Identifying 211 VT4C or 284D Western Electric?

[welli247]

Hi,
I recently acquired from a relative these two old tubes. searching the internet they look very similar to Western Electric 284D or alternative Amperex 211 VT4C?

Is there any experts who can identify these from internal construction. Photos attached

Thanks!

 

[HollowState]

Nice pair of tubes. Unfortunately the only way to take an educated guess as to what it is, is to examine the grid wire spacing. It is virtually impossible to photograph enough of the grid to easily determine this. So it must be done in person by looking at a steep angle. A WE 284D (aka 845) has a larger spacing between grid wire turns compared to a 122/VT4C or 242A which is about an eighth of an inch or slightly less. (I have all of these) The construction that supports the plate may give a clue about the manufacture, but not really what it is. And, of course, testing it is the real way to determine it's type.

 

[6A3sUMMER]

Get a filament transformer, a Variac, and set up to measure the filament voltage and the filament current.

When you set the Variac slowly, stop at each volt across the tube and wait until the current stops changing at that voltage, then raise it another volt, and wait till it settles . . .
Slowly warm up the filament, volt by volt, if you safely get to 10V and 3.5 Amps, then it is probably a 211 or 845.
But suppose you get something like 3.5A at 8V, stop, you have a different tube.
Or suppose you get 2.0A at 10V . . .

There might be a different type of tube that is a look-alike, but that is not rated at 10V 3.5A

 

[Chris Hornbeck]

I can say for sure that they're not the usual GE VT-4-C, or WW2 era RCA VT-4-C. Also not United Electronics CUE.

All good fortune,
Chris