Harman Kardon A400 Owners Manual - Page 2

OUTPUT

Two

receptacles,

marked

"Output"

will

be

found

at

the

rear

of

the

chassis.

For

your

convenience

in

connecting

to

the

amplifier,

a

36"

shielded

cable

will

be

found

in

the

Counterpoint

package.

Plug

one

end

of

this

cable

into

either

one

of

the

two

out-

put

receptacles,

and

the

other

end

into

the

appropriate

amplifier

input

receptacle.

Since

the

output

circuit

of

the

Counterpoint

in-

cludes

a

cathode

-follower,

this

cable

may

be

extend-

ed

to

any

reasonable

length

without

deterioration

of

tone

quality.

The

second

output

receptacle

may

be

similarly

connected

to

a

tape

recorder,

to

provide

program

mat-

erial

unaffected

by

the

tone

and

volume

controls

of

the

amplifier.

The

output

level

of

the

Counterpoint

may

be

adjusted

to

suit

the

input

requirements

of

the

ampli-

fier,

or

to

balance

with

the

volume

of

another

program

source

(such

as

a

record

player),

by

means

of

the

control

marked

"Output

Level".

VENTILATION:

All

electrical

equipment

generates

heat,

which

must

be

allowed

to

escape.

Although

the

Counterpoint

is

well

ventilated

in

itself,

sufficient

space

should

be

allowed

around

it

to

permit

free

air

flow.

If

it

is

placed

in

a

bookcase,

it

should

be

located

well

toward

the

front,

to

provide

as

much

clearance

as

possible

at

the

rear.

Do

not

put

books

or

other

objects

on

top

of

the

Counterpoint.

Covering

the

perforated

tube

grill

will

reduce

the

ventilation

and

result

in

sharply

reduced

component

and

tube

life.

OPERATION:

CONTROLS

The

Harman-Kardon

Counterpoint

has

only

2

front

panel

operating

controls.

The

Tuning

Knob

(at

the

right)

is

used

to

tune

to

the

desired

station.

The

Power

-AFC

control

(at

the

left)

serves

to

turn

the

power

off

in

its

extreme

counter

-clockwise

position.

A

small

amount

of

rotation

from

this

position

will

turn

the

power

on,

with

a

click,

and

further

rotation

serves

to

adjust

the

degree

of

Automatic

Frequency

Control

up

to

a

maximum

at

the

extreme

clockwise

position.

TUNING

METER

The

precise

HARMAN-KARDON

tuning

meter

oper-

ates

whether

AFC

is

in

circuit

or

not.

When

the

Counterpoint

is

tuned

completely

off

any

station,

the

tuning

meter

will

point

to

zero.

As

you

tune

through

a

station,

the

needle

will

swing

to

one

side,

then

to

zero,

then

to

the

other

side,

and

as

you

tune

away

from

the

station,

back

to

zero.

The

tuning

is

proper

only

when

the

needle

points

to

approximately

zero.

AUTOMATIC

FREQUENCY

CONTROL

(AFC)

FM

Broadcasting,

by

its

very

nature,

eliminates

almost

all

natural

and

man-made

static.

However,

the

characteristics

of

FM

which

make

this

possible

also

make

for

problems

in

tuning.

The

HARMAN-

KARDON

Counterpoint

incorporates

an

effective

Automatic

Frequency

Control

(AFC)

circuit

that

over

these

problems

and

insures

proper

tuning

even

if

the

manual

tuning

is

not

accurately

done.

The

fol-

lowing

experiment

will

lead

to

an

understanding

of

AFC,

and

the

fuller

enjoyment

of

the

Counterpoint.

First,

rotate

the

"Power-AFC"control

to

the

extreme

clockwise

position.

Now

tune

across

the

scale.

Note

how

the

stations

"pop"

into

place,

one

after

the

other.

Now

tune

to

any

station,

preferably

one

with

a

musical

program.

Turn

the

"Power

-AFC"

control

counterclockwise

as

far

as

possible

without

turning

the

set

off.

This

defeats

the

AFC.

Tune

slowly

through

the

station

from

left

to

right.

Notice

that

there

are

three

points

where

the

station

sounds

clean,

interspersed

with

points

of

distorted

sound.

The

middle

clean

-sounding

point

is

the

proper

tuning

position

for

the

best

tone

quality

with

minimum

noise

and

interference.

At

this

point

the

tuning

meter

will

indicate

proper

tuning.

Tune

slightly

away

from

the

proper

tuning

position,

until

the

sound

is

distorted.

Note

that

the

tuning

meter

will

indicate

improper

tuning.

Now

reactivate

the

AFC

by

turning

the

"Power

-AFC"

knob

to

the

right.

You

will

notice

that

the

sound

cleans

up

and

the

proper

tuning

in-

dication

is

restored,

as

if

the

receiver

had

been

man-

ually

retuned.

Actually,

the

tuning

has

been

electrically

read-

justed

by

the

operation

of

the

AFC

circuit,

which

automatically

retunes

the

electronic

circuits

to

the

center

of

the

station

channel.

The

AFC

circuit

of

the

Harman-Kardon

Counter-

point

performs

the

further

function

of

overcoming

any

tendency

of

the

tuner

to

drift.

In

order

to

take

maximum

advantage

of

the

benefits

of

AFC,

it

is

suggested

that

tuning

be

done

with

AFC

off,

to

render

the

indication

of

the

tuning

meter

more

precise.

When

AFC

is

then

turned

on,

the

tuning

will

be

improved

by

a

ratio

of

10

to

1.

This

procedure

is

especially

recommended

in

those

areas

where

a

weak

station

is

found

close

to

a

strong

station.

Under

this

condition,

the

AFC

may

tend

to

reach

for

the

strong

station

and

completely

skip

over

the

weak

one.

If

the

weak

station

is

tuned

in

without

AFC,

it

will

be

locked

in

when

the

AFC

is

turned

on.

Another

procedure

might

be

to

find

that

setting

of

the

AFC

control

which

provides

the

exact

amount

of

AFC

action

for

most

convenient

tuning

in

your

location.

To

do

this,

tune

to

a

portion

of

the

dial

where

a

strong

station

is

found

immediately

adjacent

to

a

weak

station.

(If

this

situation

cannot

be

found

in

your

location,

leave

the

AFC

control

at

maximum).

Harman Kardon A400 Owners Manual - Page 2

Output, Ventilation, Operation, Controls

Page 2 highlights