Sensibly equivalent¶ to:
This example of the Cossor 210LF dates to after 1931 when the 'New Process' was introduced. It is an improved version of the 1929 valve.
The 210LF was the basis of VR21, CV1021 and AR9
Cossor describe the 210LF in their 1935-6 manual as a valve primarily intended as the first low frequency (AF) stage.
The 210LF is recommended as being useful as the driver for a class B stage in combination with the Cossor 220B. See PM2B as similar.
Full output must not be expected from the class B valve when the 210LF is used as a driver, but the highest economy in anode current is obtained, combined with adequate volume for all domestic purposes.
Looking beneath the silver gettering the box anode can be seen. The ends of the grid supports are splayed out to attach to the supports embedded in the pinch. The filament is oxide coated and can be seen to get wider as it travels up the valve. This looks like an example of the Cossor 7 point suspension.
The balloon envelope is 41 mm in diameter and, excluding the B4 base pins, is 82 mm tall.
References: Data-sheet, 1043 & 1040. Type 210LF was first introduced in 1929. See also 1929 adverts.
Absolute Maximum Operating Conditions¶
Updated December05, 2021.