TELETRONIX LA-2A - CONTROL SETTINGS; VU METER; STEREO OPERATION

TELETRONIX LA-2A

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away

from

the

straight

"No-Gain

Reduction"

line

is

determined

by

the

setting

of

the

"Peak

Reduction"

control.

It

can

be

seen

from

the

curve

that

compression

Occurs

and

gradually

in-

creases

over

the

first

10 DB of

input

level

rise.

The

slope

of

the

curve

then

becomes

horizontal,

preventing

an

increase

of

output

level

regardless

of

input

increase.

CONTROL SETTINGS

It

is

recommended

that

the

"Peak

Reduction"

control

be

set

to

prevent

increase

in

output

level

beyond

the

100%

modulation

point.

This

setting

should

be

made

on

typical

program

material.

Setting

of

the

"Gain"

and

"Peak

Reduction"

controls

are

independent.

However,

the

"Gain"

control

should

be

set

to

provide

sufficient

output

after

the

"Peak

Reduction"

control

has

been

adj

usted.

The

"Peak

Reduction

"

control

should

be

set

for

the

desired

amount

of

gain

reduction

as

indicated

by

the

meter

.

Continuous

extreme

reduction,

such

as

20

or

30 DB,

does

tend

to

reduce

the

dynamic

range

of

music.

Maximum

benefit

is

obtained

by

running

4 to 8 DB of

compression

continuously.

This

will

usually

cause

full

limiting

to

occur

when

100

%

modulation

is

approached.

For

ease

of

control

and

to

prevent

overload

of

the

input

transformer,

sufficient

fixed

pad

should

be

placed

ahead

of

the

LA-2A

to

allow

normal

output

at

approximately

50%

setting

of

the

gain

control.

VU

METER

The

VU

Meter

serves

two

functions;

it

indicates

output

level

as

well

as

gain

reduction

directly

in DB.

When

the

meter

selector

switch

is

placed

in

the

"output"

position,

the

meter

will

indicate

output

level

across

the

600 ohm

terminals.

The

meter

is

calibrated

to

read

0

VU

or

100

%

when the

amplifier

output

is

+10 DBM

or

+4

DBM,

depending

upon

the

switch

position.

The

position

marked

"Gain

Reduction"

permits

the

meter

to

indicate

the

amount

of

gain

reduction

or

peak

limiting

directly

in DB.

During

periods

of no gain

reduction

the

pointer

will

return

to 0

VU

on

the

meter

scale.

The

pointer

is

initially

set

to

this

position

by

means

of the

screw

driver

adj

usted

control

located

on

the

left

end

of

the

front

panel.

STEREO

If

two

LA-2A

Leveling

Amplifiers

are

to be

used

in

tandem

for

stereo,

the

gain

reduction

of

each

amplifier

can

be

made

equal,

regardless

of

which

channel

is

instigating

the

limiting.

This

is

accomplished

by

interconnecting

terminals

6

and

7 of

the

LA-2A

Leveling

Amplifiers.

The

interconnecting

wire

should

not

be

over

two

feet

in

length

and

should

be

shielded,

the

ends

of

the

shield

being

connected

to the #7

terminals

(ground).

Stereo

"set-up"

is

as

follows:

1.

Connect

the

input

terminals

of

the

left

and

right

channel

LA-2A

to an

audio

oscillator.

Make

certain

that

the

amplifiers

are

connected

in

phase

to

the

generator.

LA-2A

(3-66)

Page

5

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Other manuals for TELETRONIX LA-2A

Operating Instructions14 pages