RCA black plates with writing on plates

[Tubebandit]

Did they put the writing on for a purpose or am i just seeing things..i just havn't seen this too often. Thanks

 

[H713]

Did they put the writing on for a purpose or am i just seeing things..i just havn't seen this too often. Thanks

Haven't seen writing before... but I have plenty of black-plate tubes that have lots of scratches and other markings on the plates, and I can't imagine that it was caused by a machine. Quite fascinating.

 

[kodabmx]

I have a few of these as well. Always thought it was kind of odd.

 

[PRR]

Working in a tube factory is very boring. They passed the time playing tic-tac-toe on the plates.

 

[smoking-amp]

Maybe the supervisor wanted to see if quality control were actually looking at the tubes.

Or a secret code passed down the assembly line. "Meet you for lunch at the corner deli across from the theater."

 

[pblix]

Reminds me of the engraved messages in the run-out groove on good old vinyl records.

 

[DAK808]

Maybe it marked the beginning or end of a tube production line run ? I have seen that from when i first started getting tubes and wondered what that was about.

 

[6A3sUMMER]

I have seen tubes with marks on the plates, and also writing on the plates, and also on the mica insulators.

Perhaps it makes it sound better. Just like using a green marker pen to mark all the way around the Edge of a CD. LOL.

 

[Tubelab_com]

Maybe it marked the beginning or end of a tube production line run

Having worked an assembly line in my past, I would say a shift change or operator change. I have seen a few RCA's with numbers or letters on the plates.

 

[famousmockingbird]

Maybe it's like a graffiti tag? They may be out of work somewhere and see a radio tube with their "tag" on the plate and say "I made this one". Kinda neat idea

 

[Tubelab_com]

Whose "tag" was this, and what's the odds of finding two of them. Both were in a box of about 500 6AG5 / 6186's that were sorted out of several thousand used tubes that were pulled from military spares. Both tested fine and worked in Pete Millett's Engineers Amp.

I spent almost 5 years sorting through about 100,000 tubes that were given to me. You look through a lot of junk, and find some useful tubes that are useless due to poor handling and storage, and sometimes you find some treasure.

I just traded the WE 5842's and some TFK 12AX7's and 12AU7's for about 500 tubes that will make some serious sound soon.

Then sometimes you just get tired of sorting and decide to blow something up.....death ray tube, or light bulb?

 

[sony6060]

I have seen numbers written on plates. I have no idea what they mean.

 

[Tubebandit]

Thanks everyone.i was thinking that it was from production of the tube, and i have quite a few of these from a thomas organ so i checked a few more and they all seem to have some kind of mark,matching plates before assembly or something.

 

[smoking-amp]

Church Organ? Blessed or Kosher tubes?