Help Identifying old tubes

[Duthu]

Hello All,

I am hoping someone here can help me identify some tubes that I came across while cleaning out an old warehouse. The box they are in says "GE Electronic Tubes", though they are individually boxed in white boxes labeled 718116. When you open the individual tubes there is no reference to GE or any other standard tube markings or identifiers.

The label on the tubes read:
718116
(SPL)
(07187)
G 69 14

My best guess at the moment is that the tubes were purchased by Sperry Corp and the old labels were removed and substituted for internal markings. The reason I say this is that is if you google (SPL 718116), you will find an ebay listing for Sperry Gyroscopic Tubes and I do know Sperry (and other companies) would purchase and rebrand tubes. In one of the photos you will see a "foggy" area on the tube, this is on everyone of them which leads me to believe it was mass rebranding. That being said, this is all speculation which is why I am asking the question here.

Any help is greatly appreciated. See attached photos.

 

[arts]

Both triode sections appear to be physically identical. I'm going to guess a 6SL7,as they commonly used a round plate structure. How many did you get?

 

[Tom Bavis]

Yes, test it as a 6SL7 and see what you get.

 

[primosounds]

Sure looks like a 6sl7 although it maybe a 12sl7 which looks the same but different heater voltage.

 

[Duthu]

Thanks for all of the help and pointing me in the right direction. Any thoughts on them being 1950's era Sylvania 12SL7 GT?

The way the heater metal is stamped and formed is identical and the foggy area where the labels were removed match perfectly to where/how Sylvania marked their tubes. Reference: https://www.ebay.ca/itm/NOS-NIB-Syl...636334?hash=item1a38e44f6e:g:JqcAAOSwridZ984A

Basically I am trying to get a realistic price of what I can sell the 100+ I have for.

 

[kvflyer]

I would test/try them as a 6SL7 first. If that is what they are, the filament should be orange. You don't want to try 12 volts on the filament if they are 6SL7 tubes. If so, you quantity may well go down by one.

 

[EastPoint]

If they test fine as 6SL7s, good. If they all test really weak, like 25-50% on both sections, they're probably 12SL7s. If you test them as 12SL7s and the filaments glow really brightly, they're 6SL7s. It'll be pretty noticeable.

 

[GordonW]

I would test/try them as a 6SL7 first. If that is what they are, the filament should be orange. You don't want to try 12 volts on the filament if they are 6SL7 tubes. If so, you quantity may well go down by one.

Indeed, that's the best common sense answer! You can always turn up the heater voltage later if it doesn't light up properly or work to spec- but it's hard to un-blow a heater that's been subjected to twice it's regular voltage!

Regards,
Gordon.