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Can anyone please help me identify a pair of NOS Siemens tubes with the lettering almost vanished?
I bought them as E88CC (6922) tubes, but they are different to the other NOS Siemens E88CC tubes I have.It is possible to read the letters «E8....» on one of the tubes. Inside, the metal is stramped «A6» and «7F» on both tubes. To me they look similar to other Siemens E88CC tubes, except for one thing: They only have a thin rod with a circle on top above the main (gray) section, while the others also have a narrow piece of flat metal bent somewhat like an «A» between the main section and the top ring.
The tubes that I know are E88CC, have codes like this:
«A4/9F», «A4/8G» and «A3/8A»
I am afraid to use these tube in my preamp before I get to know what the really are. Please help!!!erlandsen
Follow Ups:
These codes are a mystery to me, too. Perhaps your post will lead to a response from someone out there who knows this subject. But in the category of here's what I know:Late 50's and early 60's Siemens tubes have etched codes toward the bottom of the tube, in 3 rows, running parallel to the pins. In the top row I have seen a letter followed by an "O" with a "/" through it. (I don't know what this letter or symbol means.) In the second row there is a number and a factory code. (An "=" symbol with a "|" through it denotes the Siemens, Munich factory.) And in the 3rd row there is a number and a letter. These early tubes have a halo getter inside the top of the tube and the halo is supported by a bar rising from the splatter shield.
As I understand it, at some point, by the mid-60's at least, the etched coding stops and codes began to appear on a metal tab running from the upper mica. Perhaps someone can tell us how to read thes codes. The getter structure is the same as stayed the earlier tubes, with a halo-shaped getter supported by a bar.
In the early '70's the getter structure changed to the "A-frame," with a halo supported by 2 bars in the shape of an "A". These tubes also have a tab inside with codes.
Then in the late '70's and continuing into the '80's, the getter structure changed to what I think you describe, with a shinier halo loop supported by a single wire (and no splatter shield). These latter tubes also have the metal tab with codes. They are also usually the least favored sonically (but YMMV). And in my experience I prefer the earlier one-bar tubes to the A-frame type.
That is my .02, all based on my own observations and what I've been able to pick up here and there. The factory codes are taken from the list which also includes the familiar Philips/Amperex codes.
Others with more or better information, please help.
With the popularity of some Siemens tubes the code should be easily explained, but in the years I've used them could never find a description anyplace for what each part of the code means. Some have the stamped type you describe and the E83CC have two lines of three character codes etched in the glass.The thin wire support you describe is the latest E88CC from Siemens (I think late 70s / early 80s) so that part is legit. If the rest of the code or printing is convincing then they'll probably not do any harm. Fran
"The truth is out there"
They are later versions. Most of them sound a little bit brighter than the older one. You can use them without any troubles. In my opinion one of the best made 6922 for ever.
Thanks a lot!I have tried to post pictures, but I can't figure out how.
What is the meaning of the codes I refer to? Is it a system like the Philips/Mullard coding, where you can tell the place and time of production, along with the tube type?
sorry I quite don't understand what your problem is, but it is ABC to me!!
sorry, no means to offence , just try to put up an example.
Did not mean to create fuss either. Take care!
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