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Old 23rd February 2013, 03:53 PM   #11
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Lettering looks genuine upon further inspection the inside looks nothing like any of my german or usa made tubes. It does infact look like a chinese tube I once saw... Who has the time to strip and repaint cheap tubes? Or did they make them that way? I would say that it is probably worth about ten bucks if it works and someone with ten bucks needs it.
Also there are lots of websites dedicated to preamp tube identification. Apparently the lettering on the outside is not nearly as telling as the structure inside. When you get a good collection going you will be able to Id tubes without any paint at all. I did not look closely at the pic the first time I'm eating my words...
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Old 23rd February 2013, 05:06 PM   #12
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It is correct, these are fakes.
I know most of the german small signal triodes - none look like this

Quote:
Originally Posted by v4lve lover View Post
here's a nice rule of thumb, if the inside connections are copper, its made by communists
correct !

Here are a few other communist-tube characteristics:
  • shiny, smaller nickel pins with sharp ends (except german democratic republic(GDR), those aren't shiny but sharp and pointed (WF, RFT, Funkwerk Erfurt))
  • the glass nipple on top is small, sharp and more fragile (except GDR)
  • the micas aren't shaped as usual like a star but more like a 4-edged-trochoid (except GDR and Hungary (Tungsram))
  • the system which holds the getter is not shaped as a circle or a "D", but more like a dish or pan.
  • From time to time you can hear "здоро́вье!" in your speakers


Quote:
Originally Posted by DF96 View Post
Interesting. I have not thought of that before. Did they have better accesss to copper than the nickel alloys used in the West?
No, just different technology. Soviets were particularly good in terms of metallurgy. Glass-metal-bonds/seals are a rather complex issue and different countries have developed different technologies.
Western countries use(d) a molybdenium-nickel-alloy whereas the soviets use(d) copper with a layer of copper(I)-oxide. The copper oxide is the link between the ion-binding in the glass matrix and the binding with metallic copper. Remember, copper(I)-oxide is semiconductor ! (direct bandgab - 2ev) [wrote ma last solid-state-physics exam today ] So the binding to the metallic copper isn't weak as with other oxides. So the color is not due to copper, but because of the even more red colored CU2O
Early rectifiers were built with this Cu2O: Metal rectifier - Wikipedia, the free encyclopedia

Some facts on glass-metal-seals are here: Glass-to-metal seal - Wikipedia, the free encyclopedia

A bit more advanced: http://downloads.hindawi.com/journal...975/509270.pdf

Hope that cleared things up a bit.
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Last edited by the_manta; 23rd February 2013 at 05:14 PM.
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Old 23rd February 2013, 07:45 PM   #13
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Quote:
Originally Posted by the_manta View Post


No, just different technology. Soviets were particularly good in terms of metallurgy. Glass-metal-bonds/seals are a rather complex issue and different countries have developed different technologies.
Western countries use(d) a molybdenium-nickel-alloy whereas the soviets use(d) copper with a layer of copper(I)-oxide. The copper oxide is the link between the ion-binding in the glass matrix and the binding with metallic copper. Remember, copper(I)-oxide is semiconductor ! (direct bandgab - 2ev) [wrote ma last solid-state-physics exam today ] So the binding to the metallic copper isn't weak as with other oxides. So the color is not due to copper, but because of the even more red colored CU2O

Hope that cleared things up a bit.
the russians likely used a full lenght of dumet wire for the seals and connections. as the welds to the thicker tube pins and the molybdenum-nickel. this increases the number of welds. they likely encountered problems whit welding the Three metals successfully.

in any case, its a stroke of genius. only using two sorts of metals simplifies production.

v4lve.
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Old 23rd February 2013, 08:25 PM   #14
DF96 is offline DF96  England
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Yes, shiny pointy pins with bright red seals are a dead giveaway for a 'Russian' valve. East German RFT and Hungarian Tungsram look more like Western valves.
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Old 11th March 2013, 07:18 PM   #15
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Sorry for not responding sooner. As a first time poster I was told that my post was going to be moderated before going live. I never received confirmation that it went live. I really appreciate everyone's input. Much to my chagrin, I have learned a ton!
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