One for the valve experts!

[Norman Raeburn]

Hi Folks, I am looking for some help/information. I have a pair of Edicron nos valves which I will be selling soon. Can anyone identify who made them and when. I did a bit of searching and they might be Philips made in the Netherlands. Can anyone confirm please. The batch numbers are K9JH9 and etched on the glass is KM4 with what I think is ASH underneath. Many thanks, Norman

[joebog1]

I have a quad of very similar description. Without stealing your thread, I am also very interested to see what people say. I bought these as a matched quad about 30 years ago. The production numbers match, but as to wheather they ARE matched I have never checked. The reason I havent used them is the colour of the gettering in the top. I am more used to seeing silver rather than black.

Joe

[Maarten]

If it says A5H, with an A not another triangle or such character, on the second line, they were made by Philips Austria which is plausible for EL84 in that era.

It should say kM4, not KM4, on the first line.

5H on the second line suggests august of 1955 or 1965. Revision 4 on the first line suggests it should be august 1965.

P.S. The ink they used for the factory codes is a bit more sturdy than the chalk used for the normal branding and typing, but it can be wiped off, so don't try to clean up around it thinking it's etched and won't be wiped off.

[Diabolical Artificer]

No idea what they are Norman, other identifiers are anode shape/length, mica former shape, getter shape, does the glass envelope have a seam on top and is there a stippling on the bottom near the pins?

There's a load of pics here Norman - http://www.tube-classics.de/TC/Tubes...0EL84/EL84.htm and of coarse there's the valve museum. One other code ID sourec I found - https://www.vivatubes.com/identifyin...-and-eia-code/ good luck, Andy.

Edit more code info - https://www.effectrode.com/news/tube...st-tube-codes/

[Robert Gribnau]

Like Maarten already wrote, the tubes seem to be produced by a member of the Philips Group. Attached is the document "Philips Factory Valve Codes" from 2011 (which as far as I know is the most recent version).

[snowman_al]

Umm,
They look very much like Ei valves.
They were made by the Ei factory in Nis (was in Yugoslavia). They used a mix of Philips and Telefunken tooling. They also used a similar 'etch code' system, with KM4 being one for EL84s.
Their factory symbol was a horse shoe with a dot in the centre. See thumbnail. Perhaps it looks like an A?

You can find them branded as Ei, Edicron, even Siemens, plus others.

[Norman Raeburn]

Many thanks for the replies and suggestions. I have had another look at the codes through various magnifiers and I can confirm the first line is kM4. The second line as snowman_al suggests is a horseshoe with a dot in it and a 5 or S then H. I don't know where I am now, this is so confusing. Norman

[snowman_al]

It confirms they are Ei production. They are excellent valves.
They could date from 1980s to 2010s. I'm not sure if the Nis dating system works or is even recorded. (Maybe someone knows when Edicron started?)
Ei were one of the largest valve makers long after Philips et al. left the trade. Unfortunately they ceased production in 2014 due to conflicts and under funding.

Some of the original Nis machinery has ended up with the BRIMAR / Great British Valve Project https://brimaruk.com/menugbvp/great-...lve-project-2/ so may be used again?

[G6Tanuki]

Another thing that would confirm that they are Ei manufactured is that Ei valves usually have rather sharp tips to the pins - much more pointy than the likes of Mullard or Philips.

[snowman_al]

Care there,
Some of the Edicron EL84s attributed to the Nis factory in previous threads were actually Russian made, which do have very pointy pins. (The micas and getters are different too.)

If you look carefully at Norman's picture you can see a ring getter and 'star' micas, little ears that touch the glass and rounded pins.
If you look at Joebog's picture those have saucer shaped getter pans and micas without the 'ears' and pointy pins. Those are Russian made (6P14p) valves branded Edicron.

[Norman Raeburn]

Hi Folks, I can confirm the pins aren't pointy.

[joebog1]

Pins on mine look like they have been "sharpened " with an angle similar to a pencil sharpener.
Read: VERY sharp.
Now I know why I have never used them. They looked russian to me, and were priced similarly.
Black gettering??, anybody have thoughts on this ?. To me it looks like they have already done 20,000 hours with the black rather than silver.

Joe

[Diabolical Artificer]

Looks like a positive ID, if you sell em on Ebay Norman, sell em separate unless they're matched.

Don't know why you dislike Russian valves Joe, in my experience they're absolutely fine. It's a bit like saying all German Shepards are no good cos one widdled in your slippers in 1994. Some may be iffy but not all. Some 6H8C's I have, have no gettering, they work fine,unless they're brown they should be fine.

Andy.

[joebog1]

I have been burnt so many times Andy, with ruskie valves. Every time it cost me money either under warranty, or to replace noisy, hummy, distorty valves. I am VERY wary of them indeed.
I had that quad for 30 years and every time I look at them I think, Nah!! look like junk.

Joe

[Maarten]

If they have the dotted horseshoe, they're definitely made by Ei, not in Russia.

I think the date codes followed the same system as the 1950's/1960's Philips codes, and revision 4 is probably still plausible for 1975, but 1965 production is probably also possible.