Mystery Tubes - EL84s and 12AX7s Old-Stock

[Shottky]

I have two sets of EL84s that are unidentified and one set of 12AX7s that are also unidentified. I got all the tubes from two separate Hammond Organ purchases.

Originally I wasn't going to ask what the tubes were. I plugged the Realistic EL84s (from organ #2) into my amp (pre-zener mod) and they sounded awful. I used two zeners to drop the B+ 20 volts. Anyways, today I decided to try plugging in the Realistic tubes again... and they sounded wonderful!

So now I'm trying to figure out what they could be. I've also decided to ID the other two sets of tubes that came with organ #1.

I've included some pictures.


Lowry EL84s.
-One tube says "Made in Holland" (Amperex? tubes?)
- The tubes have little foil-looking aerials bellow the halo getter.
- At the bottom of the both tubes the following is barely visible
- Sounds excellent... for what it's worth.

Stuff in brackets is a description.
?X? (smudged out where ? given)
(Triangle)3C1



Realistic EL84s
- Nothing except the big printed logo and 6BQ5/EL84
- Gold pins?


12AX7s
Tube 1:
- ARBL in grey etching at top
S28?? (smudged out)
63-21
in yellow besides lowry logo (which is smudged)
- "17' etched in the bottom glass


Tube2:
AQBL in grey at top
S2806
63-21
in yellow besides Lowry logo
MADE IN _____ (smudged out on side)
- "11" etched in the bottom glass

[dotfret]

Firstly, Realistic valves are a "trade secret". They are always 10M spec, low noise and long life, top quality. Because they are always rebranded, people do not know what to expect, and avoid them because they are often MIJ.

The EL84 marked Made In Holland has a Philips code on it. Not very distinct, but I can see it in the pic, near the base. So it is probably made in the Philips Eindhoven plant in the 60s. Later Philips group EL84 (69 onwards) are 6BQ5 pattern, which have round holes instead of the slits (and don't sound as good in guitar amps).

The other EL84 are the same Philips pattern. If you can find codes on them, like on the MIH valve, you can get more info. If they have no codes, it is likely they are MIJ by Toshiba.

The 12AX7 look like standard USA manufacture, to the US version of the Philips I6 design (short plate). I would guess that the one with no other marks is an RCA. The etched mark on the other one suggests Sylvania or GE (but not Kentucky manufacture).

Realistic valves were always "bought-in", but they were always top quality whatever the source (and that was often Mullard or RCA). Better than a lot of "run of the mill" stuff, but often ignored - through ignorance.

[Shottky]

No additional codes on the Realistic valves - I did a thorough check.

I should specify that both 12AX7s have etch marks, just in the picture the other one is turned away from the camera.

Thanks for the input!

[dotfret]

If you can decipher the Philips code a bit better, you might get to know more. Should be 3 characters over 4 characters, but it looks "frayed". All the same, sometimes you can see the shadow of the mark on the valve's internals, even if you can't read it directly. And sometimes, if you do it carefully, you can chill the valves in a refrigerator, and then see marks as condensation forms on them when you take them out - you have to watch like Hawkeye, because you can easily miss the point when the codes become visible.
The factory mark for Eindhoven is the right angled triangle - 1st symbol, bottom line.
And to be correct, those marks are not "etched". I know that's what everybody calls them, but the truth is they are "inked on" marks that were transformed to what you see by the heat used during manufacture. Cobalt in the ink gives that result.

[dotfret]

Call me a sinner - the page did not load properly when I first looked at it.
Now, re. those 12AX7s -

I realised that the S280 is actually the US manufacturer code for Raytheon. That does not indicate the manufacture source, but the US supplier. 63-21 is a date code, week 21 of 1963

As far as I know, Raytheon stopped their US manufacture around 1961, but I may be wrong. They were still operating plants in UK (STC and Brimar), but they did not use "etched" codes like that in UK, in my knowledge.

I do have some ca.1970 MIJ Raytheon 12AX7, but they do not have the etched codes, either - and the getters don't look "right". Also, most of the mainline 12AX7 manufacture have another (semi)circular hole in the plate side. No side hole indicates a US design.

Raytheon is my best guess.

[Alexo]

Look very closely at the base of the Realistic EL84's - inside the ring of pins, looking at it from the bottom, is there a little diamond stamped into the glass?

[dotfret]

Good point, Alexo - they might be Telefunken, and the diamond is unmistakable.

But it occurred to me that there was another plant which was sloppy abput putting the Philips code on - the US Amperex factory. Unlike other Philips plants, who put the code near the base, Amperex would often put the code on the shoulder, or halfway up the valve, so that it got obscured by the screenprinted logo. Try looking through from the back to see if the code is under the yellow stuff. The factory code is an asterisk * for US Amperex.

[Shottky]

After wiping the grim off the top of the Realistic tubes, I noticed that it has a double-seam. There is what I would call a minor seam, faintly visible, perpendicularly intersected at the tip by the major seam, which is much more visible. I haven't seen that before on an EL84, but then again I only have six in total.

No diamond. Just a plain glass base, relative unremarkable except that the interior circle of one of the bases is more opaque than the other. I could take a picture of it, but I don't think it corresponds to anything other than a different glass plate for the bottom.

No codes either, on the realistic. It's bright and sunny right now, so all the minute features are easily visible. I can't spot a single code anywhere, other than the yellow EL88/6BQ5.


So the Lowry 12ax7s may very well be supplied by Raytheon? I suppose the question would then be, did they make them themselves or purchase an order to resell with their brand-name?

[dotfret]

I don't really know enough about US valves to say much more, but I'm trying to give you all that I have.
What I can say is that valves marked like that usually sound a lot better than the standard NOS stuff.

US "manufacturer codes" indicate the "responsible supplier". As an extreme example, I have seen RCA branded 12AX7 with the RCA manufacturer code, and a Mullard Blackburn factory code!
There are lots of possibilities. You have to remember that STC was its own biggest customer, so Raytheon (and Heintz & Kaufmann) were really big wholesale suppliers, but the STC communications operation was where they made most of their sales.
STC had valve factories all over the world but, because they were mostly using their own products, you don't see a lot of Raytheon in the marketplace.

I have seen similar style "etched" printing on (mostly) GE and a couple of Sylvania branded valves, which were not the standard GE design. I have also seen Raytheon valves branded as GE, which are easy to spot because they have the code "etched" on like these:

http://www.tubemongerlib.com/gallery2/v ... A.jpg.html

[zaphod_phil]

As far as I know, Raytheon stopped their US manufacture around 1961, but I may be wrong. They were still operating plants in UK (STC and Brimar), but they did not use "etched" codes like that in UK, in my knowledge.

What was the connection between Raytheon, STC and Brimar? Was it common ownership? Was Brimar just a relabler? I have a Brimar 12AX7 which is absolutely *identical* to a Mullard "ladderplate" ECC83 I have, except it doesn't have any Phillips/Mullard production code marked on it. I also have a pair of identical 6V6s - one is "Foreign Made" Brimar and the other is a Russian 6Pi6. The only difference between them is the markings. So did Brimar make anything of their own?

[dotfret]

STC were, and are, a worldwide telecomms company. Many companies worldwide were part of their group at one time or another. They were the owners of Brimar and Raytheon.

STC do not market themselves to the public, most of the companies they own sell services to industry. A key factor of their marketing strategy is that they are "vertically integrated" - you get good service, and their products are not available elsewhere.

STC still own the Raytheon brand name. I am not sure what they are using it for these days, but about 25 years ago they used it for marketing word processors and computers, which were marketed to industry, not the general public. They were still producing some Raytheon valves in the far east in the 90s - I have seen a few.

Regarding Brimar: There were manufacturing plants in Rochester, Kent, and Hampshire, and a small separate STC facility near Orpington which was mainly used to provide valves for military purposes.

When EMI launched their campaign in the 60s to buy up the British valve factories, STC were quick to sell out Brimar to EMI. Since they already owned the Mullard factories, and demand for valves was falling, Thorn-EMI firstly closed the Kent operations, and concentrated the manufacturing effort into the Hampshire plant. When demand for products fell further, the Hants operation was closed.

Brimar licensed the short plate ECC83 design from Philips, as did most of the world's manufacturers. Even RCA, the inventors of the 12AX7, used that same design, although I am not sure that the design was exclusively Philips group - the short plate might have been a collaborative Philips/RCA effort
There are similar valves from eastern bloc manufacturers, like RFT and Tungsram (something tells me those people did not pay royalties).

Brimar coded their valves very badly - if you are lucky, you find a silk-screened line of small print on a valve, which is their code, but mostly it is rubbed off or was badly printed in the first place. If a Brimar valve has a line of faint "etched" print along the axis of the envelope, then it is Ediswan production labelled as Brimar. Those two companies used to relabel each other's production very frequently, so, whether it says Mazda or Brimar, you need to look for that line of print to tell one from the other. If there is no code, or a silkscreened code running around the valve, it is probably Brimar manufacture, if there is a code along the tube, it is probably Mazda Ediswan.

Brimar bought in some Russian valves to cover production gaps after the Kent operations were closed down. If you look at your Brimar 6V6, it probably carries a Russian date code for '68 - like the pair of Brimar 6L6G I have in my shed, which are also marked 6pi3s and probably made by Svetlana.
Just about every manufacturer bought in valves from time to time, even Mullard. The obvious example is the ECC804 - Ediswan made those, whether they were marked Mullard, Philips, Brimar or Mazda. If you get a Mullard/Philips version, it has a [ laid sideways next to the logo to indicate External Supply. And that long code along the envelope. Most of the valves that Mullard used to buy in were TV types, so you do not see that External Supply mark much on valves that are currently traded.

I should have mentioned that the few Japanese Raytheon 12AX7 I have seen have very distinctive getters - a ring getter directly attached to the top, without a support post, at an angle of about 40 degrees - so if the valves in question were MIJ, they are not like other MIJ Raytheon I know about.

[clobo]

Hi,

This is a very interesting discussion on ECC83/12AX7 short plate collaborative (?) design (RCA v/s Philips). Thanks.

I happen to own a lot of Japaneese models, and also some originals. BTW most of my Japaneese are rebranded (namely Raytheon, CGE, JRC, Westinghouse...). All share that same short gray ladder plate pattern.

To my ear, different plate holes patterns (or absence of) and various getter styles and mountings, all sound the same. However I do hear that typical US v/s UK tone seems to resides in pin-to-plate aligment.

For example, the 2 pictures seen in the original post have that typical US style pin-to-plate aligment (pins 123, and 678, are parallel to their respective plate). To my ear all my tubes sharing this aligment have a more articulate Fenderish tone (RCA style ?).

The rest of my tubes have their pins actually rotated approx 90 degree (Philips style ?). To my ear they all sound more creamy in a Marshall way.

Others might may hear something else, this is what keeps tubes so captivating

Claude

[Shottky]

For what it's worth, I put one of the 12AX7s in the V1 position and put the Realistic EL84s in the output. Sounds amazing. This is quite possibly the best my amp has ever sounded. I'm going to stick with it for a few weeks to get used to the tone, then I'll put the Holland-EL84s in.

Thanks for all the input, I've learned a lot about tubes in this thread.

[TimbreWolf]

I realised that the S280 is actually the US manufacturer code for Raytheon. That does not indicate the manufacture source, but the US supplier. 63-21 is a date code, week 21 of 1963

As far as I know, Raytheon stopped their US manufacture around 1961, but I may be wrong.

Bingo! - at least for the Raytheon EIA code of 280. Raytheon outsourced to Japan, beginning in '62, and those are Japanese-made 12AX7. From the looks of them, I'd say they're made in the Toshiba plant (for Raytheon).

The EL84 marked Made In Holland has a Philips code on it. Not very distinct, but I can see it in the pic, near the base. So it is probably made in the Philips Eindhoven plant in the 60s.

Oh, so close... The slanted triangle/delta indicates the Heerlen Philips plant. Eindhoven would be a "T" symbol at the beginning of the bottom line of code. I've never seen Eindhoven-made EL84, but have seen Heerlen (such as that one) and Sittard ("X" code, my favorite EL84), from Netherlands.

A little correction about the plate "hole" - a single, round hole in the plates is indicative of Mullard's Blackburn production. Two plate holes, with lots of silvery getter-like deposit, on the sides of the glass, would indicate Tungsram production (so would a little square metal tab with number on it, inside, on the getter support wire).

Those etch codes are essential for proper i.d. Check out this resource for more information.

Shottky - for better success searching for more of such organ tubes, make sure you spell the organ company as "Lowrey" instead of "Lowry."

Cheers!

- Thom

[Shottky]

Thanks for the input TimberWolf! And duly noted about the Lowrey correction!

[dotfret]

Heerlen, definitely - a clear demonstration that I tend to post while drunk - I usually end up apologising afterwards. Sorry.

A lot of the info is unclear, but there's a couple of things I can say.

As Clobo pointed out, those 12AX7 have an American look - not just the base pin alignment (which is something I have learned from this discussion, thanks) but the absence of side holes in the plates is a US characteristic, too.

The Toshiba plant was set up in collaboration with Philips, and Toshiba 12AX7 are usually ECC83 pattern - so I don't think Toshiba is the answer. Panasonic would be more likely, but I would expect an RCA style "stop sign type box" on anything they made.

I have seen that style of etched coding somewhere before - I just don't remember where. To quote Tom Paxton, "Could've been the whisky, might've been the gin ..."

I've put up my list of EIA codes on www.wy9.co.uk - it is not particularly special, but there are one or two on there that are not in the other lists already on the web.

The best general resource for Philips codes is, unsurprisingly, on "Frank Philip's" site. Go to http://www.mif.pg.gda.pl/homepages/fran ... index.html

and download Alan Blake's Philips Code List.
The 1964 list was a "snapshot" - it is the only original document we have, but it is evident that, at times, obsolete codes were re-used, new ones were introduced after 1964, and some codes which were used briefly were not included - r9, for example, is not in the original list, but I've seen it on a lot of Mullard Mitcham ECC83 longplates from around 1962.
The Alan Blake version is being updated by including information found from codes on valves.

[TimbreWolf]

I've seen it on a lot of Mullard Mitcham ECC83 longplates from around 1962.

Uhhhmm... yeah! Mitcham didn't make ECC83, and Mullard discontinued long-plate construction in their ECC83 in 1959. Those were produced in their Blackburn facility.

Couple of other things: Panasonic = Matsush*ta. And "pin alignment"?? "Toshiba 12AX7 are usually ECC83 pattern"?? What's this about, now? I'm new around here, so I guess I have to learn the language.

"Could've been the whisky, might've been the gin ..."

Ohhh!! Okay

[dotfret]

Uhhhmm... yeah! Mitcham didn't make ECC83, and Mullard discontinued long-plate construction in their ECC83 in 1959. Those were produced in their Blackburn facility.

So you believe that? I'm not going to argue ... I sold the evidence a long time ago. But I can tell an R from a B, and I'm not talking about a smudged code on a single valve. I bought a couple of dozen, type coded r9, date codes around 61-62, pulled from old equipment, from a man at a car boot sale about 4 years ago, and sold them on eBay. Anyway, all the Blackburn longplates I've ever seen had mC codes.

For years I believed that the E80F was only produced by the Philips Heerlen plant. All the ones I have are made in Holland, whatever name is on the label (Mullard, Philips, Telefunken etc). Then I saw a few on the net, that were made by Valvo - so many that I now believe Valvo made E80F as well.

Now, last week I saw this E80F made in Mitcham -
http://cgi.ebay.co.uk/E80F-6084-Philips ... .m63.l1177

I think Uncle Ned can be trusted to read a code, so I believe him, although I never saw the like before.

And somewhere I have a Realistic 12AZ7A with a Blackburn code. C'mon, tell me it is a myth!

ECC83 pattern?
Turn your 12AX7 so that the gap between pins 1 and 9 is facing you. If you are looking through the gap between the two triodes, it is likely that is a US design. If you are looking at the face of a plate, it is likely that is a European ECC83 design.

I like to learn ... someone on here helped me to that easy diagnostic test last week - thanks, Clobo. I've been using other ways of describing the difference for years, like most US designs do not have ventilation holes in the plate sides ...

[TimbreWolf]

I bought a couple of dozen, type coded r9, date codes around 61-62, pulled from old equipment, from a man at a car boot sale about 4 years ago, and sold them on eBay. Anyway, all the Blackburn longplates I've ever seen had mC codes.

Aha! The mC1 long-plates were earliest (square-getter), but then the halo-getter f91 and f92 long-plate ECC83 versions were made, in '58/'59. I have seen many of these where the type code (f9_) is only partially applied, which is where you may be interpreting as "r9" types. Mullard discontinued production of long-plates in '59, or perhaps earliest 1960 at the latest.

Mitcham seemed to dominate the ECC81 production, though I do have a '50s Blackburn ECC81. But I have never seen, nor heard of a Mitcham-made ECC83 - and I've been paying attention for quite some time. I'd like to see a photo, if you've got one.

And somewhere I have a Realistic 12AZ7A with a Blackburn code. C'mon, tell me it is a myth!

?? "Realistic"-tubes are all re-labels. Many "12AZ7"-labeled tubes are really relabeled 12AT7. Want to discuss "National" tubes? I even consider "Amperex" to be a re-label, since it was so liberally applied. Seriously - I've seen that little bugle boy logo painted on British (Mullard), German (Valvo and Siemens), Belgian (Brussels "Adzam" facility), Swiss (Vienna facility), Heerlen and Sittard Philips, even Yugoslavia's Ei and Japanese-made tubes; he really got around!

ECC83 pattern?
Turn your 12AX7 so that the gap between pins 1 and 9 is facing you. If you are looking through the gap between the two triodes, it is likely that is a US design. If you are looking at the face of a plate, it is likely that is a European ECC83 design.

That's an interesting distinction. One which I've never taken advantage of. I'll have to check it out - thanks!

most US designs do not have ventilation holes in the plate sides ...

It helps to pay attention to details like that. However, there always seem to be exceptions... such as the long-plate GE 12AX7.

Thanks for your reply.

- Thom

[dotfret]

The longplate GE 12AX7 ? Silly boy - that's a B339 ! Now just rub that flaky stuff off and get the silkscreen machine out ...