oldest tube(s) in your system

Wow; 1936.  Pre-WWII.  Others have too.  Amazing.

Did vacuum tubes precipitate WWII?

I do have a WWII era military rectifier, but prefer a somewhat later GEC cup base U 52; I run a set of GEC KT 66s that I bought NIB NOS some years ago for my "vintage" system. Most of the tubes in my two systems are somewhat more modern- 6h30s from the late ’70s. I don’t know how old the Russian 6C33C I use in the Lamm amps are; I suspect they are also late ’70s. Those mercury vapor tubes are very cool, but have not used them. 

I recently retubed the main system but have been having some noise crop up- I think it may be the line stage (Veloce Lithio upgraded by Vytas)-- last time I had this issue, I cleaned the battery contact plates and the noise disappeared.

I’ll sort this out soon, I just need time and patience since I have a full complement of fresh tubes for the Lamms, along with NIB old stock Tele 12ax7 ribbed plates, which I prefer for these amps- they give it a little "grit" which makes them less sweet and lends a gravitas to the amps. I run them with extremely efficient horns. 

Trying to locate a matched quad of early production 6h30 reflectors is not easy or cheap; to my guesstimate on hours, they should still be in good fettle, but we’ll see. 

https://forum.audiogon.com/discussions/oldest-tube-s-in-your-system/post?postid=2839009#2839009

Awesome looking DC power supply.

I'm guessing it was manufactured somewhere between 1930 and 1950?

The system keeps getting older!  Replaced the 1958 Western Electric D-getter JW 2C51 with 1957 NOS+ testing General Electric 5-Star (white) 3-mica 5670...but then replaced those with 1951 NOS/NIB Heintz and Kaufman labeled General Electric 3-mica 5670. 

These, and their factory mates, will be the last and only tubes run in our modified Dodd Battery Powered Preamp (by me anyway) as they've been the most positively transformative tubes I've ever heard.  Just Wow!