i i got a box of tubes today many of them are western electric with engraved bases. i found one batch that was kind of intersting they are 262A tubes i got a box of these only One has the Western electric engraved in the base. i looked them all over carefully and they are Completly identical in every way to the one that is marked the internal structure and everything except all the others have a etched number like X4-4-632 on the glass the last 3 digits are diffrent on every tube.
i also got a box of tubes with numbers like X57720 and X69892. these are 4 pin look very much like a 01a inside did western electric use that form of code on their tubes too. there are no other markings on glass or bases on these. just trying to figure out what they are.
i also got a box of tubes with numbers like X57720 and X69892. these are 4 pin look very much like a 01a inside did western electric use that form of code on their tubes too. there are no other markings on glass or bases on these. just trying to figure out what they are.