Most of the D3A's out there now are Siemens yet there doesn't seem to be any data produced by Siemens themselves. There are sheets by Philips and Telefunken but they differ. Anybody got a Siemens pdf lurking on their hard drive?
In my Siemens Tube Pocketbook from 1960 is only the amplification factor different from the TFK data , 85 Siemens to 80 TFK and Philips .
My great Siemens Handbook 1963/64 is without D3a .
My great Siemens Handbook 1963/64 is without D3a .
My Siemens 1963 "Special Quality Tubes" has 12 pages for the 7721 which I believe is the same tube. The problem is that I don't have a scanner and would have to break the binding to get it to lay flat. It even has triode curves. 
Thanks 604. I was looking at the pages for triode connection. The Telefunken curves are considerably better than the Philips, which makes me wonder where the Siemens stand in relation. I was hoping I wouldn't have to do my own curves for them.
HollowState, thank you too! I didn't think of Siemens and the 7721 together . It's the triode curves I'm after.
HollowState, thank you too! I didn't think of Siemens and the 7721 together . It's the triode curves I'm after.
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