The UV204A or VT-22 is a 250 watt triode with a mu of 23. Maximum frequency for full power is 3 MHz. These brass based tubes were made for RCA by GE and Westinghouse starting in 1923. GE tubes made to be sold directly, were marked PR-4-B. This tube replaced the UV204 and later the UV prefix was dropped and replaced by the 204A about 1931.
Length = 14.38" Diameter = 3.75"
Max voltage = 3000
Max current = 275 ma
Fil voltage = 11
Fil current = 3.85 amps
GE and Westinghouse tubes were supposed to be interchangable as a committee was established in 1924 to share data.
GE UV204As were initally very similar to the late production UV204 tubes. A grove was pressed into the lower base shell to help lock the base insulator into place. The base had no crimp at the top as shown in the first example. The plate of the GE tubes was supported by two flattened rods. The flattened ends of the rods was rivited to the plate and the round end was attached to the inside of a cylinder of metal that was clamped to the plate entrance press. A pair or narrow clamps secured the cylinder to the press and the nut on the lower clamp was used as the attachment to the plate wire. The second later example shows the radiused crimp on the base.
Westinghouse tubes were marked UV204A or the military designation VT-22. Early tubes used the base crimp, but the lip was bent over at an angle as shown on the third example (VT-22). Westinghouse improved on the strength of the plate attachment by using lengths of channel and not rod, The channels were attached to the outside of the plate press cylinder. The fourth example, a UV204A, has a radiused crimp. The plate press was extended as shown in the fifth and sixth examples and the metal cylinder removed. The channels were welded to the clamps. In the fifth example the attachment was to the nut as before and in the sixth example the press is flattened and the wire is welded to one channel. The last 2 examples are marked VT-22 and UV204A, but the the construction is more in line with tubes of the 204A production.