DeForest CF-187 Audion
DC Amplifier Triode
1918

The CF-187 was one of the last spherical audions, produced by DeForest in 1918 for the Navy. These tubes were basically obsolete by 1918, and were probably made for replacement use in some of the old Navy audion equipment. This tube, like a small number of others, used dumet in the press rather than platinum. At this time DeForest could not normally use dumet because of patent issues, but patent immunity was given to military suppliers during WWI.

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