oldest tube(s) in your system

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!

@electricboyo  Regulated Power Supply 25 by Lambda Electronics Corp. Circa 1955 according to Radio Museum. Smells like a battleship. If you know, you know!

I have a pair of Cunningham CX-345 from 1937

1950s sylvania 6SN7s,