oldest tube(s) in your system

I used to run RCA mono-plate 2a3s made before 1936.  Those are good sounding tubes.  A friend runs extremely rare and old 252 meshplate anode tubes made in the 1920’s that pre-date the 300A.  He rarely plays the amp because those tubes cost well north of $30,000 a pair.

I run some globe 866 mercury rectifier tubes, probably made in the 1930's.

Pair of 1945 JAN Sylvania 6SN7W and a Tung Sol round plate black bottle 6SN7 of unknown vintage in the front end of a Cary Audio 300B SEI LX20. The Sylvania’s are the best sounding pair of 6SN7s I own, and I own plenty! In fact, too many. 

@xenolith  The neon actually fires when DC is switched on. It regulates the screen voltage on the screen grid of the 5693 (6SJ7) driver tube. The output voltage is set by a resistor network on the driver's grid. 

@noromance Beautiful piece of gear!  Thanks for sharing the photo.  Love the eye tube too!  Does it ’close’ (or is it open?) at 325v?

@noromance that’s awesome!  Thanks for the reply and especially for the photo of that sexy critter!  Wonder how many provide such an awesome power supply to  their otherwise factory power supplied gear.  I’m in awe of may of you for your talented tube gear applications.  Fremer used to refer to "hair shirt audiophiles"; ha,  we don’t wear it if ain’t worth it!

Guys (going out on a limb here) like you make me feel tame and timid audiophilia-wise.  Will be notifying mrs. x of my audiophilic timidity shortly :).

@larryi yours and your friend’s amps; wow!  Any chance for a photo of the $30k per pair tube amp unicorns?

Thanks all for a fun thread!