[ServinginEcuador]

I have been reading a lot of good things posted here about this Tung Sol 5751 tube, but have been unable to find out any specific info about it. Does it have grey or black plates? What years were the good production years? Are there any other designators/codes to distinguish between those "good" tubes and "other/bad" tubes?

Thanks and Lord Bless,
doug

 

[eric343]

It's a greyplate 2mica tube, some/all have longer than normal plates.