The TT15 is of all glass construction and dates to the mid 1950's. The prototype was the VX3087 and the maximum operating frequency was 150 MHz.
The TT15 is a dual transmitting tetrode, with narrow short pins set equi-spaced around a circle. A metal base plate with a locating spigot protects the evacuation pinch. A part height screening sleeve also acts to hold the spigot plate in place.
This RF Power Double Beam Tetrode is of the American pattern with two separate valves within the envelope. The anode forms a rectangular box that encloses the valve electrodes. The screen grid is presented as a common connection for both valves.
The twin beam tetrode sections.
The bright beam plate can be seen within the anode and both inner grids have copper supports.
The B9G base pins.
The wide glass tube envelope is 40 mm diameter and excluding the B9G base pins, is 67 mm tall.
References: Data-sheet & 1040. Type TT15 was first introduced in 1954. See also1954 adverts.
