2A3 identification

[Alberto86]

hi all,

Someone offered me a pair of 2A3 NOS.
I’ll have him tasting the tubes in front of on but anyway he told me they are nos readings.
One of the tube is branded Raytheon and the other National Union. The seller says they are in fact the same tube and both made from Raytheon.
A part of an ‘’A’’ on the bottom of the National Unions there are no other codes readable on the tubes.

Attached the pictures of the tubes.

My 2 questions:
- is it possible that they are the same manufacturing company? If yes what years of production are we talking about? 40s, 50s, 60s?
- any of you have experience with Raytheon 2A3? Are they supposed to be good nos tubes?

Thank you in advance for all the help you can give.

Best

AB

 

[Alberto86]

PS: they are both black bi plates with spring type supports. In fact they do look identical.

Thanks again for any input.

 

[Palustris]

It is very possible they were both made by NU, but the photos need to be larger and clearer to determine if the tubes are the same manufacture. In particular, look at the top wafer looking directly down to see if they are the same construction e.g., have the same number and shape of holes in the same locations.

 

[Alberto86]

Hi Palustris

Thanks for the info.
I attached all the pics I have.

Any guess?

Best

AB

 

[mhardy6647]

see
http://emissionlab.net/2A3.html

PS bigger photos next time, please!
I don't recognize them -- the filaments are like some RCAs, but the mica insulator/spacer isn't.

AK resizes photos uploaded here-- but clicking on them brings 'em back.

 

[Alberto86]

Hi Mhardy!
Thanks for the tip.

I check out your link. They look like Sylvania. http://emissionlab.net/2A3/SYL2A3.jpg
Is that possible?
If they are they should be great tubes.
By the way I tested them and on TV-7 they test 81 both (38 being the minimum)
I attached the top view in bigger format.

Any comment?

 

[mhardy6647]

Yeah, they do, don't they?

 

[Palustris]

I happen to have three NU 2A3s and one Raytheon 2A3 and the wafer on all four tubes matches the Zenith, Canadian Marconi, and GE photos in the 2A3 world link. In the end, it doesn't really matter who made the tube, it is more important to get matched tubes. They all sound great.

 

[eickmewg]

Check the EIA codes for manufacturer, Check this out http://audiokarma.org/forums/index.php?threads/eia-codes-learn-to-love-them.497168/