Paso LAX50 User manual

1
Loop amplifier LAX50
Instructions for use
FEATURES
 Up to 50m2coverage
 2 Inputs
 Phantom Power
 Current Mode Output
 Integrated PSU
 Soft Start
 Compressor
 Noise Meter
 True Operation Indicator
 Protected Mix Control
 Protected Output Drive Control
 Power Indication
 3A Peak Current Capability
DESCRIPTION
The LAX50 is part of PASO range of audio frequency induction loop (AFILS) amplifiers.
The unit is designed for user-friendly installation to walls, vanity panels, desks and counters. The unit is compact, the front is printed with the
AFILS logo as well as text boxes to allow the name of the responsible person and their contact number to be written in. The controls (Mix and
Drive) are recessed to hinder unauthorised adjustment, and LED indication is provided for the presence of power and loop current.
The amplifier has two inputs to accept microphones and other signals adapted to such level. The inputs are mixed together and the balance
between the two inputs is set with the mix control, this allows the unit to operate with a main microphone and an ambience microphone if
required, or in a TV lounge to allow a scart connection to the television to be balanced with an ambience microphone for conversation. The unit
incorporates the latest design in audio processing allowing varying microphone levels to be compensated for automatically while preventing any
sudden loud noises from reaching the output stage. The compressor design automatically adjusts the release time providing high quality music
with a slow release and speech with a relatively fast release. The compressor ratio is dynamically variable and will automatically change from
1:1 to over 20:1 in the case of limiting. The unit also provides an automatic noise suppression system, reducing the level of audible hiss from
the compressor as gain is added to the system. The output stage for the LAX50 incorporates a true constant current design, which will drive loop
coils from 0.1Ωto 1Ωand is specifically designed for single turn loops in rooms. The output level is set using the drive control and is protected
against over temperature and DC offset and has a soft start facility removing loud clicks and pops when the unit is turned on.
INSTALLATION
The LAX50 is designed to provide loop coverage for counters, desks and interview rooms, as well as larger areas up to 50 m2(see note 1). To aid
installation, a range of accessories are available including pre-made telecoils, loop cable, discrete clip microphones and scart adapters. Installation is
simplicity itself, the unit should be sited in a convenient place (ideally as close to the area to be covered as possible) the loop cable (a single turn loop of
between 0.5 mm and 1.5 mm CSA cable) or telecoil is installed securely (see note 2) and the microphone(s) are located as close to the area(s) where the
sound is to be picked up from (see note 3). Mains power can now be applied using the cable supplied, the output drive control and microphone
mix controls can now be adjusted to the users preference. This is best done with a loop field strength meter during installation, or a loop
listening device (good practice is to supply a loop listening device to all installations to allow the responsible person to test the loop
periodically and record correct operation in a log booklet). The loop can consist of either cable, or a pre-made telecoil. The latter is ideal for
quick installation to bank counters and ticket offices and should be placed as close to the customer as possible. The telecoil produces a field
about 1.2m in diameter allowing them to be placed on alternate serving positions in densely populated bank halls. If the area to be covered
is larger than that covered by the telecoil, then a single turn wire loop should be employed.
APPLICATIONS
The following are a few examples of the
uses for the LAX50 AFILS amplifier,
including the likely accessories required.
Counters
Using the telecoil, with either the clip
or desk microphone
Interview Room
Using the telecoil on the desk, with
the desk microphone
Meeting Rooms
Using a loop cable and either desk or
clip microphone(s)
TV Lounges
Using a loop cable and Scart lead, with
optional microphone
Sheltered Housing
Using loop cable, clip microphone and
doorbell interface
POWER SUPPLY
This equipment is designed for use with a mains voltage of 230 V ± 10% 50/60 Hz. The LAX50 is supplied with its own power-supply cable, which is
equipped with an earthing wire. The earth terminal of the mains plug should never be removed under any circumstances. Connect the mains plug of
the LAX50 to the power mains using the cable included in the supply. Make sure that the power outlet is equipped with a connection to earth in
accordance with the law.
The replacement of fuses must be carried out by specialized personnel only: when the cover is removed, parts liable to cause electric shocks are
exposed. Before removing the cover, always make sure that the power cord has been disconnected. In the event that liquid is accidentally spilt
onto the equipment, disconnect the mains plug immediately and contact the nearest PASO Service Centre.
SAFETY NOTES

2
LAX50
The loop consists of insulated cable between 0.5 mm and 1.5 mm CSA
(we recommend tri-rated switch gear wire, this has a much thicker jacket
and is easier to clip down as well as being harder wearing). The cable
should be securely clipped at either skirting level (taking adequate care
for protection when going past doorways) or at ceiling level (2.4m). Once
the loop cable is installed the ends should be bared and placed into the
orange loop connector on the top of the amplifier. The cable grip is
opened using a small flat blade driver. Conventionally the loop start is
connected to + and the end to .
MICROPHONES
Microphones should be placed near to the source of the sound for the
loop. No one microphone will fit all uses, PASO provide a variety of
microphones; in general the tie clip microphone will give good coverage
placed on the mullion of a counter or on the side of a television or monitor.
The desk microphone is particularly suited to desks, board room tables
and counters. Microphone cables must be run separately from the loop
cable, under no circumstances should the cables be tied together for any
distance, this will cause magnetic feedback and the unit will not perform
correctly. The microphones simply plug into the 3.5mm jack sockets on
the top of the amplifier.
TECHNICAL SPECIFICATIONS
Audio inputs 2 off
Type Microphone 3,5 mm mono jack
Phantom 4,5 V 1 mA
Sensitivity -50 dB
Mains input
Voltage 230 V ± 10% 50/60 Hz
Power 20 VA Max
Internal fuse F100 mA
Indications & Controls
Led indicators 2 off, power and loop current
User Controls Mix and Current Drive
Protection Recessed screwdriver adjust only
Audio Processing
Compressor Variable Ratio 1:1 to 20:1
Attack 10 ms
Release Automatic from 500 ms to 1500 ms
Noise reduction Yes, limits bandwidth to 8 kHz @ full
gain, 16 kHz @ -6 dB
Dynamic Range > 60 dB
THD < 0.5%
Output Stage
Type Current Mode
Loop impedance 0.1 Ωto 1 Ω
Peak Current 3.5 A Peak
125 ms Burst 3 A Peak
RMS Current 1.5 A (@ 1 kHz)
Protection Offset DC, Thermal, Short-circuit,
Soft Start
Dimensions
Extents 170 x 91 x 33 mm
User Controls Mix and Current Drive
Protection Recessed screwdriver adjust only
Via Mecenate, 90 - 20138 MILANO - ITALIA
TEL. [phone] (15 linee r.a.)
FAX [phone]
http://www.paso.it
UDT- 12/02 - 11/576 - FC
S.p.A
 NOTE 
While thanking you for having chosen a PASO product, we would like
to remind you that our company works according to a certified Quality
System. This means that all our products are checked during every
phase of manufacturing in order to ensure that you will be fully satisfied
with your purchase. In any case, the guarantee will cover any
manufacturing flaws during the guarantee period. We recommend
that you read these instructions for use and follow them carefully in
order to exploit in full the performance of this product and use it
correctly.
PASO will not accept any liability for damage to property and/or
persons arising out of incorrect use of the equipment or of procedures
that do not comply with the instructions provided in this booklet.
PASO S.p.A. strive to improve their products continuously, and
therefore reserve the right to make changes to the drawings and
technical specifications at any time and without notice.
Notes
1. Loop coverage: the unit is rated at 30 m2coverage for a square room
(5.2 m a side) where the loop cable is fitted at ceiling (2.4 m) or
skirting board level. If the room is rectangular the unit will cover 50 m2
(10 m by 5 m) with the cable at ceiling or floor level. If the floor
contains a lot of steel (computer decking) or aluminium or the cable is
placed at a higher level than 2.4 m then the coverage will be reduced
(approximately 20% per additional metre in height).
2. If there is any doubt as to the construction of the building, it is always
best to lay a temporary loop in the approximate position the final loop
will occupy, this will determine the operation of the loop. Many new
buildings contain aluminium in lost screed flooring, loops placed on the
floor near this aluminium will fail to operate satisfactorily.
3. Microphone cables must be run separately from the loop cable,
under no circumstances should the cables be tied together for any
distance, this will cause magnetic feedback and the unit will not
perform correctly. Good practice is to twist the loop feeder cable
together between the start and end of the loop and the amplifier.
PASO provide the telecoils with twisted feeder cables, and feeder
cable is available in 5 m and 10 m lengths.
COMMISSIONING
Before applying power to the unit ensure the drive control (middle of the
panel) is fully anti clockwise. Apply power, the green power LED should
illuminate. Next set the Mix control that balances the two MIC inputs
level. If only one is used then turn the control fully anti clockwise (input
1 used) or fully clockwise (input 2 used).
If both mics are in use set to the center position initially. Using a field
strength meter or loop listening device slowly turn the drive control
clockwise with someone speaking near the microphones positions
(alternatively a small radio or pink noise source giving 65 dBA output can
be used), the desired field strength is 0dB (100 mAM 1 ) at the center of
the room, or at head height in front of a counter using the telecoil.
As speech is being picked up the current LED should blink on the front of
the unit, if it does not blink, and field strength is not achieved, switch off
and check the wiring and loop continuity. Once the field strength has
been verified, the mix control can be adjusted to give the best balance if
multiple microphones are used. The check boxes on the front of the unit
can now be completed with the responsible persons name and contact
details (this should be the DDA officer for that section or the company
using the unit). It is good practice to provide a site with a loop listening
device so the responsible person can periodically test the installation and
log operation in a booklet. Your LAX50 should now be fully operational.
ACCESSORIES
 LAC50 Telecoil
 LAM50 Tie Clip Microphone
 LASC50 Scart Adapter