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Old 11th April 2006, 07:59 PM   #1
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Question Hytron big 71A

Hello Diy members,

I have bought a nice and strange pair of 71A tubes on Evilbay.
I made a picture of a normal nikkel plate 71A and the Hytron blackplate .Now I am looking for some data about this big Hytron.
They test on the weak site but the same on my 177 tester, so I think they are a bit different than the normel one because the tubes are N.O.S
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Old 11th April 2006, 08:15 PM   #2
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Looks more like a VT-52. Does it have any markings?
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Old 11th April 2006, 08:28 PM   #3
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Default Hytron 71A

Hello,

On the glass envelope is the orginal 71A mark ,on both tubes.

Thanks for your reply.

Martin.



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Old 11th April 2006, 11:04 PM   #4
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Fair enough! Never seen one like that before. Big brute for a 71A.
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Old 12th April 2006, 12:15 AM   #5
Rocky is offline Rocky  Norway
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Never seen a 71A like that before. Tell us what you find out, I use 71A and would be especially curious about those big bulbs of yours... Could it perhaps be they arent 71A at all, but simply have the wrong marking?? Never seen that happen before either, but they sure don't look like 71A.
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Old 12th April 2006, 02:03 PM   #6
jlsem is offline jlsem  United States
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If it's mismarked the filament voltage used to test is too low. I have seen tubes mismarked on the glass as well as the base, e.g. I had a 6A3 that had 5Z3 etched on the glass. It sure looks like a VT-52.

John
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Old 12th April 2006, 06:26 PM   #7
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Here are some more pictures of the Hytron tube.

Thanks for your reply.
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Old 12th April 2006, 06:29 PM   #8
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And another one,
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Old 12th April 2006, 06:31 PM   #9
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And another one
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Old 12th April 2006, 07:49 PM   #10
testlab is offline testlab  United States
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Datasheet here

http://frank.pocnet.net/sheets/021/7/71A.pdf
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