LT1 Instructions
Description.
This Home Loop System enables you to listen more easily, with no direct connection, to the TV or
other sound source. It is used in conjunction with a hearing aid with a switch position marked "T" or
"MT", this is found on most 'behind the ear' hearing aids. The system picks up the sound from the TV
via a microphone and feeds it to the amplifier. The amplifier passes the sound to a loop of wire around
the listening area, which in turn transmits the sound inductively to the hearing aid. You may adjust the
volume to your own level without affecting other people.
The loop system is supplied ready for use with a fitted mains plug, a miniature microphone, "Velcro"
pads, loop cable and a packet of cable clips.
Instructions for use.
1. Place the amplifier in a convenient position near to the television. Place the loop cable around the
room. Leave one end of the cable at the amplifier and lay the cable around the edge of the room.
Make a complete circuit back to the amplifier. The cable may be tucked under the edge of a carpet, or
fixed to the skirting board or picture rail. At doors either fix the cable around the door frame or tuck it
under the carpet.
2. Connect the cable to the back of the amplifier (see following diagram).
Connect one end of the cable to the left hand pair of terminals. When the terminal is pushed a hole will
appear, push the wire into the hole, making sure that only the wire and not the plastic insulation goes
in, then release the terminal. Ensure the wire marked black goes to the black terminal and the wire
marked red goes to the red terminal. Similarly, connect the other end of the cable to the right hand pair
of terminals, black to black and red to red. If excess cable is coiled up it may affect the frequency
response of the system. Excess loop cable can be cut off as long as a MINIMUM length of 35 feet (11
metres) is left connected to the amplifier. Longer cables are available, if required, up to a maximum of
120 feet (37 metres).
3. Plug the microphone lead into the Microphone socket marked "A" on the front panel. Place the
microphone on the television speaker grille, using one of the "Velcro" pads supplied. Peel off the
backing paper and press the pad firmly into place. The "Velcro" already on the microphone will then
fasten to it if pressed lightly into place. To remove the microphone pull gently and it will come free
allowing its use on other equipment.
4. Plug the amplifier into the mains and switch on at the socket, then switch on the amplifier by
pressing the green rocker switch, which will glow. Make sure that the two round switches to the left of
the green on/off switch are in the off position. Set the television to the normal listening level for the
other members of your household, switch your hearing aid to the "T" or "MT" position. Adjust the
loop amplifier volume control for the best results in your normal viewing position.
5. Tone Control. The amplifier is fitted with a variable tone control to the right of the Volume
control. In the «_High»_ position the amplifier will emphasise the higher frequency range and in the
«_Low»_ position the lower frequency range will be emphasised. In the «_Normal»_ position the high
and low frequency ranges are NOT emphasised.
6. Automatic Gain Control AGC. The switch marked AGC operates the automatic gain control,
when this is switched on the output signal from the loop will remain almost constant despite variations
in the sound level picked up by the microphone. This feature can save adjusting the volume control for
different programmes.
7. Priority control PRI. If a second microphone is plugged into microphone socket marked B this
can be made to override the signal coming from the microphone in the A socket or the auxiliary input.
When the PRI switch is in the "on" position the volume of the A microphone will be turned down when
the B microphone picks up a sound above a threshold level. This can be useful if a second microphone
is used to monitor a doorbell or telephone bell, or another person wants to talk to someone whilst they
are using the loop. However if a second microphone is used in a noisy room or the TV is turned up
loudly this feature should be turned off. When the switch is in the "off" position there is no override of
Microphone "A" by Microphone "B".
SWITCH OFF THE AMPLIFIER WHEN NOT IN USE.
Further Information
An auxiliary input socket is provided on the rear of the amplifier. This enables television, radio, audio
and video equipment to be connected directly to the loop amplifier via headphone or auxiliary output
sockets. This can be particularly useful in very noisy rooms or when no sound at all is wanted from the
TV or a direct connection to a stereo TV or sound system is required. This socket is wired for signal in
on pins 3 & 5 and ground on pin 2. This socket is connected to the same input channel as microphone
A and can be overridden by microphone B if the priority feature is switched on. To make use of the
input socket the equipment to be connected must have a suitable OUTPUT socket. These may be
described in different ways and were originally intended for various purposes. They may be marked
Audio out, Tape out, or Headphones. The SCART or EUROSOCKET on modern TVs can be used but
an adaptor may be required if it is already being used for connection to other equipment. On some TVs
using the headphone socket turns off the TV speaker, on others there is a switch that allows the speaker
to be left on if required.
Fault Finding
If a loop system was working normally the last time it was used and then fails to work then suspect
damage to the loop cable, including connections, or microphone lead. When re-arranging furniture or
spring cleaning care needs to be taken not to damage these parts.
WARNING: THIS APPARATUS MUST BE EARTHED
IMPORTANT: The wires in the mains lead on this amplifier are coloured in accordance with the
following code GREEN/YELLOW=EARTH BLUE=NEUTRAL BROWN=LIVE.
If you need to change the plug already fitted to this appliance these colours may not correspond with
the markings identifying the terminals in your plug. If this is so proceed as follows: The wire which is
coloured GREEN/YELLOW must be connected to the terminal marked with the letter E, by the earth
symbol or coloured GREEN.
The wire which is coloured BLUE must be connected to the terminal marked with the letter N or
coloured BLACK. The wire which is coloured BROWN must be connected to the terminal which is
marked with the letter L or coloured RED. This apparatus must be protected by a 3amp fuse if a
13amp(BS1363) plug is used. There are no user adjustable or replaceable parts inside the amplifier and
at no time should the user take the equipment apart.
724-040 1094
Home Loop System
Model LT1
Sarabec Limited 15 High Force Road Middlesbrough Cleveland TS2 1RH
Telephone (01642) 247789 Fax (01642) 230827 Text (01642) 251310
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