The first type of remote cut-off Tetrode to be manufactured by RCA. Originally called UY-235, abbreviated to 35 in 1932. Manufacturer: RCA Radiotron Co., Inc. Harrison, New Jersey, USA. 2.5 V indirectly heated cathode.

The remote cut-off or variable-mu tube was developed by Ballantine and Snow, working for the Boonton Radio Corporation. The first commercial type was the 551 manufactured by Arcturus, the UY-235 made by RCA was virtually identical.

Physical Description

Conical bulb (with top cap) with 5 pin UY style base.

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