The Type 46 is an American tetrode audio amplifier and dates from 1930. The data suggests use as a class B amplifier and triode connected as a class A amplifier. Given the problem and distortion of secondary emission in the tetrode, and its normal use in class C with tuned circuits where the secondary emission is not an issue, a tetrode designed for audio use would not be overly successful. As a triode it would be much more suited to audio power amplification.

The filament is oxide coated ribbon. The control grid is wound on copper supports for better heat dissipation and the screen grid is clearly seen in the picture.

Seen through the top mica the coated filament loops and their support springs become visible.

Looking directly down on the top mica the grids can be seen. They are clearly shaped as the end supports are single rods and across the broad face of the anode the grid wires are straight and parallel to the anode.

The classic envelope is 51 mm in diameter, and excluding the UX5 base pins is 118 mm tall.

 
Pin Connections

UX5	1	2	3	4	5
	f	a	g1	g2	f

 
Absolute Maximum Operating Conditions

Tetrode	Vh	Ah	Va
	2.5	1.75	400

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 10 March 2008 {find valves by name}