Operatic school PA
In the valve era, Bland Radio Pty Ltd of Edwardstown in South Australia made a centralized PA system for schools in Australia.
The central unit consisted of a preamp for a microphone, turntable, AM radio tuner, and a push-pull amplifier, and switches that would switch it to drive speakers located in the classrooms, and out in the school yard.[1][2]
The speakers in the classrooms were a wedge type cabinet design, and were mounted on the wall up high, containing a 20 cm Rola loudspeaker. The "yard" speaker was a 30 cm Rola, housed in a large steel horn,[3] that was mounted high up on either the wall of a 2-story school building,[4] or sometimes on the roof of a school building.
The amplifier delivered a 100 volt line type output that coupled to the speakers via 500 ohm matching transformers, mounted in the speaker enclosures at each locality.
Its Use
Usually this system would be used with the ABC's radio programmes for schools. The teachers would tune the tuner into the programme, and switch it to the appropriate classroom or classrooms. This would sometimes also be done for assemblies outside where the yard speaker would be switched in.
Other Improvisation
Schools that did not have such a system, often played a tape to get the children to march into assembly or set up a radio in the classroom and tuned into the "for schools" programmes. The television was also used, and parents would donate old monochrome TV sets to the school, and they would be stationed in most classrooms, where they would tune into the ABC TV For Schools programmes. The TV set would be repaired if it needed a new valve, but not picture tube replacement.[5]
See also
- ↑ "School public address system Misc Bland Radio Ltd; Adelaide". www.radiomuseum.org. Retrieved 2019-10-15.
- ↑ In the living memory of many former school students who went to school in especially the 1970s
- ↑ Examining of the equipment in private collections in Adelaide
- ↑ Yard Speaker still mounted at one Adelaide school
- ↑ memories of the author, a former student of St Peters Anglican Grammar School (campus now demolished), in Glenelg, Adelaide South Australia 1975 to 1979
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