GE Experimental 201A On UV-199 Base

This is a unique experimental tube produced by General Electric in the mid 1920's.  The internal structure is that of a UV-201A, but the base is that of a UV-199.  The only markings on this tube are the GE logo etched into the glass, and the "UV-201A" written in ink on the base.

Presumably, GE was investigating a tube that could be substituted in radios designed for the UV-199 type tube that would give improved performance.  As with the WL-112, it would appear that the potential market for such tubes was limited, and they never entered regular production.

I know of one other such tube in a private collection.  There is also a version that has a Bakelite base, and no tip.