Thanks, Lord Soth, that's a huge help. I've never dealt with that eBay seller before, but I didn't read any negative reviews re: inaccurate or deceptive descriptions.
I'm not getting a real tubey sound from these after about 25 hours, but I'm assuming these are silver shields (the vertical piece with the A4 9L stamped on it?). I definitely like what I'm hearing. Don't the later versions have a very thin getter support, like these?
Also, re: the =\= manufacturing symbol, is that literally =\= stamped or printed somewhere, and if so, where would it normally appear? I'll have to pull mine tomorrow and have a closer look.
Anyway, I really appreciate you sharing your knowledge. I've learned a lot about tubes in the past couple months, but nowhere have I found info like this re: Siemens tubes.
Yes the photo in your link shows the single getter design.
These are newer tubes made in the late 1970s to 1980s.
There is no definite rule as to where the =\= symbol might show up.
The =\= symbol sometimes appears on the internal metal plate which you asked earlier.
For older tubes, it is etched and is usually very faint.
You would have to hold the tube up against a light source and rotate the tube slowly to locate it.
It is usually near the base of the tube, in the area slightly above the tube tube pins.
(By way of analogy, it is akin to holding a currency note against a light source to check out the security features.)
Sometimes the Printed labels on the tube might obscure it.
Finally, much patience is required when rolling tubes.
For these small preamp tubes, you require at least 50hrs of use before any definite tube rolling conclusions can be made.
Most famous NOS tubes might even sound downright awful if they have not been sufficiently burned in.
Have fun tuberolling !
It is an €£¥$$$$$ hobby.
As most headfiers put it, " welcome to Head Fi, sorry about your wallet!"