Sensibly equivalent¶ to:
This valve is probably a type AF3. The most prominent marking is the BAL716. The BAL716 stamp showsthat it was made to the German Luftwaffe standard and inspected at that particular office. These codes were in use from 1933 to 1945.
This German valve is marked with the makers name on one side and 'Wehrmacht' on the other. The C78 base was much more popular in continental Europe than in the UK. The Philips owned Mullard company made a range of Ct8 based valves in the 1930s.
See AF3 for details.
The classic metalised envelope is 37 mm in diameter and, excluding the CT8 base pins, is 100 mm tall.
Absolute Maximum Operating Conditions¶
Updated March 12, 2014. shape:classic construction:pinch type:pentode age:1930.1940 base:ct8 heater:4.0v pins:8 pin:1.m pin:2.h pin:3.h pin:4.k pin:5.g3 pin:6.- pin:7.g2 pin:8.a pin:tc.g1