The RL12T2 is a 1930's/1940's German triode audio output valve. The 12.6 volt heater suggests that this valve was designed for mobile use.
The control grid can be seen to have a small pitch.
The centre of the base is threaded to take a small handle. Our exhibit RL12T1 has the handle still in place. Unlike the similar acorn valves the pins are firmly attached to the Bakelite base and connect to the glass/metal seals with wires. This arrangement does not put mechanical strain on the envelope as the valve is inserted or withdrawn from the valve holder.
The grid supports are copper. At the base the design can be seen to eliminate the long leads associated with pinch construction. Shorter leads means lower inductance and thus a higher maximum working frequency.
Here we have an original valve holder. The nuts and bolts fix the holder to the chassis and clearly the bottom of the holder is separated from the chassis, unlike other valve holders. This construction allows the bottom of the valves to be presented to the outside of the equipment or hidden behind a panel. Opening the panel and holding the handle allows valve replacement to be achieved quickly in the field - important for military equipment.
The identification of the valve holder. W is probably for Wehrmacht.
The whole of the holder identification.
The slot on the right locates the valve to the correct orientation. The spring connections hold the pins firmly.
The top of the holder. The base is 38 mm in diameter and 36 mm tall.
The valve sitting within the valve holder. The spring connections are pushed apart and will thus maintain a constant pressure on the pin.
The complete assembly seen from the side. The metal collar provides a measure of screening.
The thin glass tube envelope is 20 mm in diameter, and 10cluding the base pins is 57 mm tall.
References: Data-sheet & 3002. Type RL12T2 was first introduced in 1945. See also1945 adverts.
