Specifications for the UV-201 tube
 

Does anyone have a spec sheet by chance for a UV-201 tube? Not the UV-201a. The UV-201 is an earlier tube with a 1amp filament vs the 1/4 amp filament.

Basically I need to know the Gain characteristics of this tube. I'm wondering if it would be different than the 201a being and earlier tube.

Thanks -I'm gonna post this on the Tube forum as well.

Steve

Did you mean UX-201? Specifications, apart from filament current to achieve emissivity is similar, although the interelectrode capacitance is slightly different. the 1/4 amp UX-201-A as I recall, is so designated becuase it uses an alkaline-earth coated- filament versus the non-coated tungstun filament. The non-coated tube will draw considerably higher current in order to achieve equivalent emission to the 'A' type tube. Even as early as 1932, RCA was manufacturing alkaline-earth coated filaments. They often abreviated the typed designation to, simply, the 01-A. This was also done to distinguish RCA tubes from other manufacture type numbers that did not employ the alkaline coating.

From RC-10, published 1932

Characteristics: UX-201-A (alkaline-coated filament, 3 electrode) TRIODE

Filament Voltage (D.C.) 5.0 volts
Filamanet Current 0.25 amps
Plate Voltage 90 typ. 135 max volts
Grid voltage -4.5 to -9 volts
Plate current 2.5 to 3.0 milliamps
Plate resistance 11000 to 10000 ohms
Amplification Factor 8
Mutual conductance 725 to 800 Micromhos
Grid-Plate capacitance 8.1 uuf
Grid-filament capacitance 3.1 uuf (3.5 uuf for type 01)
Plate-filament capacitance 2.2 uuf (2.4 uuf for type 01)
Bulb type S-14
Base Medium 4-pin

Note: tube must operate in VERTICAL position. Tube is suceptable to microphonic disturbances. Filament is designed to operate from a 6 volt battery and a fixed or variable resistor must be employed to reduce this to 5 volts. The tube is designed for use an interstage audio or rf amplifier or as a detector.