ID: 
2080
Maker's Name: 
Astor
Where made: 
Australia
c. 1955
Dimensions: 
33 × 13 × 20.5 cm

Superheterodyne domestic receiver.Runs on batteries or from 240 VAC mains. HT 67.5 V, filaments 7.5V. The filaments are in series with the AF output valve at the positive end of the filament string. Its filament is about 7 above earth,so that the grid is biassed about -7 V with respect to the filament.  The valve line-up is: converter 1R5, IF 1T4, detector audio 1S5, AF out 3S4.

Consumption HT 20 mA, filaments 50 mA.

The series filament arrangment has two advantages. First, the grid bias of -7V is provided automatically without any energy loss.

Secondly, the carbon/zinc filament battery has internal resistance and the low current drawn means lower internal loss of energy and less energy wasted over the life of the battery.