Hytron big 71A

[Diy martin]

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

 

[i_should_coco]

Looks more like a VT-52. Does it have any markings?

 

[Diy martin]

Hytron 71A

Hello,

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

Thanks for your reply.

Martin.



😀

 

[i_should_coco]

Fair enough! Never seen one like that before. 😕 Big brute for a 71A.

 

[Rocky]

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.

 

[jlsem]

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

 

[Diy martin]

Here are some more pictures of the Hytron tube.

Thanks for your reply.

 

[Diy martin]

And another one,

 

[Diy martin]

And another one

 

[testlab]

Datasheet here

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

 

[i_should_coco]

Here's a Hytron VT-52

 

[i_should_coco]

And another. Looks *very*similar.

Cheers,
Pete

 

[Diy martin]

Hello Pete,

I have found some pictures and data about the tube on
www.vt52.com
And I think that it is a VT52 and not a 71A , not a bad deal,
62 USD for a pair 😀

Thanks for your reply.

Martin.

 

[i_should_coco]

Hi Martin, They're nice tubes, I think you got a good deal 🙂

Have you tried testing it as a VT-52?

Cheers,
Pete