Author Options:

Vintage Vacuum Tube? Answered

I have a vacuum tube from my collection here that I would like to test. It says on the box International, Electronic tube, GTE, Sylvania, And what appears to be 12Z - the last letter or number I don't know its either a 1 or a capital i, 12Z - I or 12Z - 1. It has 12 pins, 3 of which are not connected to anything, I can see that visually. Any help would be appreciated.



Best Answer 8 years ago

It's a 12z1. I was able to find it listed in my tube tester chart, but unable to determine what is does yet.
Look at this page to decipher the number. Read paragraph #1.

They probably should be within 20% for the tube to work as intended, but we all know that WE never use things as intended do we?

You'll have to get it up in the hundreds though to get anything out of it so be very careful and if you don't think you can do that safely then store the tube away until you get a little more experienced.

There are other tubes that don't need 700 v. to work.

Look at this
It would be a good project to start out on in tubes. HV transformers are expensive and this one doesn't use a hv transformer and the tube is cheap.
Good luck.

It may not be a 12z1 afterlooking at my chart again which is a scan of the old document there might be a number after the second one. Does it look like there might be another number after the 1 on your tube? I can't find a listing anywhere for a 12z1 but I can for 12z2, 12z3, 12z5. I also couldn't find any listing for any other number that had a 1 after the letter, but lots that had 2,3 etc.

I would say its probably a capital "i" it looks different then the 1. That's all it has on it though.