Australian monitor KLA User Manual

Australian Monitor

Introduction

Ktu

K snnlns LooP AMPLIFIERS

Australian Monitor is

the successful K-Series range, these amplifiers utilise

provide

system

detail

Hosting most of the features and loop amplifiers offer some additional

up of an lnduction loop system.

These

to

whilst maintaining

include:

,

Additional

construction

strapping

features include:

for

connectors, massive

proud

a constant

lntemal

10dB into compression indicator

lnput Level

level

Dual Low frequency output current limiting Loop disable relay at turn on Loop open / voltage too high indication

Binding Post and

Active

Signal Ground

ease

introduce

to

cunent into a single turn

total stability.

protection

limiter

Balanced lnputs

of

with 250mV threshold and

Control

output cunent indicators

Speakon

"LlFT"

Custom

servicing, well

heatsinking, Front to back cooling and a dual speed axial

you

to

circuitry, controls

for adjusting input signal for the ideal operating window

switch.

its range of lnduction Loop amplifiers. Modelled

networks of the K-series Audio Amplifiers the KLa

loop connections

designed

regulating high current

our unique impedance and

lnduction Loop, resulting in clarity and

and lndicators

panel

front

(and

indication)

-

heavy duty chassis, open modular

assist

to

indication

power

supply, lnput signal

phase

in the conect set-

sensing

fan.

on

Protection

over-voltage

Breaker, The layout, stability, reliability and longevity.

features include:

protection,

lndependent

grounding,

DC supply rail Fuses.

decoupling and componentry have been optimised to

RF interference suppression, Short-circuit

ltu

Mainrs inrush cunent

suppression, lnput muting at tum on, lnput

protection,

provide

Mains

the user with

Circuit

Austdlan Monitor

KLa Loop Amplifiers 2

Front Panel

Your KLa loop amplifier is furnished with simple controls and indicators to assist in the set up of

the amplifier for driving a

to show the

1 Input Level

"lnput

A

suitable for

lnput Level lnput Signals between

proper

Level" attenuation control is

Controls and Indicators

operating levels

Control.

processing

Control

provides

properly

by the internal limiter.

-10

calculated lnduction Loop. The indicators

of input signals

provided

attenuation only.

and

+10d8

but OdB

provide

and output current.

as to adjust

so

The circuit is based on a fixed

The input of the unit can deal with Gain

(.775v)

preferable.

is

your

incoming signal

visual detail

gain

and thus the

to a level

Levelled

2 Operating Window

This Bi-Colour LED indicates signal level to the unit's limiter circuitry.

Green indicates the

applied signal should be illuminating

position.

Red indicates that the signal is 10dB or more

illuminated continuous

3 Output

This LED is

driven into clipping. ldeally this LED

too high, that the loop has

4

Output

"Output

The

peak

the

all the time but should flash with toggle between the LED illuminating

Voltage

provided

Drive Control.

Drive" level control dictates current drive

current level required to

Indicator.

threshold

Indicator.

Clip

and will illuminate amber when the output voltage

gone

of the

open circuit

limiter and is factory

this

with the lnput Level control in the appropriate

LED

into compression. This led should not be

programme

green

should never illuminate and implies that

and/or the loop impedance is too

properly

drive the

peaks.

and red.

to the loop. lts

loop as indicated by the chart on

preset

for 250mV

ldeal signal level will cause a

(-10dB).

of the amplifier is

the output level is

high.

position

will be dictated by

page

Any

8.

/tu

Australlan Monitor

5

Current Level

"Cunent

The

Indicator.

Level"

LED

provided

is

as indication

to show the

peak

KLa Loop Amplifier.s

cunent

in the loop.

3

KLa I - KLa2 -

see chart for

6 Fault

Green

3Amps,

=

5 Amps,

=

loop calculations.

/ Current Limit

This amber coloured

indicates

infrequent illuminating

The

on the output.

7

On lThermal Indicator

This is on and receiving

ln the advent

temperature shut down and

has had a cool

suppression,

limiting of

flashing

of this

LED will also illuminate

a Bi-Colour

of a Thermal

of

of this LED

LED requires

LED which

mains

the amplifier isolated itself

down

input muting

Red

=6Amps.

Red

10 Amps

=

Indicator.

LED will

the cunent

power.

period

illuminate when

into the load

peaks

on

the output drive

with other

will normally illuminate

Overload this LED will tum

has exceeded

from the loop.

faults such

the unit

and the

loop relay isolation

load cunent exceeds

and will flash

at lower

a safe level

The fan will

frequencies

to be reduced.

as blown negative

green

red indicating

of operation

continue to

with

quite

is

and indicates

will restart automatically

will be bypassed.

a safe value.

programme peaks.

acceptable.

rail fuse and short

that the amplifier

that the intemal and that the amplifier

run and once the

providing

inrush

The led

Constant

circuits

operating

amplifier

current

The

is

has

8 Power

Press the switch down

should

ofr.

At tum-on

Switch

be the last

a number of events

a)

Mains inrush cunent

b) A relay isolates

c) lnput signal to

for

ON and up for

piece

of equipment

happen during

suppression is

the lnduction

the main amplifier

Loop until the amplifier

OFF.

you

tum on and

the

provided,

is muted

Like

any other

power-up

(>30d8)

power

the first

of

has established

for approx'2

piece

the amplifier.

amplifier in

of equipment

itself,

to 3 seconds.

any system it

you

tum

/tu

Aushalian

lYonitor

Rear Panel

KLa Loop Amplifters 4

,//Ll< r-;a*

l"^ffi.*.74rz

I\lll sm.G.xmd

I Balanced Input & Strapping

A female 3-pin XLR connector is

provided

strapping/looping

Pin allocation is: Pin-l

2

Signal Ground

When this switch is engaged it disconnects signal

be used when

as a strapping connector wired in

"HUM"

The

between

Lift

amplifier

multiple amplifiers.

Signal Ground,

=

Switch

is caused by earth loops or stray magnetic fields.

should

\

ro7'e!.o/.oh,/

Connection

provided

Pin-2

be tumed

Loop Outputs.

Your Kla Loop Amplifier is cunent Binding Post outputs are

The Speakon connector is wired 1+

provided

with 2 options for output termination of the loop. Heavy

as well as a Neutrik

positive

=

Mains Lead

as input connection. A male XLR connector is

=

parallel

(reverse phase),

Cold

ground

with the input XLR allowing

phase).

(in

=

Hot

Pin-3

from the amplifier. lt is intended to

off before engaging this switch.

& 1-

negative.

=

"Speakon"

connector.

Your amplifier is supplied with a heavy duty mains lead

mains supply voltage marked on the rear

coloured in accordance

are

Brown

Mains

A

amplifiers

current internal fault or in continued overload conditions,

"push

Circuit

to reset" thermal circuit breaker is

power

Breaker

supply.

the

with

Active, Blue

=

Your

will isolate the

lt

following

unit

panel

Neutral, Green/yellow = Earth.

=

must always be earthed!

"active"

your

of

code.

supplied to

mains conductor in the event of a

D.C. Rail Fuses

"fast

3AG

rails for

stage.

The

bloy/' type fuses are

your

fuses must be replaced with the same type fuse.

amplifiers output stage. These fuses

provided

KLal

and are in series with the

Amps, l(La2

=

8

='10

(power

amplifier. The wires in the mains lead

provide

cord) appropriately rated for the

provide

Amps.

overall

positive

overall

protection

and negative supply

protection

of the output

of

your

high

/tu

Aushalian

Monitor

KLa Lpop Amplifiers 5

To

set up

Once all connections have

I Make sure all the

2 npply signal

Turn up'INPUT

3

and red illuminations.

your

(applied

KLa Loop

been made:

controls are down before

signal should be

LEVEL'knob until

Amplifier:

you

tum

gain

levelled

'OPERATING

the amplifier ON.

and be around odB

WINDOW"

LED is flashing between

NOTE: The red LED should not be on constantly, but should flash with

4 Tum up

KLa 1

KLa2

NOTE: These

5 Use

'OUTPUT

Green Green

a field strength meter or loop listening device to monitor level and coverage in the loop.

DRIVE" control to the desired cunent level.

3Amps,

=

5 Amps,

=

LEDS are to illuminate on

Red = 6 Amps. Red

10 Amps.

=

peaks

only.

-

0.775 volts

programme peaks.

)

green

-

The do's and don'ts

There are a few As there is a strong field radiating from the cable it can interfere with other

your

thus

loop

precautions you

should be restricted

need to consider when

(as

far as

possible)

installing

to a defined

your

lnduction Loop System.

listening area.

Do:

Always ensure the installation of

As far as

above or below this is acceptable but

Run balanced signals / cables wherever

possible

have

your

loop at the same elevation as

is in accordance

Loop

cunent drive

more

possible.

may

with wiring regulations.

the listening

be

required.

position,

Do Not:

Do not install the loop with other cable runs - never run the loop cable in

and always cross other cables at right angles.

Do not run

performance.

your

Loop cable

conduit

in

or in / or near shielded trays as this may effect its

parallel

electronic equipment

1 to 2 metres

with other cables

'

Do not have dynamic type microphones, which may be a the loop. the system.

I

The coil

may

pick

up the radiated field from the

part

of the signal source, inside or

loop and cause feedback to occur

near

Do not run unbalanced signals / cables as they may be affected by the Loop and cause

feedback.

/tu

Ausbdan Monitor

in

KLa Loop

Amplifiers 6

Why An Induction

Usually,

The system is driven by an amplifier

encompassing radiated field induces cunent of the hearing impaired.

Because a length of wire is used as the load from which the signal is radiated, it makes special demands The wire will exhibit a very low impedance at low frequencies and exhibit a higher impedance as

the frequency rises. To maintain

bandwidth) are a constant voltage type and will not drive an lnduction Loop output is constant will reduce as the frequency

The

an lnduction

on

the amplifier driving it.

you

graphs

below show

Loop system is installed as an aid to

the listening area. A field is radiated from the cunent

must maintain a constant cunent into the load. Normally encountered amplifiers

(regardless

Loop system.

provide

which can

to flow

of

rises.

the transfer characteristic of a Klal

(more

constant radiation from the

a

load variations) and fidelity will be lost in the system as radiation

often than not) in a

provide

a constant cunent into a wire loop

audio for

"T-Coil"

piece

System

into 50

iii

hearing impaired.

the

flowing in the loop, and this

in the hearing aid device

of wire

metres of 2.00 mm2

(through

properly

the audio

as their voltage

cable.

'-i

0t(

OutDut Voltase Vs Freouencv

graph

The above

voltage variation of e KLal required to maintein e

constant current of 5 amDs into the lnduction

This Loop exhibits an impedance of 0.5 ohm at 200H2 and

Power into type amplifier diving the same loop at 5 amps

Also the amplifier is driving a virtual short circuit for the lower frequency spectrum

invoke

the

protection

(lowest

loop

circuitry to continuously operate in

Two traces are shown which

show a fully- compensated high frequency response. This adjustment would normally factory

not

allows for

pres'et (no

properly

the

compensation), but could become useful in circumstances where the

calculated.

__ll

trace) shows the output

2O0Hz

@

above.

higher frequency

12.5 VA but

=

The KLa Loop Amplifiers

t* l0

LooD.

@

response

lo t(

Current OutDut Vs Freouencv

graph

The above

Frequency Response relative to cunent output of the

KLal. odB reference

an

impedance

10kHz the 200H2 would be down 1$dB

constant voltage type amplifiers.

power

(lowest

trace) shows the

5amps @ 200H2.

=

of 4 ohms at lokHz.

1O0 VA. A constant voltage

=

10kHz.

@

and thus would

have an internal adjustment

to be extended. The upper trace on the

\ \i

vn

.,*

*r0

(RV-1)

graphs

be left at

loop

i

\i

\

' '"']

the

was

The hearing impaired can detect more detail in the this reason lnduction Loop

have a built in limiter to further reduce transients in the applied

Systems

should be fed with

programme

gain

/tu

if dynamic range

levelled signal. The KLa

programme

source.

is reduced. For

Ausbalian Monitor

amplifiers

KLa Loop Amplifiers 7

Calculating

The following

installation. You

reguired and

information is

to select the appropriate

H|GH cuRRENr TERMTNA-floN

OUTPUT TFRMINAI S :

will need to know the size of

Induction

the

')c-

provided

Loop.

as a

gauge

LOOP

",o""

guide

for the

your

of

the wire for the loop.

I

-

proper

loop to ascertain the

calculation of

your

lnductive Loop

peak

drive cunent

LENGT

H

I

FEED

LOOP

PARALLELING

IIF REOUIRED}

First we need to calculate the Peak cunent required in the loop. The lnduction Loop Peak

Chart

cunent

(page

8) shows the relative cunent required for different size loops

(Ampere)

curve. lf

your

LINKS

.-

loop is a circle, simply approximate it to a square.

BREADIH

-.....*

-

Pick the closest

Cunent

Then we need to determine the length of cable required

perimeter

the

Now we need to calculate the

of the loop.

To this add the loop feed distance, for a total wire length.

gauge

of the wire. lt is recommended that the

(length

of the loop is between 0.5ohm and 1.0 ohm. We also recommend that

rating of the cable is well above the insulation is of a heavy duty type with a

To help reduce the variation in wire heavy duty figure-8 cable with a termination block

allow

you

parallel

to

the conductors

Stranded

1.00

1.50

2.OO

2.50

-3.00

32tO.20

30/0.25

40t.o25

50/.025

63tO.25

peak

cunent required into the

good

dielectric strength and

gauges

if the resistance of the loop is too high.

needed to satisfy every loop we suggest running a

(as

shown in the above diagram) which will

copper conductors to 836360

17 16 14 13 12

For example: A loop that is 15 metres by 40 metres requires a

perimeter To achieve a D.C. resistance of between 0.5 and 1.0 ohms we would need to use 12 AWG wire which will

required

amps.

110 metres and the loop feed is 10 metres long, thus 120 metres of cable is required.

= give

us 0.72 ohms total D.C. resistance and a cunent rating 2.5 times the

(20

amps).

Paralleling 16 AWG wire would

give

us a similar result

+

breadth)

x 2.

this

total D.C.

you

ensure

(>2

loop

high thermal capacity.

-

1991

1.85

1.26

0.98

0.76

0.60

peak

times) and

cunent of 8 amps. lts

0.756 ohms for 18

@

give

will

resistance

cunent

the

that

6

I

11

15

20

peak

cunent

us

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