Ampetronic CLS1 System manual

CLS1 Installation Handbook
1
Handbook Contents
•Safety
•Introduction
•Block diagram
•Overview
•Connections
•Installation
•Troubleshooting
•Accessories
•Technical Specifications
•Warranty
•Declaration Of Conformity
Box Contents
1 x CLS1
1 x ‘Installation Handbook’
1 x Deaf logo
1 x P-clip, nut & washer
This symbol is used to alert the user to important
operating or maintenance instructions.
The Lightning bolt triangle is used to alert the user
to the risk of electric shock.
SAFETY
1. It is important to read these instructions, and to follow them.
2. Keep this instruction manual in an accessible place.
3. Clean only with a dry cloth. Cleaning fluids may affect the equipment.
4. Do not install this equipment near any heat sources such as radiators, heating vents
or other apparatus that produces heat.
5. WARNING – THIS APPARATUS MUST BE EARTHED / GROUNDED.
6. Only power cords with the correct power connector may be used to maintain safety.
Cables incorporating the UK 13A fused plug, Schuko with earthing contacts and UL
approved “grounding type” are acceptable. These must be plugged into power outlets
which provide a protective earth.
7. Refer all servicing to qualified personnel. Servicing is required when the apparatus
has been damaged in any way, such as a power supply cord or plug is damaged,
liquid has been spilled or objects have fallen into the apparatus, the apparatus has
been exposed to any rain or moisture, does not operate normally or has been
dropped.
8. WARNING – To reduce the risk of fire or electric shock, do not expose this
apparatus to rain or moisture. The apparatus shall not be exposed to dripping
or splashing and no objects filled with liquids, such as vases, shall be placed
on the apparatus.
TO PREVENT ELECTRIC SHOCK DO NOT REMOVE THE
COVER. THERE ARE NO USER SERVICEABLE PARTS
INSIDE. REFER SERVICING TO QUALIFIED PERSONNEL.
ATTENTION: RISQUE DE CHOCS ELECTRIQUE NE PAS OUVRIR

2
INTRODUCTION
The CLS1 Induction loop driver has been designed as a high quality
amplifier for use in community centres, board rooms, churches, interview
rooms, meeting rooms and classrooms. Depending on a number of factors
regarding the installation of the loop and the set-up of the amplifier the CLS1
can provide compliance with IEC60118-4 for areas >200m2.
The unit is designed for wall or panel installation (or optional insertion into a
1U rack space), with a hinged and detachable lid which is secured by two
PH2 screws. All connections are made via screw terminal blocks within the
amplifier case and cables are brought into the unit through 20mm ‘knock-out’
holes on the top, bottom or back face of the amplifier. All adjustments are
made within the amplifier case reducing the likelihood of tampering after
commissioning.
Ease of installation and use have been major factors in the design,
combined with optimized performance, and the freedom from R.F.I.
generation.
The CLS1 has three audio inputs. A 100V line / speaker line, a balanced
line, and one which can be configured as balanced line or balanced
microphone.

3
Block Diagram
Input 3 100V / speaker
100V /
speaker gain
Line gain
MIC / Line
gain
AGC LED
MIC / Line
switch
+12V Phantom
MLC
-3dB
thermal limit
Over temp.
mute
Mixer /
AGC
Output
stage
Loop output
Current
LED
Current
control
Rectification &
smoothing
30VA
transformer 230V pri. 9-0-9V sec.
Mains input
Power
LED
±12V
MLC control
Input 1
MIC / Line level
Input 2
Line level

4
OVERVIEW
Mounting and Cable entry (shown with lid removed)
CLS1
Knock-outs
Knock-outs
Knock-outs
Mounting holes
(5 X 10mm)
Mounting holes
(5 X 10mm)
Detachable earth lead. MUST
be re-connected before lid is
secured.

5
Controls and Indication
Connections (For wiring details see next section)
Live
Input 1
Mic / Line
Input 2
Line
Neutral
Earth
AC
power
input
Loop
output
Input 3
100V
Line/speaker
Mic /
Line
switch
Phantom
enable
(shown in
off
position)
Input gain
controls
Output current
control
Metal loss
correction
Line Mic

6
CONNECTIONS
All connections are made using screw terminals which accept up to 2.5mm2
(14 AWG) wire. To avoid a single strand of wire shorting to other conductive
parts wires should be stripped no more than 6mm.
Signal Inputs:
Balanced
Microphone
Balanced line
- (Signal cold)
+ (Signal hot)
Screen
- (Signal cold)
+ (Signal hot)
Screen
Unbalanced line
+ (Signal)
Screen
Global
Phantom
Note: Phantom automatically
disabled in line mode
INPUT 1 – MIC/LINE
MIC/line
switch
Phantom off
Phantom on
Balanced line
- (Signal cold)
+ (Signal hot)
Screen
Unbalanced
+ (Signal)
Screen
- (Signal cold)
Screen
+ (Signal hot)
V+ (for remote module power)
INPUT 2 – LINE
V+ is fused 12Vdc for external
modules – screen return

7
+
CAUTION
Heatsink can be
hot. Route
cables away
from heatsink
Loop
Twist feed
wires together
LOOP OUTPUT
100V Line
Mono Low
Impedance speaker
Stereo Low
Impedance Speaker
Left
Right
INPUT 3 – 100V
LINE/SPEAKER
either channel
can be used
+ (Signal hot)
- (Signal cold)
+ (Signal hot)
- (Signal cold)
- (Signal cold)
+ (Signal hot)
- (Signal cold)
+ (Signal hot)

8
Fuse cover
Live
Neutral
Earth
AC POWER
Washer
P-clip
Nut
30m
6mm
Sheathed
3-core
cable
Separate
cables
Cable tie

9
INSTALLATION
System Requirements
The induction loop cable should be installed as detailed in the ‘Designing
Induction Loops’ handbook (available on request at www.ampetronic.co), or
as per specific design instructions provided by Ampetronic.
Tools and Equipment
A magnetic field strength meter (e.g. Ampetronic FSM) or a loop receiver
(e.g. Ampetronic ILR3 or ILR3+) is vital to check that the loop system is
providing the desired level of performance.
As well as tools for securing the unit to the wall, a large flat bladed
screwdriver and hammer are required to remove the knock-outs.
A small flat bladed screwdriver is necessary to adjust the controls and
secure cables into the screw terminals.
A PH2 driver is required to open and close the lid.
Location
The unit is designed for wall or panel installation (or optional insertion into a
1U rack space), with a hinged and detachable lid which is secured by two
Phillips No 2 screws. The unit may also be used free standing.
The location must provide adequate ventilation for the unit.
If the unit is installed in an enclosed environment, sufficient airflow
into the enclosure must be provided through vents, fans or other
means.
Contact Ampetronic for advice on cooling requirements for your installation.
Once the location is decided remove the hinged lid by first unplugging the
earth wire then lifting the lid out of the hinge arrangement.
Use the base section to mark the wall for drilling.
Remove the required knock-outs for cable entry.
Knock-outs are removed from the inside of the
unit as shown by placing a screwdriver on the
edge of the knock-out (opposite the ‘tie point’)
and giving a single sharp blow to the end of the
screwdriver with a hammer or mallet.
Care must be taken during removal so that
internal parts are not damaged.
It is recommended that the AC power feed use a
single knock-out close to the AC power terminal
block and be routed away from other cables. The
loop cable should also be kept separate and use

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its own knock-out. However if all inputs are to be used it is possible to route line
level signals with the loop cable for a short distance.
Once knock-outs are removed fit suitable cable glands with strain
relief or conduit fittings to protect the cable and maintain safety. If
the AC power is fed to the unit using a cable which is accessible
to the user use the P-clip provided for additional strain relief as
well as a suitable cable gland. see Connections drawing.
Any knock-outs left open must be blanked off with a suitable plug. Cable
glands and conduit fittings are available at most electrical suppliers.
The CLS1 is classed as permanently connected apparatus and as
such shall be installed in accordance with relevant building and
wiring regulations.
Connection and Set-up
It is advised that the loop system is initially set up using a local audio source
such as a CD player, which is not connected into any other system. This
avoids the complication of ground loops and feedback etc, whilst the unit is
set up.
The following procedure assumes cables have already been
installed to the site where the unit will be mounted and that
the AC power feed is isolated.
1. Mount the unit in its intended position.
2. Route cables / conduits to appropriate knock-outs or through the back
panel. The black heatsink bar can reach 90°C in normal operation
and may affect cables which are touching it. Cables must be
routed away from this area.
3. Turn all controls fully anti-clockwise.
4. Connect the loop feed cable into the loop terminals. The feed cable
should be tightly twisted. The ‘Designing Induction Loops’ handbook
contains more details on loop and feed cables. The correct design and
positioning of the actual loop is vital for satisfactory system performance.
If in doubt consult Ampetronic for advice.
5. Connect the signal inputs appropriately:
Microphones (balanced only):Suitable dynamic or condenser
microphones. Select phantom power as required. Connect to
appropriate terminals of INPUT 1 (with Mic/line selector switch in the
Mic. position) see Connections drawing.
Line level signals (balanced or unbalanced): From other audio
equipment such as PA system, mixing desk or CD player. If no
microphone is used connect to appropriate terminals of INPUT 1 (with
selector switch in the Line position) see Connections drawing.

11
Line level signals (balanced mono or unbalanced mono and
stereo):From other audio equipment such as PA system, mixing desk
or CD player. Connect to appropriate terminals of INPUT 2 see
Connections drawing.
100V line / low impedance speaker: Connect to the appropriate
terminals of INPUT 3 see Connections drawing. This input may
have a hazardous voltage on its terminals and must only be
connected by a suitably qualified person.
6. Connect AC power to the mains terminal block. Cables entering the
terminal block must be secured together such that in the event
one terminal loosening the conductor cannot come out of the
terminal block and become unsafe. If multi cored cable is used
the outer sheath should be stripped back no more than 30mm to
serve the same purpose. See Connections drawing.
If stranded cables are used strip back no more than 6mm. see
Connections drawing. See also points 5, 6 and 7 in Safety section.
Ensure all relevant tests of AC supply have been carried out before
turning supply on.
7. Turn on AC power feed. The POWER and AGC LEDs will illuminate. If
the LEDs fail to illuminate consult the Troubleshooting section. The
AGC LED will go out after a few seconds.
8. Select one input and apply a suitable audio signal (ideally the FSM test
signal CD applied via a CD player to INPUT 1 or 2, with no connection to
the other inputs). Turn the associated input control clockwise until the
AGC LED illuminates.
9. Turn the CURRENT control clockwise until the CURRENT LED begins
to illuminate. If high frequency oscillation or low frequency hum is
experienced, consult the Troubleshooting section.
10. The loop system should now be providing a magnetic field inside the
area of the loop – use a field strength meter or loop receiver to examine
its performance with respect to:
a. Magnetic field strength. This may vary across the coverage
due to layout, metal loss and loop current.
b. Frequency response. Metal losses tend to increase with
frequency, and may require the adjustment of the MLC
control.
As a result of this analysis, adjust the CURRENT and set the MLC.
Ideally a field strength meter should be used to ensure adequate
magnetic field strength (0.4A/m rms with a sinewave signal) and a level
frequency response (±3dB ref. 1kHz between 100Hz and 5kHz) to
satisfy IEC60118-4. Once the CURRENT and MLC controls have been

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adjusted to the correct level they should NOT need re-adjusting.
NOTE: If the magnetic field strength, or frequency response varies
significantly between the edges and the centre of a perimeter loop this
may indicate significant metal loss. If the standard cannot be met a
redesign of the loop will be required.
11. If not already done so, steps can now be taken to integrate the CLS1
into a PA / mixer arrangement following standard audio techniques. If
any unusual effects are experienced refer to the Troubleshooting
section.
Note: Ideally, each input signal level should be set to just illuminate the
AGC LED with the quietest level of input likely to be used. This will
maximize the dynamic range of the system and ensure satisfactory
performance.
12. Repeat the above procedure for each input used. When adjusting each
input, make sure the signals are removed from the other inputs. This
ensures that all signals are set to equivalent loudness and drive the
AGC properly.
13. Finally refit the lid and earth wire. Secure with the screws provided.
The earth wire MUST be reconnected to maintain safety
TROUBLESHOOTING
POWER LED not illuminated
Check fuse continuity. A 20mm fuse is incorporated into the mains
terminal block. Test the continuity of the fuse using a multimeter. A
spare fuse is provided in the fuse holder
Any replacement fuse MUST be of the same rating and type
as printed on the inner label of the unit.
AGC LED not illuminating
Check input connections.
Ensure that the appropriate front panel control (INPUT1, INPUT2, or
INPUT3) is turned up. Check there is sufficient signal level for the
required input.
CURRENT LED not illuminating
Check the AGC LED is illuminating.
Check that the CURRENT control is turned up sufficiently.
Ensure the POWER LED is illuminated.
Check that the loop cable is connected & terminated correctly.

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Check the loop is not open circuit, short circuit, or connected to earth
(see instability or high frequency noise section of Troubleshooting)
The unit could be overheating (loop current is not delivered if the
internal heatsink reaches a predetermined level). To establish if this is
the case turn the unit off and allow to cool down before turning on.
Ensure that the unit is installed in a location with sufficient ventilation.
Low magnetic field strength
Due to insufficient current or excessive metal loss.
May require a special loop design to achieve acceptable performance,
contact Ampetronic for advice.
Instability or high frequency noise
1. It is possible for the loop cable to be grounded under fault conditions,
resulting in instability which may sound like high frequency noise,
buzz or whistling.
This fault is easy to determine. Simply disconnect the loop cable
from the amplifier and test with a resistance meter between either of
the loop wires and a good earth point such as a metal radiator. There
should be an infinitely high reading i.e. no connection at all. Any
reading indicates a failure of the loop cable insulation and you will
need to either repair or replace the loop cable.
2. Instability can be caused by using poor quality signal cables, long
unbalanced (2-wire) signal runs to the inputs, or by running input
cables in close proximity with the loop wire over an appreciable
distance. Loop amplifiers are capable of delivering high currents at
audio frequencies. If the loop cable is run close to sensitive signal
cables it may be possible to induce a signal back into the input of the
amplifier causing feedback. Cable runs and loop wires should be
kept well apart from each other. To avoid interference maintain a
separation of at least 300mm.
3. Instability can cause the amplifier to run hot and may result in an
overheat condition (see CURRENT LED not illuminating section).
Interference
1. Background magnetic field signals or interference may be present in
any location and may not be anything to do with the loop system.
Monitor this with a loop receiver (such as an ILR3, ILR3+ or Field
strength meter). If the interference is still present with the loop
system switched off, then you need to locate and eliminate the
source of the interference before switching the loop system back on
2. Magnetic fields can induce currents into any low impedance

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electrical path or loop. Audio or video systems with multiple earths
may experience pick up of the loop signal. Check entire sound
system for evidence of loop signal, and trace source of pick up.
3. Under certain circumstances, the loop signal may appear as jagged
lines or hum bars on a CCTV picture. This could be due to running
CCTV (low impedance unbalanced 2-wire circuit) cables in close
proximity to the loop cable. Separate the loop cables to reduce the
effect.
4. Remote (and apparently unconnected) PA systems can sometimes
pick up loop signals. This is usually because the loop cable becomes
damaged (see point 1 of Instability) or induces signals into the
remote system through long unbalanced cables. Always run long
audio signal cables as 3-wire balanced circuits and keep away from
loop cables.
5. See also point 1 of Instability
ACCESSORIES
Details of all products and services provided by Ampetronic can be
found at www.ampetronic.co

15
TECHNICAL SPECIFICATIONS
INPUTS
INPUT 1 (MIC/Line)
Input Impedance: 10kΩper side
Sensitivity: -73/-31dBu
Overload: -37/+5dBu
INPUT 2 (Line)
Input Impedance: 1MΩper side
Sensitivity: -33dBu
Overload: +3dBu
V+: 12Vdc 100mA max
INPUT 3 (100V/speaker)
Input Impedance: 120kΩ/7.8kΩ
Sensitivity: +15/-9dBu
Overload: >+47/>+27dBu
AC Power – 230V version
Frequency: 45-65Hz
Power consumption: 30W
Fuse: T250mA L fitted into
terminal block
AC Power -120V version
(ETL Approved)
Frequency: 45-65Hz
Power consumption: 30W
Fuse: T500mA L fitted into
terminal block.
SIGNAL PROCESSING
AGC (Automatic Gain control)
Dynamic range: 36dB
Output level: -6dBu (±1dB)
Attack: 3.8ms
Decay: 1.7s
MLC (Metal loss correction)
Frequency response adjustment
From flat to +3dB/octave centred
around 1kHz
OUTPUTS
Loop Output
Max. Voltage: 11Vpk, 7.8Vrms
Max. Current: 5Apk, 3.5Arms
Short term peak current: >7A
Continuous max. current:
1.6Arms
Frequency response: 80Hz –
6.3kHz (-3dB)
Distortion: <0.5% @1.6Arms
Min loop resistance: 0.2Ω
Max loop impedance: 1.8Ω
(@1.6kHz)
PROTECTION
Current Limit
Peak current limited to approx.
14A
Thermal protection
The output is muted if the internal
heatsink reaches 90°C.
Approaching this figure the
output is attenuated to a
maximum of 3dB to prevent
nuisance tripping.
PHYSICAL
Dimensions: 200x200x44mm
Weight: 1.8kg
Operating temperature: -10 to
40°C
IP rating: IP20

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WARRANTY
This product carries a five year parts and labour warranty from date of
shipment from Ampetronic. To qualify for the five year warranty, the product
must be registered at www.ampetronic.co (products/warranty), without
which the warranty will be valid for two years only.
The warranty could be invalidated if the instructions in this handbook are
not followed correctly, or if the unit is misused in any way.
DECLARATION OF CONFORMITY
Manufacturer: Ampetronic Ltd
Unit 2, Trentside Business Village
Farndon Road
Newark
NG24 4XB
Declares that the product:
Description: Induction Loop Driver
Type name: CLS1
Conforms to the following Directive(s) and Norm(s):
Directive 2014/35/EU
EMC: EN 55032:2015 Emission
EN 55103-2:2009 Immunity
Directive 2014/30/EU
Safety: EN 60065:2014
Directive 2011/65/EU RoHS
Date: June 2019
J.R. Pieters
Managing Director
Ampetronic Ltd.
UP17201-11