This author has scanned all the magazines that appear on this website and many had very interesting articles like this one that Fin Stewart submitted in Vol. 14, No 2, April, 2012.

Fin Stewart quote: “I picked up a mint copy of the book: BTH, Reminiscences – Sixty Years of Progress published in 1946, and found this amazing photo- a tube I don’t think any one may have known about.”

“The caption reads: First radio valve made by Mr. R. C. Clincker of 1915. The tube looks to be a copy of the single-wing DeForest Audion but with bayonet (B22) bases at each end. Also, the photo looks like an artist’s drawing, but with a tube as rare as this, who would argue.”

“Tyne’s (Saga of the Vacuum Tube), p. 215 refers to the BTH Audion but not Clinker. He has a sketch of a tube like the DeForest Audion. I picked up one of these up in London in 1984 and attach a photo. You can just see the logo at the top center on the left in front of the plate. You might like to share my find in an upcoming TCA bulletin.” End of quote.

The 2 top large photos are the exact photos that Fin submitted. The large photo on the top left is the BTH audion that Clinker made in 1915 that appears in the BTH book. The B22 bases on this tube are the same size as what Fleming used for many of his later vales and would fit into the same sockets.

The large photo on the top right is the same tube that Fin submitted, in a contemporary picture, that appeared in the TCA magazine and he stated he picked up in London in 1984. As can be seen in the photo, the BTH logo is etched onto the bulb towards the upper left with part of the right side of same being in front of the plate. This is identical to the small BTH logo picture at the beginning of this text. It has the normal candelabra screw base, 2 wires for the grids and plates, 2 wires connecting both ends of the double filament loops in the base.

Tyne’s Saga does not give many details on the BTH audion but does submit a sketch of a BTH Audion I assume was not in his collection nor does he state that BTH was etched on the bulb. BTH dropped the entire DeForest audion concept for the normal reasons, too expensive and hard to make.

R. C. Clinker is confirmed to be a head research engineer for BTH at the Rugby location.

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Sources:

Stewart, Fin: Total credit to Fin for finding and submitting the article to TCA magazine.

Sibley, Lud: Credit to Lud as editor of the TCA for placing the article in the TCA magazine.

H. A. Price-Hughes, BTH, Reminiscences: 60 Years of Progress. 1946.

Tyne, Gerald, “Saga of the Vacuum Tube”., page 215.