This is a simple, wall-mounting, induction-loop amplifier intended for installation by electrical and audio-visual contractors in applications including community centres, board rooms, churches, interview and meeting rooms, classrooms. Despite it’s compact discreet enclosure, it has extensive input options, a powerful output and the mounting and cabling features ensure that installation is convenient and tidy in any environment. It can serve an area of over 400 metres square.
The unit is wall-mounted in a similar fashion to an alarm control panel. Cable routing ‘knock-outs’, 20mm diameter, are provided for routing cables into the enclosure, two on the top edge, four on on the rear face, four on the bottom edge. On the front a cut-out reveals a panel with three LED indicators, amber to show activity of the AGC, green to show current is flowing through the loop and green to indicate power.
The cover can be hinged down after the removal of two torx screws to reveal a printed circuit board and a power-supply transformer with a terminal-block for connection of the AC supply. All input cable connections and loop output are made with screw terminals mounted on the side of the PCB. A label on the rear of the hinged down cover details the connections. There are four independent inputs. Input one and two offer balanced microphone or balanced line or unbalanced line. Input three can be balanced or unbalanced line level or configured for an unbalanced stereo signal. Input four is isolated, for unbalanced 100V line or low impedance mono or stereo speaker feeds. The alert inputs can be used for events such as doorbell, telephone and fire alarms. The alert one input when energised, turns down the other inputs and produces a 520Hz square wave tone on the loop. Alert input two is a pair of contacts which, when shorted, turns down the other inputs and produce a pulsed 520Hz square wave tone on the loop. Six controls on the PCB are adjustable with a screwdriver: level controls for inputs 1, 2, 3, 4, metal loss correction and loop drive current.
The CLS2 is designed for single turn loops. Maximum cable length is dependent on cable type and on the application. As a guide, the maximum cable length for normal use, should be 91 metres of 4mm sq.
Input 1: -73dBu to -37dBu / -31dBu to 5dBu, microphone/line, 20 kohms/10 kohms balanced/unbalanced. phantom power voltage +12V.
Input 2: as Input 1 above
Input 3: -33dBu - 3dBu , 1M ohm.
Input 4: 14dBu - 47dBu / -9dBu - 27dBu, 120k ohms / 7.8kohms for 100V line / low impedance respectively.
Alert input 1: 5V- 24V AC/DC.
Automatic gain control (AGC): Better than 36 dB dynamic range, optmised for speech. Response: 80Hz to 6.3kHz +\- 3dB. Distortion: less than 0.5% THD +noise, 1kHz sine wave, 2.33A RMS. Drive voltage: Better than 6.4V RMS, 9.0V peak. Drive current: More than 4.6A RMS, 7.0A peak, continuous 1kHz sine wave. Drive current, short-term peaks: more than 7A RMS, 10A peak. Loop resistance: 0.2 - 1.3 ohms. Metal loss correction (MLC): 0 to 3dB per octave frequency correction (1kHz remains constant). Power source: 230V 30W, 45-65Hz. Dimensions: 200 x 200 x 44 (w x h x d)mm. Weight: 1.8kg.
Included accessories: ‘Loop present’ logo, P-clip and fixings.
Optional accessories: The RM-1U rack tray will take one or two units. The BPL-1U will be required if only one unit is fitted.
RM-1U Rack Mounting Tray
The RM-1U is a single-unit rack-mounting tray which will take up to four Ampetronic devices, depending on width, or blanking plates. The BPS-1U Short blanking plate takes up one quarter of the width. The BPL-1U Long blanking plate takes up half of the width. Loop drivers and other accessories can be fitted up to the total width. Blanking plates should be ordered to fill gaps.