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OS70/1750 datasheets

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I'm searching for the data sheets of the Tungsram OS70/1750 tube. It's said they are equivalent with the 828 but I questioned that because filament of the OS70/1750 is rated at 7,5 Volt 2,5 Amperes (radiomeseum.org) while the 828 is rated at 10 V 3,25 A.
I searched the internet but could not find a data sheet for the Tungsram.
 
I promise you that you didn't see this before.
This is a page from the 1941, July issue of OZ, the Danish Magazine for Radioamateurs.
What is says about OS70/1750 is basically:

OS70/1750 is a modern universal Pentode for work as a modulator or TX tube until 4 meter (~70MHz) with a high efficiency.
2 tubes in Class AB1, Push-Pull yields 300W LF-output and by applying NFB the distortionfactor can be kept below 1%.

No curves, sorry :D

rgds,

/tri-comp
 

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  • Tungsram.pdf
    634 KB · Views: 123
Thx Tricomp, you also answered my next question for curves. Yes I'm planning to build a PP with those tubes. I would like triode connected but no triode curves to be found. So penthode connected is what is done in the schematics I saw till now ( STC 250 watt ) but I would like to do ultra-lineair with a 43% tap. BTW 300 Watt I don't need at all.
To get back on my original question, the OS70/1750 is equivalent with the 828 only filament is 7,5 V 2,5 A. Looks like Tungsram did a better job for getting the tube into emission than the RCA peepz.
Btw put the schematic with the post. It can be found at Dennis Grimwoods site Tubes
 

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  • STC250Aa.jpg
    STC250Aa.jpg
    310 KB · Views: 219
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