18Watt.com

I confess to not seeing any of these before, but a bit of searching seems they are rated.
I have bought a quantity of Yellow marked Tesla EL84 from a bulk trade pack of 100, they have been graded and matched already.
They have what I presume to be hex plates ?
Does any one have a link to decipher the codes ?
As an example one has ZZ on the lower body and 051 around the neck. Another has ZZ and 001 on the neck.
I haven't decided whether to sell these or use in my own amps yet.
Pictures below.
Steve UK
www.valvepower.co.uk

PP as in Pushmi-pullyu - I've never seen anything like it in my life!

What I can say -

I have some Tesla 12AX7 rocking horse droppings which have two-letter factory codes. These look like the standard RFT 12AX7 which are frequently seen marked "Tesla Made in Czechoslovakia" with 32 or 37 Prague codes, but they have the typical Tesla getter, rather than the RFT ring getter.
The two-letter codes were used in the Slovakian factories - VK is the current JJ factory, but there were others.,

My thoughts are that these were not made by Tesla, but Tesla labelled everything they sold as made in Czechoslovakia anyway. The getter is characteristic of Tungsram - the double ring is very Hungarian. I would say that they are "bought in" from Tungsram and labelled in Slovakia, rather than Czechia. Mind you, they don't look like typical Tungsram. I have seen Ukrainian produced 6p14p with the double ring getter, but they don't look like those, either.

They have what I presume to be hex plates ?

They don't look like it from the pictures. Those anodes look fairly cylindrical, without the angled.

Another has ZZ and 001 on the neck.

Should be great for ZZ Top tones!

Hex plates are hexagonal. Those could very well be tesla round plates which I think sound better. Regardless I don't have a pair to compare as my ex wife has my stash and won't let me at it. Try tube monger for pics

Like you said - they are not hex plates.
Like I said - those are not Tesla getters.

If I had to guess I'd say Lorentz, because I've never seen one and I know they exist - and very few people could argue, because they haven't seen one either. They're not a mainstream design, and they had a lot of variants - here's one with a double ring getter -
http://www.tube-classics.de/TC/Tubes/Si ... EL8414.htm
but a lot of others had a D getter, or 3 slots, or one big slot, or a "long" ring getter. And some other types were made for Lorentz by Tungsram, and some of those had a double ring getter. Jury's out ...

Tubemonger do nice pictures.

People who spent all their formative years in the US, after valve manufacture had ceased in most of the Western world, will not always be entirely accurate with their descriptions - especially when discussing things made in foreign parts from which they can make a profit.

I've had one of their people tell me I'm wrong on another forum, when the truth was that he was talking BS and standing on a heap of BS so he could talk down at me. 1000 posts to 3 - I can't be bothered to argue with people like that.

Tubemonger do nice pictures. They are human. Don't assume that their descriptions are entirely accurate. They didn't have a pic of anything like this when Steve made the original post, anyway.

I don't think these are Lorenz - here you can see some good pictures of Lorenz EL84 tubes:
http://www.jogis-roehrenbude.de/Roehren ... Lorenz.htm

I believe that the tubemonger info is correct - it seems that Tesla have used those getters only in 1963 (the date codes shows that too) so these tubes are rare:
http://www.tubemongerlib.com/gallery2/v ... a.jpg.html

Peter

Even rarer now all 100 in the 'bulk trade pack' are now sold.
Steve UK