Need help identifying a tube

[Proschuno]

So I found two of these tubes at an antique shop, i know they're directly heated triodes, just want to know the actual model number

They both have numbers written on the glass stem, as follows:

51894
135 91

this one has 'short' written on the bottom

then the second:

52552
GS

[EWBrown]

These appear to be in the 211 - 845 -276A family, all of these have very similar operating characteristics.

The brass base makes it look like a WE 276A, I had a pair of these, but, unfortunately they were too "gassy" to use.
This is a common problem with the brass based tubes, they were never designed to be in use 70 to 80 years after their manufacture.

http://tubedata.tigahost.com/tubedata/s ... 2/276A.pdf

The 211s and 845s have better base seals, and have a much better track record for longeivity.

http://tubedata.tigahost.com/tubedata/s ... /2/211.pdf

http://tubedata.tigahost.com/tubedata/s ... /8/845.pdf

These tubes have a filament power of 10V @ 3.25 amps, plate voltage is in the 1000-1200VDC range.

The two gassy 276As I had would test normally up to about 450VDC, and above 550VDC, the gas would "flash over" and produced a visible
greenish-blue light glow inside the tube.

The one marked "short" probably has a grid to filament short, or perhaps a saggy filament which can intermittently contact the grid.

The plate structure in your tubes look a little different than the 211 / 845, it could be a WE prototype, most likely the 276.

HTH

/ed B

[Proschuno]

Wow, could possibly have prototypes... not that they might be worth anything, but that's a pretty cool possiblility eh?