Telefunken Magnetofon 77 User Manual

More

Than

Just

Stereo -Magnetophon

77

358

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KEN

MORE

THAN

JUST STEREO

-

MAGNETOPHON

77

Illustration

1:

Rotating

tape

guide

roller in

Magnetophon77.

The

latest

polls,

conducted

with

the

purpose

of

determining

"the

typical

tape

recorder

buyer",

show

a

very

interesting

result.

According

to the findings

of the

poll

there

are

two

basic

groups

of

people

who

buy

tape

recorders.

1. The

«user",·

who

shows no personal

initiative

with

his machine

but

uses it

only

for

recording

any

acoustic

entertainment

offered.

That

his

ent-

husiasm

for

the

tape

recorder

rapidly

wanes,

is

substantiated

by

the

fact

that

he

generally

buys

only

two

or

three

tapes.

Due

to this lack

of

keenness,

the

fact

that

he

owns a tape

recorder

can

hardly

be

considered

as

having

an

exemplary

effect

among

his circle of

acquaintances.

2.

The

tape

enthusiast,

sound

collector,

tape

corres-

pondent,

amateur,

player,

do-it-yourself

man,

call

him

what

you

will.

This

is the

man

who uses

his

tape

recorder

to the

fullest

possible

extent

and

elevates it

from a primitive

record

keeping

machine to a

highly

sensitive

instrument

with

boundless

possibilities.

This

is the

type

of

man

who

exchanges tapes

with

his friends,· dubs

tapes

Jorslideor.home

movieprogrammes,

makes

trick

and

playback

recordings,

records

complete

plays

and

reports:

keeps an

acoustic

diary

on his

children

from

the

day

they

are

born,

mixes,

trans-'

cribcs

and

cuts.

There

were

contradictory

opinions

regarding

the

proportionate

size of these

two

groups.

Pessimists

estimated

the

proportion

of

people

belonging

to

group

2 in

the

Federal

Republic

of

Germany

at

10%.

Then,

the

TELEFUNKEN

Magnetophon

76

fourtrack

tape

recorder

appeared

on

the

scene

and

immediately

started

on a

triumphal

progress

which,

for

home

tape

recorders,

is

outstanding.

Above

all,

the

possibility,

when

playing

back one track, of

being

able to

hear

in

perfect

synchronization

a

recording

made

previously

on

another

track,

proved

to be

ideally

suited

to

so

many

purposes -dubb-

ing,

playback

recordings,

learning

foreign languages

-

that

the

development

engineers .

adopted

the

Magnetophon

76 as a basis

from

which to

work

on

the

creation

of a

stereophonic

parallel

type,

the

Magnetophon

77.

The

idea

was to

retain

the

versa-

tility

of the

monaural

machine in

the

stereo

model

and,

if possible, to

extend

this

versatility

still

further.

The

degree of success achieved in

this

venture

can be seen here.

If

one looks

at

the forebears of the

present

models

Magneto

phon

75, 76

and

77, one sees

from

the

whole

series,

starting

with

the single-speed

Magneto-

phon

65

and

going

on

via

the

two-speed

Magneto-

phon

65 S

and

the ensuing

Magnetophon

65 X to

the

·present

Magnetophon

75,

with

its

improved

technical

concept

yet

practically

unchanged

outer

appearance,

that

there

is such a

thing

as ageless

design.

Further,

and

this is far

more

important

to

the

buyer,

one sees

that

the

retention

of a

proven

mechanical

construction

which enables

more

than

200,000 machines to be

made

without

retooling,

re-

flects in

the

selling

price.

Elec.trical and Mechanical Construction

The

Magnetophon

77 is a

full

stereo machine.

This

means

that

it is

not

only

equipped

for

the

playback

of

professionally

pre-recorded

four-track

stereo

tapes

but

also for

making

stereo

recordings.

It

contains,

therefore,

two

complete,

separate

record/playback

amplifiers.

If

the

Magnetophon

75 was so

popular

for

its

com-

height

guides to be

made.

In this

connection,

special

pact

design

and

resulting

handiness,

how

much

more

mention

must

be

made

of the

rotating

tape

guide

will

this

popularity

apply

to the

Magnetophon

77.

roller

(Ill.

1),

unobtrusively

introduced

by

TELE-

There are,

however,

in this machine,

twice

as

many

FUNKEN

some

time

ago in the

Magnetophon

75,

electrical

components

due

to

the

presence of

two

which in the

meantime

has

proved

itself

so

well

in

the

complete

amplifier

circuits.

Magnetophon

76

and

77.

Indeed,

this

device

(Ger-

man

Federal

Republic

Patent

No.

848,271

dated

For

reasons of

both

space

and

heating,

the

tran-

28/7/1950), is one of the

little

secrets which

contri-

sistorization

of the

input

stage,

already

started

with

bute

to the

crystal

clear

tone

quality

of the

TELE-

the

Magnetophon

76, has been

taken a step

further.

FUNKEN

Magnetophon

tape

recorders.

The

problem

As a result, each channel comprises

two

transistors,

of

obtaining

a free

running

tape

is

not

One which is

a

twin

triode

and

the

output

tube

and

appears

as

sol

ved

by

simply

ensuring

that

tape

height

is

follows:

OC

603 -

OC

603 -

ECC

83 - EL 95.

controlled.

Rather

the

reverse

is

the

case as

the

In

order

not

to lose the

advantageous

signal-to-noise

tape,

which is

not a rigid

body

but

an elastic mass,

ratio

gained

by

the use of

hum-free,

low-noise

tran-

begins to

vibrate

longitudinally

due to the

rigidity

sistorized

twin

pre.

amp.

stages, in

that

section

of

of the

height

guides.

These

longitudinal

vibrations

the

amplifier

fitted

with

tubes,

both

ECC

83 tubes

are

audible

during

playback

as

wide

side

bands

to

are

heated

with

DC.

The

magnet

for

the

rubber

originally

clear

sounds.

This

phenomenon,

known

sheathed

pressure

rollers

is also

DC

operated

in

as

"rustle

effect",

is

especially

audible

with

pure

or

order

to

avoid

disturbing

hum fields in the

vicinity

almost

pure

sinusoidal

oscillations,

e. g.

whistled

of

the

recording

head.

recordings.

The

most

effective

countermeasure

to

Naturally,

the

recording

head

- as is

the

case

with

longitudinal

vibration

is to

steady

the

tape

by

all

TELEFUNKEN

tape

recorders

- is

surrounded

by

means

of a flywheel mass

located

as

near

as possible

a

double

shield

of rnurnetal,

while,

in the

record

or

to

the

head.

For

this reason it has

long

been

the

playback

position, a mumetal

flap swings

against

the

practice

with

studio

machines, to fit a

large

flywheel

head

from

the

front

thus

completing

the

shielding.

mass

between

the

recording

head

and

the

playback

head. A simple

experiment

will

show

that

the

small

With

the

Magnetophon

77, as

with

the

Magneto-

flywheel

mass

represented

by the

tape

guide

roller

phon

76,

special

value

is.

placed

on the free

running

in the

Magnetophon

75, 76

and

77, serves also to

of the

tape.

The

patented

TELEFUNKEN

automatic

eliminate

longitudinal

vibration.

With

the

tape

tape

tension

device

(German

Federal

Republic

running

at

1'/,

i.p.s.,

whistle

into

the

microphone

Patent

No.

840,014

dated

22/9/1950),

not

only

and,

during

playback,

hold

the

tape

guide

roller

ensures

that

tape

tension

during

rewind

is

constant-

back

with a match.

The

"rustle

effect"

will

be

ly

kept

below

300

gramms,

but

also,

independent

of

clearly

heard.

the

tape

diameter

of

the

LH

reel,

ensures

even

tension

along

the

entire

length

of

the

tape

which in

Operation and Switch Possibilities

turn

effects

constantly

even

tape

pressure

against

the

head.

The

head

assembly

with

its

three

height

Here

too the

thoughtfulness

of the

development

guides, is

pre-assembled

as one

unit

as this system

engineer

can be

clearly

seen.

The

convenient

push-

enables

even

more

exact

adjustment

of

head

and

button

control

system,

taken

over

practically

un-

J5!.g--rphon~_--J

.JJ u,

earphone

IIIustration 2:
Controls of

Magnetaphan

77.

v Remote control

Rodiow

A Full reel

B Counter C Tope

speed

D Empty reel

Stop

button S

button T

F,\ Ploybock track
F,

J selector butto

Start

Record trock

selector buttons

E Splicing rail

Micro Rodio

G

switch
ON/OFF,

H

modulotion
control

Modulotion

indicator

Q, Q,

p

o N M

L

K, K,

Extension

speaker

Record releose ON/OFF switch for Bockword or

Quick stop

Microphone

connections,

button built-in

speoker

forword rewind

button

inputs

2x2.5W

control