Harman Kardon A250 Owners Manual - Page 12

The

Model

A-250

incorporates

the

following

front

panel

controls.

Viewing

the

instrument

from

left

to

right

you

will

note

a

TREBLE

control

(

on/off

switch

is

incorporated

in

this

control),

BASS

control,

LOUDNESS

control,

BALANCE

control,

MODE

switch

and

FUNCTION

switch.

On

the

upper

left

section

of

the

front

panel

you

will

note

two

SPEAKER

SELECTOR

switches

and

a

CON-

TOUR

switch.

On

the

right

section

of

the

front

panel

there

is

a

RUMBLE

FILTER

switch,

SCRATCH

FILTER

switch

and

an

EQUALIZATION

switch.

TECHNICAL

EXPLANATION

OF

THE

CONTROLS

Since

a

stereo

amplifier

is

actually

two

amplifiers

in

one,

the

number

of

operating

controls

would

normally

be

doubled.

This

would

make

operation

un-

necessarily

cumbersome.

For

convenience

the

duplicate

controls

are

mechanically

tied

together,

or

ganged,

to

be

operated

by

one

knob.

Bass

and

Treble:

The

BASS

and

TREBLE

controls

on

the

Model

A-250

provide

the

full

range

of

tonal

adjustment

necessary

for

high

fi

delity

listening.

These

controls

can

either

boost

or

cut

the

bass

and

treble

tones

of

the

stereo

system.

The

controls

should

be

set

in

accordance

with

your

listening

preference,

speaker

character-

istics

and

room

acoustics.

Loudness

Control:

This

control

adjusts

the

volume

level

of

any

program

material

fed

into

your

stereo

system.

Its

effect

can

be

modified

by

the

CONTOUR

switch.

Contour

Switch:

One

of

the

limitations

of

human

hearing

is

its

tendency

to

lose

sensitivity

to

the

very

low

pitched

sounds,

as

the

program

sound

level

is

reduced.

It

is

this

characteristic

(known

as

the

Fletcher

-Munson

effect)

which

causes

one

to

play

music

programs

at

high

listening

level

in

order

to

experience

the

full

rich

tone

available

from

fi

ne

modern

recordings.

The

Harman-Kardon

CONTOUR

switch

compensates

for

the

Fletcher

-Munson

effect

thus

eliminating

high

listening

levels

as

a

requisite

for

full

enjoyment

of

reproduced

music.

For

low

level

listening

throw

the

CONTOUR

switch

located

on

the

front

panel

to

either

number

I

or

number

2

position

depending

on

your

listening

preference.

You

will

note

how

the

low

frequencies

become

more

apparent

while

th

volume

level

remains

unchanged.

Balance

Control:

The

nature

of

stereo

reproduction

is

such

that

it

requires

two

identical

channels

to

attain

the

highest

degree

of

faithfulness

and

spatial

distribution.

Any

variation

in

the

efficiency

of

one

channel

as

compared

to

the

other

will

disturb

this

relationship.

Since

there

may

be

slight

differences

between

the

two

speakers,

tape

heads,

etc.,

the

A-250

includes

a

control

to

balance

one

channel

against

the

other.

Sufficient

range

is

covered

by

this

control

to

permit

rebalancing

of

the

overall

system

even

in

cases

where

major

unbalance

exists.

This

control

may

be

set

anywhere

within

its

range

to

attain

system

balance.

When

the

BALANCE

control

is

properly

set,

the

apparent

sound

source

will

lie

in

a

broad

area

between

the

two

speakers.

When

the

BALANCE

control

is

rotated

to

the

right

the

sound

will

move

to

the

right

and

when

the

control

is

rotated

to

the

left,

the

sound

will

move

to

the

left.

Mode

Switch:

The

MODE

switch

selects

between

stereo

operation,

where

a

stereo

program

source

is

available,

and

monaural

operation

utilizing

the

full

power

of

both

chan-

nels

and

both

speakers

when

the

program

source

is

monaural

only.

Harman Kardon A250 Owners Manual - Page 12

TECHNICAL, EXPLANATION, CONTROLS, Treble, Loudness, Control, Contour, Switch, Balance

Page 12 highlights