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calling all 6sn7 geeks! prove your tube knowledge superiority


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Hi trainspotters  ermmm tubespotters!!

I seriously doubt I have discovered anything new but I am not familiar with this tube contruction and cant find a reference to it anywhere. FInally those of you  that have spent too many hours looking at 6sn7 tube types (like me) have hit the jackpot!  Time to show your tube knowledge superiority. 


TO make this a bit fun please dont post your answer below but send me a pm, You can post things like Answer sent!! or Dead easy or whatever to inspire some competivive spirit with your fellow tube geeks and hopefully reign supreme tubespotter.


It is labelled as a Mullard 6sn7gt made in Britain.






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@audiofeline an excellent start to the proceedings, this is the tube you chose.


NOSBritish6Sn7GTCV1988-1__509671.jpg but unfortunately although the tube you chose has curved plates and grey glass the plates in the "mullard" are round much like  a tung sol round plate , however the plate has a seam on both sides

this is a pic of a tung sol round plate 6sn7 

6SN7 5692 CV1988 VT-231 | tubemongerlib


Excellent work though, thanks for trying. You are welcome to have another go


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10 minutes ago, xlr8or said:

At your service. ?

Mr xlr8or, I am starting to realise that my intial post may not be as clear as I thought. I have the above mullard in my collection but I havent been able to find another like it mentioned anywhere. Whille there are mullard 6sn7gt's they dont seem to be the same as this one. 


Taking photos of grey glass tube insides is hard so will explain the structure - tall bottle, grey glass round plates with seams on both sides and a top d getter.  If you know where I can find this tube referenced on the web or any other pertinent info please pm me.

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I'm often referenced on a lot of sites for valve identification and am happy to help out. I also have a fulltime job over at AA under tubes getting PMed a lot to help out in the background to identify codes/manufacturer.


When taking photos showing the internal structure behind the grey or black smoked glass envelope, it often helps to have a very strong light shining from behind. Day photos are the best that look up directly to the sun. Hold it up like a biblical object and use it like a lens and rotate it to examine the internal structure.


Will message you to confirm manufacturer.

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The OP's valve is challenging to identify because of its unique structure; it has round anode plates and D getters on the top mica plate.


It's not a Mullard or Tungsram Tottenham 6SN7GT or a Philips Adzam Brussels 6SN7GT from the mid to late 1950's as the internal structure differs. It's also not a black phenolic base Osram/Marconi/GEC B65 or Brimar 6SN7GT CV1988 valve. It doesn't look close to any Mullaed ECC33 valve. It doesn't have any etched codes on the glass envelope or any white printed codes at the bottom between the 8 pins and key pin. It is also missing the BVA elipitical shaped symbol. It looks damn close to a US manufactured valve from RCA, Tung-Sol or Sylvania. We'll find out what it is but it will take some time to confirm.


A good site to reference photos is below.




Here is a similar pair but with the BVA symbol:




Here are other lookalikes:






Edited by xlr8or
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