CLS2  Loop Driver CLS2 Loop Driver
5 stars - "Review for CLS2 Loop Driver" This CLS2 Loop Driver is the best System Types I have tried.
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  • CLS2  Loop Driver - Image 1
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CLS2 Loop Driver

Product ID: CLS2
Brand: Ampetronic

View or buy the System Types Assistive Listening Systems - CLS2 Loop Driver from Ampetronic to discover other options and shipping details.


CLS2 Wall Mount Perimeter Induction Loop Driver, 4.6Arms, for areas up to 400m sq

The Ampetronic CLS2 is the second unit in a series of induction loop drivers aimed at the demands of the electrical and audio-visual contractor.

Designed for simple discreet installation, the CLS2 is the most capable driver in its class. The amplifier is very compact, yet the most powerful unit available designed specifically for wall mounting. All connections and controls are secured behind a tamper resistant, hinged, detachable cover. Combined with its small size, the range of mounting and cabling options ensure that installation is convenient and tidy in any environment. Input options are extensive, with four independent inputs for balanced microphone, balanced and unbalanced line, low impedance and 100V - line speaker systems, plus priority alarm, doorbell or telephone connections.

Backed by Ampetronic’s standard 5 year warranty and comprehensive support services, the CLS2 is truly fit and forget.


  • Quick and simple to install

  • Area coverage to >400m2

  • Highest power loop driver in class

  • 4 Independent configurable inputs

  • Wall mounted

  • Metal Loss Correction

  • 5 Year warranty

  • Cabling and controls behind tamper resistant cover

  • 2 Priority alarm inputs

  • Free Technical support

Applications include
  • Community centres

  • Board rooms

  • Churches & places of worship

  • Interview rooms

  • Meeting rooms

  • Classrooms

The CLS2 enclosure is designed for simple, permanent installation, with secure lid protecting connections and controls, while leaving operation indicators visible. The case is designed to make access simple, and to ensure the amplifier can be installed in the most constrained spaces.
Designed for vertical panel mounting using 4 screws (6 holes provided). Template for screw placements provided. The CLS2 is compact enough to fit on a 1U rack tray with feet removed.
Enclosure access
Hinged lid, secured by 2 Phillips PH2 screws. Lid can be removed completely if required, for ease of access, or if there is no room to hinge the lid forwards.
Cable routing
Knock-outs (diameter 20mm) are provided for routing cables into the enclosure. 2 on the top edge, 4 on the rear face, 4 on the bottom edge, providing excellent installation flexibility.
Cable connections
All input cable connections are made with screw terminals mounted on one side of the PCB. Mains power connections are made to a chassis mounted screw terminal block. Loop connection is made to a screw terminal pair mounted on the PCB. Cable connections are illustrated on a detailed label on the case interior.
3 LED indicators are visible with the case open or closed:
  • AGC Amber LED lit when input signal is activating the automatic gain control

  • Current Green LED lit when current is running in the loop

  • Power Green LED lit when the unit has power

Five controls are located to be accessed only with the lid open, all screwdriver adjustable.
  • Level controls for inputs 1, 2, 3 and 4

  • Metal loss correction

  • Loop drive current

Product InformationRelated ProductsDetails / Downloads

Perimeter Loops – Area Coverage (maximum)

The CLS2 is designed for perimeter loop applications.

Room aspect ratio




Maximum area coverage m2




For any Induction Loop System, area coverage is dependent on several factors. Please check these assumptions and contact Ampetronic for advice if required:

  • The loop is 1-2m above or below the receiver height

  • There are no metal structures in the plane of the loop

  • There is sufficient voltage to drive the cable length – check table below.

Maximum Cable Length

The CLS2 is designed for SINGLE TURN loops for optimum audio quality:

  • Loops with DC resistance from 0.2Ω

  • Impedance up to a maximum of 1.3Ω

Maximum cable length is dependent on cable type and on the application.

Cable type

Maximum Cable Length (m)

Normal Use

Transient Speech

1.0mm2 copper



2.5mm2 copper



4.0mm2 copper



1.8mm2 flat copper tape



CLS2 Specifications


Input 1

Balanced Mic, balanced or unbalanced line
Input impedance 10kΩ per side
Min level (MIC / Line -73dBu / -31dBu
Max level (MIC / Line) -37dBu / +5dBu
Phantom voltage MIC only +12V

Input 2

As input 1 mic level

Balanced mic

Input impedance 10kΩ per side

Min level (MIC / Line -73dBu / -31dBu

Max level (MIC / Line) -37dBu / +5dBu

Phantom voltage MIC only +12V

Input 3

Balanced or unbalanced line, expansion port
Input impedance 1MΩ per channel
Min level -33dBu
Max level +3dBu

Input 4

Isolated 100V line or low impedance mono or stereo speaker
Input impedance 100V Line / spkr 120kΩ / 7.8kΩ
Min level 100V Line / spkr +14dBu / -9dBu
Max level 100V Line / spkr >+47dBu / >+27dBu

AC power input supply

230V 30W 45-65Hz
120V option available
Connected via chassis mounted screw terminal block

Input fuse - 230V 

Input fuse - 120V 




Drive voltage

>6.4Vrms - 9.0Vpk

Drive Current

Continuous 1kHz sine wave >4.6Arms 7.0Apk
Short term peaks >7Arms 10Apk

Minimum Loop Resistance


Maximum Loop Impedance



Frequency response

80Hz to 6.3kHz ±3dB



Automatic Gain Control

(AGC) Optmised for speech. Dynamic range >36dB

Metal loss correction

(MLC) 0 to 3dB per octave frequency correction (1kHz remains constant). Control mounted on PCB.



Natural convection


IP20, -10ºC to +40ºC


W, H, D: 200mm, 200mm, 44mm




Wall mounting, secured by 4 screws


Ashton Audio
 in conjunction with Ampetronic can design your induction loop system for you.  Simple induction loop designs are free, complex array systems will be charged for at a nominal rate.  You can request a design through our 'Contact Us' Enquiry Form.
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