f

you

order

by

_

mail,

fulfil

MARANTZ

order

forms.

MARANTZ

S.A.

EUROPEAN

PARTS

DEPARTMENT

.

2,

Avenue

Léopold

III

B-7120

PERONNES-lez-BINCHE

BELGIUM

5

TWX:

57589

SEPLT

B

The

following

information

must

be

supplied

to

eliminate

delays

in

processing

your

order:

Complete

address

Complete

part

numbers

and

quantities

required

Description

of

parts

Model

number

for

which

part

is

required

Way

of

shipment

Signature:

any

order

form

or

telex

must

be

signed

otherwise

such

part

order

will

be

considered

as

null

and

void,

An

PWN

=

PARTS

ORDERING:

Parts

may

be

ordered

from

the

following

addresses:

EUROPE

MARANTZ

S.A.

MARANTZ

NORSKE

A.S.

MARANTZ

DENMARK

MARANTZ

GMBH

AUSTRIA

European

Parts

Department

Refstadalleen

13

Bregnergdvej

132b

Wiedner

Hauptstrasse

98

2,

Avenue

Léopold

III

Oslo

5

3460

Birkergd

1050

Wien

B-7120

Péronnes-lez-Binche

Norway

Denmark

Austria

Belgium

Telex:

19659

Telex:

39137

Telex:

113583

Telex:

57589

MARANTZ

S.A.

MARANTZ

FRANCE

MARANTZ

BELGIUM

MARANTZ

SVENSKA

A.B.

326

Avenue

Louise

Bte

32

4

Rue

Bernard

Palissy

45

Rue

Auguste

Van

Zande

Svartviksvangen

56

1050

Brussels

92600

Asniéres

1080

Brussels

Traneberg

-

Box

12016

Belgium

France

Belgium

16112

Bromma

Telex:

26602

Telex:

611651

Sweden

Telex:

13449

MARANTZ

GERMANY

GMBH

MARANTZ

AUDIO

U.K.

LTD.

Max

Planckstrasse,

22

Unit

15/16

6072

DREIEICH

1

Saxon

Way

Industrial

Estate

West

Germany

Moor

Lane

Telex:

4185316

Harmondsworth

UB7

OLW

Great

Britain

Telex:

935196

AUSTRALIA

MARANTZ

AUSTRALIA

PTY.,

LTD.

32

Cross

Street

Brookvale,

N.S.W.

2100

Australia

Telex:

24121

All

of

the

above

locations

are

fully

equipped

to

take

care

of

your

total

service

needs.

Because

various

countries

have

differing

configuration

requirements,

it is

necessary

that

you

contact

the

service

facility

in

your

particular

country.

in

the

event

that

there

is

no

service

location

listed

for

your

country,

please,

contact

the

nearest

facility

for

the

necessary

assistance.

In

case

of

difficulties,

do

not

hesitate

to

contact

the

Technical

Department

at

abovementioned

address.

ERR

em

Been

BRE

Z*

TABLE

OF

CONTENTS

INTRODUCTION:

i

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ccccetn

Se

lore

hh

ee

Sree

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heat

aes

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BMA

SR

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WB

ake

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as

1

1:

HRBEATURES

woireue

at

oo

pce

este

ode

en

acl

eeties

Rapti

Aale

Wien

aA

Bee

GDR

ele

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Ste

Baan

1

2.

PAW

BOARDS

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ORE

RE

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2

3.

TEST

EQUIPMENT

REQUIRED

FOR

SERVICING

............

0.0002

cece

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eee

eens

3

4.

ADJUSTMENT

PROCEDURES

............

0.0.0

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ete

enn

eeaes

3

5.

VOLTAGE

CONVERSION

..

10...

0...

ccc

cc

ee

ete

ee

ete

eee

eens

4

6...

BROCK

DIAGRAM

asi

ce

ociod

ech

eek

kel

oe

Bee

Seared

edb

8

Was

EO

Sie

ew

SE

eae

and

ee

Se

es

5

7.

DIAGRAM

AND

COMPONENT

LOCATIONS

.............0

cc

cece

eee

ere

eee

teens

6

7.1.

Filter

Assembly

(PHOO)

Schematic

Diagram

and

Component

Locations............000

ee

eee

eteees

6

7.2

Speaker

Switch

Assembly

(PW00)

Schematic

Diagram

and

Component

Locations

............202e0005

6

7.3.

Voltage

Amp.

Assembly

(P700)

Schematic

Diagram

and

Component

Locations

.............00200205

6

7.4

Ripple

Filter

Assembly

(PCOO)

Schematic

Diagram

and

Component

Locations

......:......0+020208%

6

75

Loudness

Assembly

(PFO0)

Schematic

Diagram

and

Component

Locations

............000

000s

e

eee

6

76

ASO

Protector

Assembly

(PNOO)

Schematic

Diagram

and

Component

Locations

.........

gang

a

ar

tede

an

Soat

7

7.7

Test

Point

Assembly

(PJOO)

Schematic

Diagram

and

Component

Locations

.............00

000

eters

7

78

Tone

Amp.

Assembly

(PEO1)

Schematic

Diagram

and

Component

Locations...............00

000802

8

79

Tone

On-Off

Assembly

(PS00)

Schematic

Diagram

and

Component

Locations

............00002+

000%

8

7.10

Pre-Amp.

Assembly

(P400)

Schematic

Diagram

and

Component

Locations

..............0200e00888

9

7.11

Transistor

Block

Assembly

(P401)

Schematic

Diagram

and

Component

Locations

............0000005

9

7.12

MC

Transistor

Block

Assembly

(PM01)

Schematic

Diagram

and

Component

Locations

..........-+++-.

9

7.13

Head

Phone

Assembly

(PX00)

Schematic

Diagram

and

Component

Locations

............-.2008880

8%

10

7.14

A-B

Detector

Assembly

(PLOO)

Schematic

Diagram

and

Component

Locations

.............22+2205

11

7.15

A-B

Power

Switch

Assembly

(PKO0)

Schematic

Diagram

and

Component

Locations

...........---++5

11

7.16

Power

Amp.

Assembly

(P600)

Schematic

Diagram

and

Component

Locations

.............

00200228

12

7.17

Mode/Balance/Vol.

Assembly

(PGOO)

Schematic

Diagram

and

Component

Locations

.........-+-.+-+-

12

7.18

L.E.D.

Power

Ind.

Assembly

(PY00)

Schematic

Diagram

and

Component

Locations

............08065%

13

7.19

Phone

Input

Assembly

(PV00)

Schematic

Diagram

and

Component

Locations

............0.-2+¢e55

13

8.

EXPLODED

VIEW

AND

PARTS

LIST

.........

0.0.0...

cece

ee

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14

9;

PLEGTRICAL,

PARIS

LIST

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ier

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USE

coelate

21

10.

TECHNICAL

SPECIFICATIONS

.........

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30

11.

SCHEMATIC

DIAGRAM

.......

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erence

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etenee

32

MARANTZ

MODEL

Pm-6A

STEREO

PRE

MAIN

AMPLIFIER

INTRODUCTION

This

service

manual

was

prepared

for

use

by

Authorized

Warranty

Staions

and

contains

service

information

for

the

Marantz

Model

Pm-6a

Stereo

Pre

Main

Amplifier.

Servicing

information

and

voltage

data

included

in

this

manual

are

intended

for

use

by

knowledgeable

and

ex-

perienced

personnel

only.

All

instructions

should

be

read

carefully.

No

attempt

should

be

made

to

proceed

without

a

good

understanding

of

circuitry

operation.

The

parts

list

furnishes

complete

ordering

information.

Most

replacement

parts

should:

be

ordered

from

the

Marantz

Company.

However,

a

simple

description

is

included

for

parts

which

can

be

obtained

locally.

coveiiie

wees

nectean

TREY

See

1.

FEATURES

@

MC

Head

Amplifier

(13

transistors

for

each

channel)

The

first

stage

of

the

MC

head

amplifier

is

a

push-pull

amplifier

consisting

of

4

very

low

noise

NPN

transistors

and

4

very

low

noise

PNP

transistors.

The

second

stage

is

also

a

push

pull

amplifier,

and

the

output

stage

is

a

SEPP

amplifier.

The

feedback

circuit

impedance

is

reduced

as

much

as

possible

to

improve

the

S/N

ratio,

and

a

voltage

gain

of

20

dB

(10

times)

is

obtained

at

a

rated

input

level

of

125

uV.

@

PHONO

Amplifier

(11

transistors

for

each

channel)

The

PHONO

amplifier

uses

a

full

push-pull

circuit

con-

sisting

of

11

transistors

for

each

channel

so

that

low

TIM

distortion

and

a

high

S/N

ratio

are

obtained.

The

first

stage

is

a

push-pull

circuit

consisting

of

very

low

noise,

high

Gm

N

and

P

channel

FETs

combined

with

a

cascode

current

Miller

circuit

so

that

degradation

of

following

stage

characteristics

due

to

input

stage

im-

pedance

fluctuation

is

prevented.

The

second

stage

consists

of

an

emitter

follower

buffer

amplifier

and

a

push-pull

voltage

amplifier.

The

output

stage

uses

a

SEPP

circuit

which

is

adequate

to

drive

any

type

of

load.

The

equalizer

elements

have

very

low

impedances

compared

with

conventional

circuits

so

a

S/N

ratio

of

90

dB

is

obtained

at

the

rated

input

level.

The

equalizer

elements

are

metal

film

resistors

with

tolerances

of

1%

and

polypropylene

capacitors

with

tolerances

of

2%;

this

makes

it

possible

to

obtaine

an

RIAA

phono

equalization

of

+0.2

dB

over

the

audio

range

from

20

Hz

—

20

kHz.

Input

impedances

27

kQ,

47

kQ

and

100

kQ

are

provided

for

different

types

of cartridges

when

the

PHONO

1

input

is

selected.

The

PHONO

amplifier

output

circuit

is

provided

with

a

relay

to

mute

undesirable

noise

when

the

power

is

switched

ON

and

OFF,

and

with

a

EQ

subsonic

filter

to

reduce

turntable

rumble

and

flutter.

Quarter

A

System

The

quarter

A

system

automatically

switches

the

bias

current

and

supply

voltage

to

the

main

amplifier

by

de-

tecting

the

main

amplifier

input

voltage

and

speaker

current;

thus,

the

main

amplifier

operates

in

class

A

when

the

power

output

is

up

to

30W/8Q,

and

in

class

AB

when

the

power

output

exceeds

that

level.

The

phase

correction

circuit

in

the

detection

circuit

prevents

distortion

from

being

generated

even

if

a

wave-

form

with

a

sharp

rising

edge

is

applied.

Marantz’s

usual

superb

amplifier

circuit

has

not

been

altered

in

this

system,

except

that

the

detection

circuit

is

connected

to

the

signal

system.

Voltage

amplifier

The

input

circuit

of

the

voltage

amplifier

is

a

source

follower

using

a

pair

of

FETs,

so

variation

in

the

im-

pedance

of

this

stage

does

not

influence

following

stage

characteristics.

The

is

a

differential

amplifier

using

a

dual

transistor,

followed

by

an

active

balance

loading

circuit

using

a

dual

transistor.

One

of

the

differential

amplifier

output

signals

is

phase-

inverted,

then

both

signals

are

applied

to

the

push-pull

amplifier

through

the

emitter

follower

buffer.

Power

amplifier

The

power

amplifier

employs

triple

Darlington

connection

and

supper

high

f—

power

transistors

connected

in

paral-

lel.

The

power

amplifier

uses

unique

push-pull

circuit

with

ex-

cellent

open

loop

characteristics

and

a

2-pole

phase

com-

pensation

circuit,

so

the

frequency

response

is

flat

even

at

high

frequencies

and

TIM

distortion

is

reduced

remark-

ably,

Other

features

The

speaker

protection

circuit

uses

a

high

performance

IC

and

relay.

The

power

supply

circuit

uses

a

large

trans-

former

with

high

regulation

and

newly

developed,

large

capacity

custom

electrolytic

capacitors.

To

obtain

continuous

high

power

output,

high

efficiency

heat

pipes

are

used

to

radiate

the

heat

produced

by

the

power

transistors.

2.

P.W.

BOARDS

As

can

be

seen

from

the

circuit

diagram

the

chassis

of

Model

Pm-6a

consists

of

the

following

units.

Each

unit

mounted

on

a

printed

circuit

board

is

descrided

within

the

square

enclosed

by

a

bold

dotted

line

on

the

circuit

diagram.

wie

etd

a

i

etd

td

OWONAMAWN=|

—_

SOMNOTARWN

A

.

Pre-Amp.

........--

mounted

on

.

Transistor

Block

.....

mounted

on

.

Power

Amp.

.......

mounted

on

.

Voltage

Amp.

......

mounted

on

Ripple

Filter

.......

mounted

on

.

Tone

Amp.

........

mounted

on

.

Loudness

.........

mounted

on

.

Mode/Balance/Vol.

...

mounted

on

SF

HteR

ss.

eet

ees

mounted

on

.

TestPoint.........

mounted

on

.

A-B

Power

Switch.

...

mounted

on

.

A-B

Detector

.......

mounted

on

.

MC

Transistor

Block

..

mounted

on

.

ASO

Protector

......

mounted

on

Tone

On-Off

.......

mounted

on

.

Phone

Input

.......

mounted

on

.

Speaker

Switch

.....

mounted

on

.

Head

Phone...

.....

mounted

on

L.E.D.

Power

Ind..

...

mounted

on

P.W.

Board

P400

Board

P401

Board

P600

Board

P700

Board

PCO0O

Board

PEO1

Board

PFOO

Board

PGOO

Board

PHOO

Board

PJOO

Board

PKOO

Board

PLOO

Board

PM01

Board

PNOO

Board

PSOO

Board

PV00

Board

PW00

Board

PX00

Board

PYO0

3.

TEST

EQUIPMENT

REQUIRED

FOR

SERVICING

This

table

lists

the

test

equipment

required

for

servicing

the

Model

Pm-6a

Stereo

Pre

Main

Amplifier.

Distortion

Analyzer

Audio

Oscillator

AC

VTVM

Oscilloscope

Circuit

Tester

DC

VTVM

aa

|

Use

Distortion

measurements

Sinewave

and

squarewave

signal

source

LLL

Voltage

measurements

(AC)

Waveform

analysis

and

trouble

shooting

and

ASO

alignment

Trouble

shooting

—

AC

Wattmeter

Line

Voltmeter

Variable

Autotransformer

(0

~

140V

AC,

10A)

Shorting

Plug

Voltage

measurements

(DC)

Monitors

primary

power

to

amplifier

Monitors

potential

of

primary

power

to

amplifier

Adjust

level

of

primery

power

to

amplifier

lezen

4.

ADJUSTMENT

PROCEDURES

@

Bias

Current

Adjustment

(1)

(2)

Class

B

Connect

JL15

and

JL12

with

a

jumper.

Parts

adjusted:

RL43

and

RL44

Input:

~

Output:

8Q

load

Adjustment:

Connect

a

digital

voltmeter

between

JJO1

and

JJO2

(for

the

L

channel)

or

between

JJO3

and

JJ04

(for

the

R

channel).

Wait

until

the

voltage

stabilizes

(30-60

seconds),

then

adjust

RL43

or

RL44

so

that

the

voitmeter

reads

14

mV.

Class

A

Parts

adjusted:

RL39

and

RL40

Input:

-

Output:

8Q

load

Adjustment:

|

Connect

a

digital

voltmeter

between

JJO1

and

JJO2

(for

the

L

channel)

or

between

JJO3

and

JJO4

(for

the

R

channel).

Wait

until

the

voltage

stabilizes

(30—60

seconds),

then

adjust

RL43

or

RL44

so

that

the

voltmeter

reads

370

mV.

Shorts

amplifier

input

to

eliminate

noise

pickup

5.

VOLTAGE

CONVERSION

6.

BLOCK

DIAGRAM

@

EUROPEAN

MODEL

ONLY

TAGE

POWER

SUPPLY

To

convert

the

unit

to

a

different

power

source

voltage,

change

the

position

as

illustrated

in

the

drawing

below.

CAUTION

DISCONNECT

POWER

SUPPLY

CORD

FROM

AC

OUTLET

BEFORE

CONVERTING

VOLTAGE.

LOW

VOL

CIRCUIT

SWITCHING

O—“

|]

HEAD

PHONES

SPEAKER

PROTECTION

OuTPUT

HIGH

VOLTAGE

OWER

SUPPLY

E

SPK

SYSTEM

Voltage

Conversion

Chart

&

w

el

=o

a

=

°

I<

Es

>

oO

q a

x

=o

5

oz

a

53

°

aE

3

a

aa

c

s

fo}

aq

>

FLAT

AMP

TONE

AMP

_

N

= =

Ww

WwW

8

o

¢&

&

Ww

>

WwW

~

‘

Z

e

2

=

=)

LU

gy

3

g

a

o

[om

s

>

B

S

@

cS)

2a

2

ot

a

@

VOLTAGE

SELECTOR

x

=|

a

qt

7

N

ph

Ee

nat.

28

[fb

s

a

fo}

oO

Nn

w

We

a

g

2

48

|

Note

on

safety:

Symbol

A\

Fire

or

electrical

shock

hazard.

Only

orignal

parts

z

-

&«

should

be

used

to

replace

any

part

marked

with

symbol

A

.

3

Any

other

component

substitution

(other

than

original

Py

type),

may

increase

risk

of

fire

or

electrical

shock

hazard.

-§

©

©)

o

x

=

*

s

N

}

o

Ess

re)

am

a

re)

s

a

ae

2 2

re

<

zoe

a

ge

of

@

aed

a

ie

2

Pas

5

7.

DIAGRAM

AND

COMPONENT

LOCATIONS

7.1

Filter

Assembly

(PHOO)

Schematic

Diagram

and

Component

Locations

7.3

Voltage

Amp.

Assembly

(P700)

Schematic

Diagram

and

Component

Locations

|

PHOO

|

P700

;

R751

2.76(2W)

er

|

QHO!

~

1/2

cHOS

4.7/25V

R755

2.2

R74

2k

CT

0.47

Pare

on

Ce

O

ov

BK

OL

bo

@_®

721

Law

gh

9

Sea

eees

7.6

ASO

Protector

Assembly

(PNOO)

7.2

Speaker

Switch

Assembly

(PW00)

~

Schematic

Diagram

and

Component

Locations

Schematic

Diagram

and

Component

Locations

5

P¥aQGi-w?

GISOHISSHY

7.5

Loudness

Assembly

(PF00)

Schematic

Diagram

and

Component

Locations

[PFOO

_

couoness

7.7

Test

Point

Assembly

(PJ00)

Td

Schematic

Diagram

and

Component

Locations

ee

O

JJO1

JJOZ

CERTHSSS

HNIO3

xe

WLHAD

P400

ms

ane

sue

.

7.8

Tone

Amp.

Assembly

(PE01)

Schematic

Diagram

and

Component

Locations

me

tae

F

Ectoe,

ae

|

7.10

Pre-Amp.

Assembly

(P400)

Schematic

Diagram

and

Component

Location

>

RS

=

*

.

oer

Saou,

TES

nm

QMOl

~

QM04

|e

+

‘i

=

-—to

|

i

PY

—QMo9

~

OMI2

ov

fey

|

j

404

oe

Hf

8

F.—Ff

toil

,

onl

1

o

fg

1°

Fee

nt

\

ak

33"

a1

i

|ele

ee

2

me

HB

3

i

Ts

es

er

|

a

5

—=C5

3

&

—

——

I

|

I

2

wh

|

:

pS)

|

TUNER

8

sav

|

t

EHR

ae

|

eee

|

pes,

($402)

RES!

RE!

QE52

be

is

270/2WIS

270

(I/2W)

eS!

JESS

:

|

©

°

a

e

Hey

|

|e

|

O+©

|

;

ine

}

7.11

Transistor

Block

Assembly

(P401)

a

°

Schematic

Diagram

and

Component

Locations

O+F+©

7.9

Tone

On-Off

Assembly

(PS00)

Schematic

Diagram

and

Component

Locations

|

_

O+F©

AKSSJHI250_

bik

)

@)

j

O+4F-©

Ra65

220

|

eas,

an

Rags

220!

0

1

©

Oo

L4or

Base

220

|

,

—

;

%

R464

560

7.12

MC

Transistor

Block

Assembly

(PM01)

Schematic

Diagram

and

Component

Locations

12

1

i

SOURCE

t

SOURCE

2-1

2

TAPE

COPY

TAPE

MONITOR

(s403)

(s401)

mM

!

|!

oa

I

8

;

2

9

LJ

'saor

|8

\saoz

|2

1

ae

'

oO

Leo}

©

©)

Us

ed

Big

pe)

QMO!l

~

QM04

QMO9

~

QMI2

QMI3

~

QMI6

QMO05

~

OMO8

[J],

-260

©

HO)

©

733V

MOB

RM

470(6)

5.6K

TUNER

-

1

PHONO

iv,

inane

TVs

AUX

OP

°

—-

Re04

-1.4V

oe

INPUT

SELECTOR

WOOK)

3

CH

12.0

($402)

Race.

hae

0407

$

Rg

—

oO

4

re

O-

_

1

°

|

©

©)

‘

a

4401

oot

tty

|

8

0

i

oot

Pod

|

Fe

4

|

©

(0)

owed

|

:

o

i

Oo

H

aa

|

2

i

©

©)

1402

©

©)

oO

©

©)

|

4403

©

©)

r

9

1

i

0

b-eo

1

oO

1

Rass

220)

©

LL.

bo

i

9

R464

560

o-

S4zi

S422

12

SOURCE

2-1

TAPE

COPY

TAPE

MONITOR

($403)

€

©

Rao!

39K(6)

Rao

[

Cty

o

R40;

©

ports)

&

oz

R.

1OOKIG)

z8

Q403

M24

8.0015,

'CM23

0.0015

Rail

tk

(6)

25.0V

0405

ed

401

Ye

ov

r)

—Wwy——

R408

100K

C423

0.0015

1}-————

R459

220K

1

t

SOURCE

2

$401)

Cell

220/35V

R80D

_Ce0R

/50V

n+

5.k

>

He

C82

220/35V

415

7.10

Pre-Amp.

Assembly

(P400)

Schematic

Diagram

and

Component

Locations

7.11

Transistor

Block

Assembly

(P401)

Schematic

Diagram

and

Component

Locations

7.12,

MC

Transistor

Block

Assembly

(PM01)

Schematic

Diagram

and

Component

Locations

7.13

Head

Phone

Assembly

(PX00)

Schematic

Diagram

and

Component

Locations

EF

Marantz Pm-6a User manual

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