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This is the latest version of the unit first introduced in 1972. The purpose of this unit is to sense the level of sound produced in an entertainment venue from, say, a disco or a band, to provide a warning indication that the sound level is at or exeeding agreed limits and, if these indications are ignored, to cut the power feeding the amplification equipment.

The front panel of the main unit has a 3 colour bargraph LED display showing sound pressure level, and LED indication of when a power trip has occurred and what caused the trip, indication of what weighting is selected (‘A’ or ‘B’) and a ‘warning’ LED which indicates when the pre-set ‘trip’ level is being approached. This warning indication is also shown by an external lamp in a yellow/orange globe (the Electronic Orange!). Switches on the front panel are for power to the unit, reset (for manual mode only) and ‘mode’ which is a key operated switch which selects ‘manual’, ‘auto’ or ‘override’.

The acoustic input is via a supplied cable mounted measurement grade condenser microphone which can be mounted remote from the main unit. Disconnecting the microphone will trip the unit. An auxiliary switch input (normally closed) enables the unit to be operated from, say, a fire door contact. The GA904 is supplied complete with 10 metre cable, microphone and remote warning light assembly. Installation should be by a competent electrician.

Manufactured by Castle Group Ltd.

Technical Specification:

Trip range: 75dB to 112.5dB in 2.5dB steps switch selectable, ±5dB calibration control (factory set)
Warning range: –3, –6, –9, –12dB below pre-set trip level, switch selectable
Trip time: 1 sec to 10 secs user adjustable (potentiometer)
Mute time: 20 secs from beginning of trip time
Power switching: The unit will switch a 240v 30A load
Frequency weighting: A or B in accordance with IEC651 Type 2
Outputs: AC 1V RMS for F.S.D. output impedance <100ohms
DC 3V for F.S.D. 50mV/dB output impedance <100 ohms.
Both the above are short circuit protected
Aux power out +12 0–12V for accessories.
Power requirement: 200/240v 50/60Hz
Temperature range: –10° to +50°C
Dimensions: 200(w) ×240(h) ×60(d)mm
Weight: 1.5kg
  Description Price £
ex. VAT
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CASTLE GA904 ELECTRONIC ORANGE   Stock code: 42-666
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