Cranford Controls

VSO Base Sounder 24 Vdc – EN54-3 Approved

Product Overview

The VSO base sounder is for use with conventional fire alarm systems, including two wire (SAV-WIRE®) and is designed to accept most leading detector bases and offers a cost-effective solution to sounder installation. The low profile sounder is supplied with 32 tones, along with a two stage alarm override which is activated by a third negative wire from the fire panel.

All tones have been selected to comply with the latest sound patterns and frequencies used throughout the world. All tone options are fully synchronised. This sounder has been fully approved to EN54-3 by the LPCB and VdS on tones 1, 3, 11, 25 and 27.

When a detector is not fitted to the sounder, a blank cover plate is available so that the unit can be used as a standalone sounder.


  • 32 tones plus a selectable override tone
  • Switch selectable volume control designed to work with both conventional and two-wire (SAV-WIRE®) systems
  • Fully approved to EN54-3 by LPCB and VdS
  • Modern ultra low profile for discreet mounting
  • Designed to accept most leading detector bases (contact us for colour options available)


Voltage range (Vdc) 18 – 30
Number of tones 32
Operating frequency (Hz) 440 – 2900
Temperature range (C°) -20 to +70
Monitoring Reverse polarity
Protection rating IP21C
Boxed weight (kg) 0.11
Body colours available White or Ivory (ABS fire retardant plastic)



Volume Setting High Med Low
Sound output, typical (dBA) 93.8 90.4 88.7
Sound output, anechoic chamber (dBA) 91.2 87.7 86.2
Sound output, reverberation chamber (dBA) 110.9 108.1 105.4
Max. current consumption @ 24Vdc (mA) 12 8 6
Power consumption @ 24Vdc (mW) 288 192 144


Part Numbers

507-001 White body, 32 tone
507-020 Ivory body, 32 tone
507-006 White cover plate *
507-030 Red cover plate
 507-029 Ivory cover plate

*approved part number 116-009