JVC DD-9 A Manuale utente

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MODEL

DD-9

A/B/C/E/J/U

STEREO

CASSETTE

DECK

No.

4198

March

1981

DD-9A/B/C/E/J/U

|

Contents

Page

Features

sy

hn

ge

west

OEE

end

ES

ena

nad

we

alee

%

2

Specifications:

~f

sadeiaclha

woe

aeons

ba

eee

es

3

Controls

and

Connections

...........2

002

ee

eee

4

Main

Parts

Location

........-..

00000

eee

eee

5

Maintenance

.....

2.0...

0.

eee

ee

ee

eee

5

Description

on

New

Technology

..............0-

6

Removal

of

the

Main

Parts

................0005

8

Main

Adjustments.

.........0

0.000

ee ee ee

eee

9

Block

Diagram

(1)

2.0.0.0...

2.

cee

eee

ee

eee

17

Block

Diagram

(2)

1...

0...

ee

es

18

Wiring

Connection

(1)

..............2222000-

19

Wiring

Connection

(2)

.............0000

tees

20

Wiring

Connection

(3)...

0.2.0.0...

0

eee

ee

eee

21

Standard

Voltage

Value

............0000

eee

22

Integrant

Circuits...

ee

ee

ee

23

Standard

Schematic

Diagram

(Main

Amp.

Circuit)

...

25

Standard

Schametic

Diagram

(Computer

Circuit)

....

26

Standard

Schematic

Diagram

(Mecha.

Control

Circuit).

27

Features

=

2-motor

full-logic

mechanism

with

quartz-locked

pulse-

servo

D.D.

motor

©

A

quartz-locked

pulse-servo

D.D.

motor

newly

developed

for

capstan

drive

and

a

DC

motor

for

reel

drive

©

Low

wow/flutter

(WRMS

0.019%)

©

TIMER

STANDBY

mechanism

(with

maloperation

protection)

©

AUTO-REWIND

mechanism

©

Remote

control

terminal

provided

(R-50E

optional)

@

Built-in

computer

B.E.S.T.

tuning

system

for

automatic

adjustment

of

Bias,

Equalization

and

Sensitivity

of

tape

=

Metal

tape

compatible

®

Three-head

system

permitting

monitoring

while

record-

ing

is

being

made

©

X-cut

SA

(Sen-Alloy)

combination

record/playback

head

©

2-gap

SA

erase

head

No.

4198

Page

Standard

Schematic

Diagram

(Fl

Circuit,

DD

Motor

Circuit)

..........00.0.

28

Enclosure

Assembly

and

Electrical

Parts

..........

29

Mechanical

Component

Parts

............2200%

30

Enclosure

Assembly

and

Electrical

Parts

List

.......

31

Mechanical

Component

Parts

List

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

34

Main

Amp.

P.W.

Board

Parts

List...............

36

Main

Amp.

P.W.

Board

Parts.

...........000005

39

Computer

P.W.

Board

Parts

..........-..00005

40

Computer

P.W.

Board

Parts

List

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

41

Mecha.

Control

P.W.

Board

Parts,

Parts

List........

44

Display

P.W.

Board

Parts,

Parts

List

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

46

DD

Motor

Circuit

Parts

List

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

2.00004

47

Other

P.W.

Board

Parts

...

0.0...

0000

eee

eee

48

Other

P.W.

Board

Parts

List

..............200.

49

Packing,

Packing

Material

Parts

List

........

Back

cover

ACCESSOFIES:

eh

-8

5S

5,

Be

RES

eS

Back

cover

®

2-color

FL

digital

meter

(PEAK/VU

selectable)

with

peak

hold

function

®

DC

configured

record/playback

amplifier

™

Electronic

control

for

recording

level

adjustment

=

Equipped

with

ANRS/DOLBY

B

and

DOLBY

C

NR

moise

reduction

systems.

@

Timer

standby

capability

for

automatic

recording

or

playback

using

an

AC

timer

®

Headphones

in

connection

with

slide

system

output

level

control

m

Record

muting

(REC

MUTE)

mechanism

(with

operation

indicator

LED)

®

New

slim

design

with

push

button

switches

Specifications

Type

:

Component

stereo

cassette

deck

Track

system

:

4-track,

2-channel

Tape

speed

:

1-7/8

inch/sec

(4.8

cm/sec)

Frequency

response

:

(—20

VU

recording)

Metal

tape

o4

;

15—20,000

Hz

25—18,000

Hz

(+

3

dB)

SA/Chrome

tape*2;

15—20,000

Hz

25—18,000

Hz

(+

3

dB)

SF/Normal

tape

*3;

15—19,000

Hz

(0

VU

recording)

Metal

tape

SA/Chrome

tape

SF/Normal

tape

25—17,000

Hz

(+

3

dB)

;

25—12,500

Hz

(+

3

dB)

;

25—8,000

Hz

(+

3

dB)

;

25—8,000

Hz

(+

3

dB)

Frequency

response

when

using

the

computer

B.E.S.T.

tuning

system:

(—20

VU

recording)

Metal

tape

SA/Chrome

tape

SF/Normal

tape

Note:

“1

;

40—12,500

Hz

(+

1

dB)

;

40—12,500

Hz

(+

1

dB)

;

40—12,500

Hz

(+

1

dB)

Those

values

are

almost

the

same

for

all

types

of

tapes

when

the

com-

puter

B.E.S.T.

tuning

system

is

used.

JVC

ME

or

Equivalent

*2

.....

TDK

SA

or

Equivalent

Lic

ea

S/N

ratio

NR

effect

Wow

and

flutter

Crosstalk

Harmonic

distortion:

MAXELL

UD

or

Equivalent

;

60

dB

(DIN

45

500

weighted,

Metal

tape)

;

5

dB

at

1

kHz,

10

dB

at

5

Cae

{lANRS/Dolby

B

NR)

15

dB

at

500

Hz

20

dB

at

1

kHz

_f

(Dolby

©

NR)

:

0.019%

(WRMS)

with

JVC

test

tape

0.055%

(DIN

45500)

with

MAXELL

UD

tape

:

65

dB

(1

kHz)

K3;

0.4%,

THD;

1.0%

(Metal

tape,

1

kHz,

0

VU)

Bias

Erasure

Heads

Motors

Fast

forward

time

Rewind

time

Semiconductors

Input

terminals

Mic

jack

x

2

Input

jack

x

2

Output

terminals

Output

jack

x

2

Phone

jack

x

1

DD-9A/B/C/E/J/U

:

AC

bias

:

AC

erasure

:

3

heads

SEN

ALLOY

head

for

recording,

SEN

ALLOY

X-cut

type

for

play-

back

and

two-gap

SEN

ALLOY

head

for

erasure

:

Quartz-lock

pulse

servo

DD

motor

(for

Capstan)

DC

motor

(for

Reel}

:

85

sec

or

less

with

C-60

cassette

:

85

sec

or

less

with

C-60

cassette

:

45

ICs,

140

transistors,

88

diodes,

2

hall

(C,

18

LEDs

Max.

sensitivity;

0.2

mV

(—72

dBs)

Matching

impedance;

600

§2~

10

kQ2

Min.

input

level;

80

mV

(—20

dBs)

Input

impedance;

100

k{2

;

Output

level;

O

~

500

mV

Output

impedance;

5

kQ2

;

Output

level;

O

~

0.6

mW/8

G2

Matching

impedance;

8

Q)

~

1

kQ

Remote

control

socket:

8

pin

DIN

type

(for

R-50E

optional)

Power

requirement

Power

consumption

Dimensions

Weight

:

AC

240

V,

50

Hz

(DD-9A)

AC

120

V,

50

Hz

(DD-9C/J)

AC

240/220/120

V,

50/60

Hz

(DD-9B/E)

AC

240/220/120/100

V,

50/60

Hz

(DD-9U)

>

40

W

>

17-3/4"

(450

mm)

W

12-3/4"

(325

mm)

D

4-3/8”

(110

mm)

H

(with

feet,

buttons,

switches)

:

18.5

Ibs

(8.4

kg)

Design

and

specifications

subject

to

change

without

notice.

No.

4198

DD-9A/B/C/E/J/U

Controls

and

Connections

aa

ie

$e

Fig.

1

30

e

VOLTAGE

SELECT

nfs

REMOTE

CONTROL

—

ROWER

SOURCE

(

m

UOLRY

AND

ONE

DOUBLED

SUMBOL

ARI

TRADEMARKS

GF

DALEY

At

RATORI'S

ca

2

Ainianantenintinmmanntr

eT

itferntmeenttnntin

te

33

Fig.

2

1.

POWER

switch

2.

TIMER

STANDBY

switch

3.

FL

meter

4.

COMPUTER

B.E.S.T.

TUNING

SYSTEM

indicators

5.

DOLBY

B/ANRS

and

DOLBY

C

indicators

6.

TAPE

(METAL)

indicator

7.

MONITOR

(SOURCE,

TAPE)

indicator

8.

PRESET

indicator

9.

ERROR

indicator

10.

Cassette

holder

11.

Electronic

counter/Reset

button

12.

Quartz

lock

indicator

13.

AUTO

REWIND

switches

14.

OUTPUT

LEVEL

knob

15.

PHONES

jack

(Headphone)

16.

MIC

jacks

(Microphone)

17.

NRswitches

18.

TAPE

SELECT

switches

19.

COMPUTER

START

button

20.

COMPUTER

PRESET

button

21.

MONITOR

button

No.

4198

19

20

21

22

23

24

31

ereouENEY

©)

J

25

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

33.

34.

35.

36.

25

26

27

28

WANUFACTURED

8Y

3)

CTOR

CoMPamy

OF

IAPLN

LTH

FORTO

APRN

AD]

IN

PAN,

en

METER

switch

(VU

@

PEAK)

INPUT

BALANCE

knob

INPUT

LEVEL

buttons

(DOWN

«

UP)

EJECT

button

COUNTER/STOP

WATCH

select

switch

MEMORY

switch

REC

MUTE

button

Cassette

operation

buttons

<<)

REW

(Rewind)

button

with

indicator

>

PLAY

button

with

indicator

>>

FF

(fast-forward)

button

with

indicator

fe)

REC

(Recording)

button

with

indicator

.

STOP

button

|

PAUSE

button

with

indicator

REMOTE

CONTROL

socket

FREQUENCY

select

switch

(50

Hz/60

Hz)

MPX

filter

switch

Voltage

select

switch

(DD-9B/E/U)

LINE

IN

(REC)

terminals

LINE

OUT

(PLAY)

terminals

Power

cord

|

i

Main

Parts

Location

Maintenance

To

get

long,

trouble-free

service,

maintenance

is

important.

Do

not

forget

cleaning

and

demagnetizing.

Cleaning

After

long

use,

the

heads

and

tape

part

—

capstan,

pinch

roller,

etc.

—

will

become

dirty

with

dust

or

magnetic

particles.

Dirty

heads

cause

imperfect

erasing

or

high

fre-

quency

drop-off.

A

dirty

capstan

and

pinch

roller

will

cause

unstable

tape

speed,

leading

to

increased

wow

and

flutter.

Always

keep

them

clean

by

following

the

procedure

below.

1.

Heads

1)

Push

Eject

button

to

open

the

cassette

holder.

2)

Use

the

head

cleaning

stick

provided

to

wipe

the

surface

where

the

tape

comes

into

contact

with

the

head.

(It

is

effective

to

moisten

the

cotton

with

alcohol.)

2.

Pinch

roller

and

capstan

Do

the

samemethod

as

heads.

3.

Cabinet

When

the

cabinet

becomes

dirty,

wipe

it

with

a

soft

cloth

soaked

with

a

neutral

cleaning

solution

of

a

polishing

cloth.

*

Do

not

use

thinner

or

benzine.

|

DD-9A/B/C/E/J/U

Power

switch

Pin

jack

ass‘y

Computer

P.W.B.

ass’y

Power

supply

P.W.B.

ass’y

Power

transformer

Front

plate

ass’y

F.L.

P.W.B.

ass’y

Gear-oiled

damper

Mechanical

assembly

Mecha.

control

P.W.B.

ass’y

Auto

stop

pulley

POSEN

OAPWN

>

_—

—

Mechanical

parts

are

the

same

as

location

of

model

DD-7,

Please

refer

to

the

service

manual

of

DD-7A/B/C/E/J/U

(No.

4195

—

page

3).

Demagnetizing

The

heads

are

made

from

a

material

resistant

to

magneti-

zation,

but

after

long

use

they

may

become

magnetized.

A

magnet

brought

into

their

vicinity

can

magnetize

the

heads,

causing

excess

noise.

If

noise

seems

to

have

increased,

demagnetize

the

heads

with

a

head

demagnetizer

through

the

following

procedure.

1.

Turn

the

POWER

switch

OFF.

2.

Wrap

the

tip

of

the

demagnetizer

with

vinyl

tape

or

soft

cloth

so

as

not

to

damage

the

head

surface.

Switch

on

the

demagnetizer

and

bring

it

close

to

the

head.

3.

Move

the

tip

of

the

demagnetizer

slowly

first

to

the

left

and

right,

then

up

and

down

in

front

of

the

head.

Gradually

move

it

away

from

the

head

and

switch

it

off

at

a

distance

of

more

than

30

cm

(12”).

4.

The

erase

head

need

not

be

demagnetized.

The

capstan

shaft

and

tape

guide

should

be

demagnetized

in

the

same

way

as

the

record/playback

head.

Do

not

bring

a

magnetized

metallic

object

(a

screwdriver,

for

example)

near

the

head

as

this

will

increase

noise.

No.

4198

|

|

:

DD-9A/B/C/E/J/U

|

Description

on

New

Technology

=

DD

(Direct

Drive)

Mechanism

Equipped

with

Newly

=

Memory

Stop

and

Auto-rewind

Developed

Quartz-locked

Pulse

Servo

DD

Motor

A

direct

drive

system

is

employed

in

which

the

motor

shaft

itself

is

the

capstan

shaft,

without

the

rotation

transmitting

members

(idlers,

pulleys,

etc.)

which

cause

unstable

tape

rotation.

Our

newly

developed

pulse

servo

motor

is

employed

for

this

driving

power

source.

The

motor’s

construction

is

free

from

thrust

unbalance

or

cogging,

thus

permitting

a

high

flywheel

effect.

For

precise

rotation,

this

motor

uses

a

full-circumference

integration

type

FG

detection

system

and

an

auto-

balance

circuit

which

reduces

torque

unbalance.

Thus,

the

motor

drives

the

tape

transport

mechanism

with

smooth

rotation.

Further,

the

employment

of

the

quartz

lock

system

results

in

exceedingly

small

fluctuation

of

speed.

For

detailed

information,

refer

to

service

manual

(No.

4195)for

DD-7.

Three-head

System

with

X-cut

SA

Record/Playback

Combination

Head

The

record

head

uses

a

4u-gap

SA

head

for

improved

recording

sensitivity

and

a

reduced

distortion

rate.

The

playback

head

uses

an

X-cut

1p-gap

SA

head

for

reduced

low-frequency

contour

effect.

These

two

heads

are

com-

bined.

The

erase

head

employs

a

2-gap

SA

head

excellent

in

erasure

efficiency.

For

more

details,

refer

to

page

5

in

service

manual

(No.

4186)

for

KD-A77.

All-stage

DC

Configurated

Amplifiers

The

playback

head

and

the

equalizer

amplifier

are

direct-

ly

coupled.

Since

all

stages

between

amplifiers

are

DC

configured,

the

number

of

the

capacitors

which

adversely

affect

sound

quality,

is

decreased.

In

addition,

the

+2

V

constant

voltage

source

and

the

differential

amplifier

enable

stable

high

linearity

and

wide-band

reproduction.

Dot-matrix

Type

2-color

FL

(fluorescent

tube)

Peak

Level

Meter

The

2-color

fluorescent

indicator

tube

which

is

longest

at

135

mm

among

cassette

decks.

The

R

and

L

indicator

bars

are

independent

of

each

other.

Each

bar

is

divided

into

18

segments,

each

further

into

20

dots.

So,

the

level

can

be

monitored

with

a

feeling

of

a

consecutive

bar

graph.

This

meter

is

provided

with

a

peak-hold

function,

thus

facilitating

level

setting.

Moreover,

it

has

a

selection

switch

between

the

PEAK

and

VU

meters.

No.

4198

By

joint

use

of

the

MEMORY

switch,

AUTO

REWIND

switch

(PLAY/STOP)

and

the

electronic

counter,

the

following

operations

are

possible:

Continuous

tune

repeat

between

the

beginning

of

the

tape

and

the

point

of

the

tape

at

which

the

MEMORY

switch

is

pressed;

tune

repeat

between

‘000’

to

which

the

counter

is

reset

by

the

RESET

switch

and

the

point

of

the

tape

at

which

the

MEMORY

switch

is

pressed

or

between

this

pcint

of

the

tape

and

the

end

of

the

tape.

Needless

to

say,

the

conventional

functions

can

be

per-

formed

by

ON-OFF

operation

of

the

MEMORY

switch

or

the

AUTO-REWIND

switch

(ON/OFF)

singly.

Electronic

Volume

Control

Motor

rotation

is

controlled

by

switching

the

polarity

by

IC

so

that

the

input

volume

can

be

set

by

one-touch

recording

level

UP-DOWN

operation.

The

set

recording

tevel

is

indicated

by

the

needle

which

moves

in

response

to

the

control

motor.

Newly

Developed

Computer

B.E.S.T.

(Bias

Equalizer

Sensitivity

Tuning)

System

3-head

Tape

Deck

This

system

was

developed

for

3-head

tape

deck

utilliz-

ing

the

fundamental

concept

of

the

previous

versions

KD-A8

and

KD-A66.

With

stress

laid

upon

MOL

balance,

the

bias

leve!

is

set

at

the

average

of

the

optimum

bias

points

which

are

detected

at

16

steps

each

for

R

and

L

channels.

To

control

the

medium-frequency

response,

a

process

to

make

the

4

kHz/1

kHz

response

flat

is

provided.

This

response

is

set

at

the

average

between

those

R

and

L

values

which

are

taken

each

at

8

steps.

The

tape

sensitivity

is

set

at

an

average

of

those

R

and

L

values

which

are

taken

at

16

steps

each.

The

high-

frequency

equalization

level

is

adjusted

at

16

steps

each

for

R

and

L

channels,

independently.

In

addition,

since

the

A/D

conversion

system

of

the

detection

signal

has

been

changed

from

the

peak-hold

type

to

the

soft

peak-hold

type,

a

momentary

pulse

due

to

noise

is

not

detected.

Therefore,

this

system

is

designed

to

hold

nothing

but

continuous

sigrals.

Dolby*

C-Type

Noise

Reduction

System:

Noise

is

reduced

and

MOL

increased

dramatically.

The

Dolby

C-type

closely

resembles

the

B-type

in

operation,

the

system

compatible

with

ANRS,

yet

offers

even

better

performance

and

more

distinctive

features.

Namely:

®

\|t

provides

about

20

dB

above

1

kHz,

and

15

dB

even

at

500

Hz

of

noise

reduction.

®

At

10

kHz

(at

OVU

recording),

it

improves

MOL

by

4

dB

maximum.

®

It

is

immune

to

undesirable

side

effects,

such

as

modu-

lation

noise

and

breathing.

®

Finally,

it

is

tolerant

of

noise

reduction

encode/decode

errors.

Level

matching

is

not

critical.

(*

Dolby

is

a

trademark

of

Dolby

Laboratories,

Inc.)

The

basis

of

C-type

noise

reduction

Dolby

C

noise

reduction

solves

the

problem

of

achieving

a

large

amount

of

compression

and

expansion

without

introducing

undesirable

side

effects

by

the

use

of

two

pro-

cessing

stages

in

series,

each

supplying

10

dB

of

compression

during

recording

and

of

expansion

during

playback.

These

circuits

operate

at

independent

levels.

One,

identified

as

the

high-level

stage

in

Figure

B,

is

sensitive

to

signals

at

about

the

same

levels

as

Dolby

B-type

noise

reduction,

while

the

other,

the

low-level

stage,

operates

on

signals

of

somewhat

lower

level.

Because

the

two

stages

operate

in

tandem

with

each

other,

their

effect

is

to

multiply

the

signals

(or

add

and

subtract

in

dB’s),

so

that

a

total

of

20

dB

of

compression

and

expansion,

and

thus

of

noise

reduction,

is

accomplished.

Yet

simultaneously,

at

no

time

is

the

signal

subject

to

the

vagaries

of

a

single

compression

or

expansion

action

of

20

dB.

In

other

words,

the

tandem

two-level,

two-stage

con-

figuration

provides

a

much

more

accurate

control

of

the

signal

than

a

single

compander

circuit

would

be

able

to

achieve.

Two

conventional

Dolby

B

IC

circuits

are

used

ina

modified

way

in

C-type

noise

reduction

to

carry

out

the

two-level,

two-stage

scheme.

Thus

a

desirable

side

benefit

of

C-type

noise

reduction

is

that

it

can

be

executed

from

the

begin-

ning

with

readily

available

and

economical

parts

(the

development

of

a

dedicated

Dolby

C

integrated

circuit

in

the

future

would,

however,

simplify

incorporating

C-type

NR

in

products).

Furthermore,

one

of

the

two

stages

can

be

easily

configured

to

provide

the

B-type

characteristic

at

the

push

of

a

switch,

so

cassette

decks

incorporating

C-type

noise

reduction

can

be

economically

equipped

with

Dolby

B

NR

as

well

for

perfect

compatibility

with

existing

B-type

recordings.

a

eae

ee

et

:

MOL

Improved

by

3

Reference

Level

(160nwb/m)

——-+=

about

4dB

(10kHz)

SEP

apo

pe

tots

Dolby*C

ON

=P“

Noise

Reduction

OFF

4-

:

i

PSE

SS ee

eg

ON

Kei

=

S/N

Improved

by

about

20dB=--}—

_-

(ikHz

and

above)

=

Eieaehattwalis

i

Output

Level

(dB)

BAS

reenrears

TARe

FSI

ARS

Noise

Reduction

OFF

Hi

Tay

eae

saith

ae

+)

ANRS/Dolby*B

ON

i

edt

t

I

se

|

SIN

Improved!”

{

{Dolby*c

ONT

E

“--H

by

about

15dB

5

-

20

50

100

200

500

1000

2000

5000

10000

20000

Frequency

(Hz)

Dolby*

C

Improvement

Other

developments

In

addition

to

two-level

processing,

Dolby

C-type

noise

reduction

incorporates

a

number

of

further

innovations.

Two

of

these,

shown

in

Figure

B

as

anti-saturation

and

spectral

skewing

networks,

are

carefully

calculated

fre-

quency

response

modifications

introduced

in

the

encoding

(record)

process

and

reciprocally

compensated

for

in

the

decode

(playback)

process.

Their

purpose

is

two-fold:

to

further

guard

against

audible

side

effects,

and

to

ensure

the

practicality

of

the

system

in

day-to-day

consumer

use.

The

specific

benefits

of

these

innovations

include

the

reduction

of

encode-decode

errors

and

a

reduction

of

upper-middle

and

high

frequency

tape

saturation

and

its

side

effects,

such

as

high

frequency

losses

and

_

inter-

modulation

distortion.

Together

with

the

two-level,

two-

stage

configuration,

these

new

developments

result

in

a

20

dB

noise

reduction

system

at

least

as

free

of

side

effects

as

the

10

dB

B-type

system,

and

one

which

is

just

as

practi-

cal

in

day-to-day

use.

—~6-A—

Tee

TTT

TTT

ce

TTT

BATT

HTT

LTT

CHAE

a

TTT

Fig.

A

Low-level

encoding

frequency

response

The

effect

also

extends

about

two

octaves

lower

with

C-

These

curves,

showing

the

maximum

low-level

boost

im-

parted

by

both

C-type

and

B-type

noise

reduction

in

the

type

noise

reduction

to

maintain

subjectively

uniform

noise

level

across

the

spectrum.

Processing

at

very

low

frequencies

absence

of

high

frequency

signals,

illustrate

some

of

the

is

not

required

with

either

system

because

low

frequency

noise

similarities

and

differences

between

the

two

systems.

Dolby

C

noise

reduction

imparts

more

boost

in

recording

and

more

cut

in

playback,

thus

providing

more

noise

reduction.

in

properly

engineered

cassette

insignificant

is

recorders.

TO

RECORDING

AMPLIFIER

IC2

SIDE*CHAIN

OF

LOW:

LEVEL

STAGE

4

|

J

|

|

|

A

Se

ee

---

|

L

DOLBY

C-TYPE

ENCODER

ANTI-

SATURATION

NETWORK

HIGH

*LEVEL

STAGE

SIDE-CHAIN

OF

ae

SPECTRAL

SKEWING

FROM

INPUT

STAGES

KB

i)

a

—

=)

oO

SPECTRAL

SKEWING

4

|

STAGE

SIDE+

CHAIN

OF

HIGH?

LEVEL

eles

SATURATION!

NETWORK

5

|

SIDE+

CHAIN

OF

LOW-LEVEL

STAGE

ae

x<

oc

Sui

aa

ter

par

gay

as

xt

oy

fe

DOLBY

C-TYPE

DECODER

Dolby

C-type

NR

block

diagram

Fig.

B

—6-B—

DD-9A/B/C/E/J/U

Features

of

New

B.E.S.T.

System

ee,

®

Bias

Level

Setting

System

with

MOL

Balance

Taken

into

=

Comparison

Table

between

KD-A66

and

DD-9

Consideration

cree

With

an

8

kHz

variable

normal

or

chrome

tape,

the

dif-

pia

pee

ference

in

bias

level

between

MML

(333

Hz)

and

MOL

eae

Bias

level

(B)

Coincident

point

of

7

kHz

and

1

kHz

The

bias

level

is

lowered

by

A

dB

due

to

the

(10

kHz)

is

set

to

12

dB,

while

with

a

metal

tape,

it

is

set

(2)

8

steps

bias

current

characteristics,

as

the

MOL

bal-

to

around

8

dB.

The

MOL

balance

is

thereby

stabilized.

penne

||

Detection

at

R

channel

ance

is

considered.

4

a

peak

point?

eee

:

Wes

16

steps

=

High-accuracy

Bias,

Equalization

and

Sensitivity

Level

—

Average

value

between

R

and

L

channels

Is

there

the

Setting

System

set

bias

point?

eae

:

Se

;

a

Medium-frequency

Coincident

point

of

4

kHz

and

1

kHz

2

Rh

ee

The

accuracies

of

bias,

sensitivity,

medium

and

high

fre-

quency

equalization

levels

are

greatly

improved

through

average

calculation

of

reading

error.

8

steps

Average

value

between

R

and

L

channels

Coincident

point

of

12.5

kHz

and

1

kHz](1)

Coincident

point

of

12.5

kHz

and

1

kHz

(2)

8

steps

(2)

16

steps

Detection

at

R

and

L

channels

Recording

is

performed

3

times

at

each

step.

(3)

Average

value

between

R

and

L

channels

Equalization

level

{medium

frequency)

adjustment

equalization

level

(EQ

M)

FIRST

BIAS

ds

the

response

at

1

kHz/4

kHz

flat?

NO.

High-frequency

equalization

level

(EQ

H)

=

Second

Bias

System

Recording/playback

With

a

special

tape,

the

respective

levels

are

readjusted

sensitivity

adjustment

by

this

system,

thus

their

accuracies

are

assured.

(1)

(1)

Coincident

point

of

recording

and

playback

at

1

kHz

(2)

16

steps

(3)

Average

value

between

R

and

L

channels

Coincident

point

of

recording

and

playback

at

1

kHz

(2)

8steps

(3)

Detection

at

R

channel

About

25

sec

Tape

sensitivity

level

(S)

Are

the

recording

and

playback

sensitivities

equal

with

each

other?

NO

=

4-bit

1-chip

2k

ROM

Microcomputer

Equalization

level

(high

frequency)

adjustment

Required

time

About

30

sec

(This

time

differs

slightly

according

to

the

tape

used.)

4-bit

1-chip

2k

ROM

4-bit

1-chip

2k

ROM

1s

the

response

at

1

kH2/12.5

kHz

flat

NO

Set

B.E.S.T.

j

]

a

Indications

PRESET/ERROR,

RUN/READY

B,

EQM,

S.EQH,

PRESET,

ERROR

Memory

Not

provided

Temporary

memory

1s

the

response

NO

.

atl

HL

2:

RHE

te

a

A/D

conversion

Peak-hold

type

Soft

peak-hold

type

4

Equalization

level

(medium

frequency)

adjustment

Grant

Bias

level

setting

Bias

level

setting

L

channel

7

EHO

LHe

INO

—

‘

channel

at

;

oS

Zz

BkH2

ne

lat?

oi

'

a

nil

|

fe

Recording/playback

sensitivity

MOL

balance

nas

aie

T

aa

;

;

|

adjustment

‘ '

. .

.

|

|

|

Phy

ae

non

ips

2

With

the

linearity

characteristics

of

the

tape

and

the

fre-

|

MOL

difference

annEaI

BESIABOLEEE

cea

rl

ty

a

:

r .

ot

eye

a

¢

quency

components

of

the

input

signals

taken

into

con-

REC

ON

ias

level

detectin

i

Are

the

i

‘ :

R

channel

Bias

level

detecting

point

L

channel

Bias

level

detecting

point

8

Fecording

and

playback.

No

=

sideration

to

record

musical

signals

at

good

balance,

the

315

Hz

10

kHz

”n

«

|

Spon

emnert

difference

between

the

low-frequency

(315

Hz,

K3

:

3%)

i

MOL

and

high-frequency

(10

kHz)

saturation

MOL

(or

Medien

frequency,

eqilalization

Tape

sensitivity

level

setting

i

.

:

3s

id

(

)

{

lel

setting

Equalization

Jevel

(high

SOL)

is

set

to

12

dB

on

normal

tapes

and

8

dB

on

high-

|

frequency)

adjustment

\

performance

tapes

such

as

metal

tapes,

etc.

Output

es

Lg

ee

sinned

ina

ico

Thus,

the

maximum

recording

level

is

determined

and

& 6

(ket,

T

1

kHz/12.5

a

i j

i

i

{hie

cial

le

nll

cele

ul

|

allele

fiat?

2

oe

the

bias

current

is

set

with

a

MOL

difference.

A

dB

;

SS

Ce

eee

eas

sae

4

feieorer

Practically,

a

signal

of

8

kHz

is

recorded

based

upon

the

I

Medium-frequency

equalization’?

(Reference

level}

Tape

sensitivity

level

Set

B.E.S.T.

?

; : ,

level

detecting

point

detecting

point

data

of

various

tapes

and

the

MOL

balance

is

determined

8

kHz

j

é

na

NA

!

by

the

bias

current

characteristics

for

this

signal.

Bias

current

I

:

\

High-frequency

equalization

level

setting

High-frequency

equalization

level

setting

R

chinnel

L

channet

REW

on

12.5

kHz

tie

Fig

5

Fig

6

eT}

ero

A.

CHANNEL

©

1

2

3

4

5

6

bs

J

*

UL

CHANNEL

©

1

2

STOP

L

sTop

Returns

qsthe

start

position

“a

R-ch

high-frequency

equalization

“<

L-ch

high-frequency

equalization.

level

detecting

point

level

detecting

point

REWIND

REWIND

REWIND

Fig.

4

No.

4198

Removal

of

the

Main

Parts

/b-@

Main

amp.

P.W.B.

assy

Mechanical

ass’y

Bracket

Fig.

7

No.

4198

|

DD-9A/B/C/E/J/U

Observe

care

in

handling

the

parts

since

the

parts

are

small

in

size

and

the

distance

between

them

are

short

due

to

a

deck

design

aimed

mainly

at

compactness

and

high

perfor-

mance.

(Remove

in

the

order

of

steps

1,

2,

3,

.....

)

Enclosure

assembly

parts

1.

Cassette

door

To

open

the

cassette

door,

push

on

the

eject

button.

Slide

off

the

cassette

door

upwards.

2.

Top

cover

Remove

5

screws

(a)

fastening

the

top

cover

(left

and

right

.....

2

screws

on

each

and

a

screw

on

rear

center).

3.

Bottom

cover

(1)

Remove

3

screws

(2)

(SDSP3008R)

and

a

washer

(3)

(WNS4000S).

—

These

screws

are

fastened

with

the

front

plate

ass’y.

(2)

Remove

5

screws

fastening

the

bottom

cover.

4.

Front

plate

assembly

Remove

5

screws

(5)

fastening

the

front

plate

upwards.

—

Enclosed

2

screws

for

mechanical

assembly.

Electrical

parts

When

removing

the

wires

from

wire

clamp

(QHX2075-001),

cut

off

its

clamp.

(This

clamp

cannot

be

used

again,

then

apply

a

new

clamp.)

1.

Remove

2

screws(6)

fastening

the

computer

P.W.

board.

Open

its

P.W.

board

from

left

side.

2.

Main

amp

P.W.B.

ass’y

(1)

Remove

4

screws

fastening

the

main

amp

P.W.

board

on

the

bottom

side.

(2)

Remove

3

screws

(8)

fastening

the

switches

on

the

front

side.

(3)

Remove

a

screw(9)

fastening

the

bracket

of

the

com-

puter

P.W.

board

on

the

right

side.

(4)

Pull

off

its

P.W.

board

to

rear

low

side.

3.

Level

indicator

P.W.B.

ass’y

(1)

Remove

2

screws

(10)

fastening

its

P.W.

board.

(2)

Remove

a

screw

(16)

fastening

the

bracket.

4.

Counter

P.W.B.

ass’y

Remove

a

screw

side.

fastening

its

P.W.

board

on

the

rigjt

5.

Power

supply

P.W.B.

ass’y

Remove

4

screws

©)

and

lugs

(3)

fastening

the

power

supply

P.W.B.

6.

Electronic

volume

VR

(1)

Remove

the

front

plate

assembly.

(2)

Remove

the

level

indicator

P.W.

board

ass‘y.

(3)

Remove

the

rope.

(4)

Remove

the

pulley.

(5)

Remove

the

computer

P.W.

board

ass’y.

(6)

Unsolder

3

wires

of

V.R.

board.

(7)

Remove

a

nut

and

a

washer

of

shaft.

(8)

Unsolder

the

V.R.

terminals.

7.

Switches

(Reset,

Memory,

etc.)

(1)

Remove

the

front

plate

assembly.

(2)

Remove

each

knob.

(3)

Remove

the

counter

belt.

(4)

Remove

a

screw

fastening

the

bracket

of

the

pulley.

(5)

Remove

2

screws

fastening

the

counter

P.W.

board.

(6)

Remove

5

screws

fastening

the

switches.

(7)

Pull

off

the

switch

P.W.B.

ass‘y

to

rear

side.

g

Volume

_-6GN,

motor

Front

bracket

?

~

A)

(left)

:

P

s

s

Pulley

aS}

Pulley

&

©

Washer

-

6

Nut

Rope

Counter

“le

display

knob

Fig.

8

Mechanical

assembly

(When

removing

the

front

plate

ass’y,

remove

2

screws

fastening

the

mechanical

assembly

upwards.)

1.

Remove

4

screws

(12)

(left

and

right

.....

2

screws

on

each)

fastening

the

mecha.

assembly

to

the

chassis.

2.

Remove

2

screws

43)

fastening

the

gear-oiled

damper

to

the

chassis,

3.

Remove

a

screw

fastening

the

arm

of

the

gear-oiled

damper.

(When

removing

the

cassette

holder,

to

remove

the

left

bracket,

remove

2

screws

fastening

its

bracket.)

4.

Remove

6

connectors

on

the

mecha.

control

P.W.

board.

5.

Open

the

vinyl

wire

clamp

for

head

wires

on

the

chassis

(bottom

side).

6.

Remove

the

counter

belt.

Mechanical

parts

Mechanical

parts

are

the

same

as

removal

of

model

DD-7.

Please

refer

to

the

service

manual

of

DD-7A/8/C/E/J/U

(No.

4195,

page

10).