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Paging Jeff West: Mullard Tube Question??

Jeff West

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The reply I tried to send before the above one is still held up, I guess, probably by a stock photo of black Brimar 6V6Gs with GEC decals.

But here's what I wrote:

" Nice photos, Paul. Yes, the mini KT66, I have some just like that. I agree that the details on top are a key identifier- are you satisfied they're a match to Oatie's?

Since we've come this far, though, here's the rub about identifying the actual maker: the GEC decal is a commercial label that is not part of the gov't/mil standards marking. It could be (and was) applied by M-OV to valves sourced from other factories, valves that may have been marked re: other standards, etc. That is, the GEC decal is not specific to a factory of origin in the way that, say, a "KB/Z" coding is specific to Hammersmith/M-OV.

So, for example, I have numerous 6V6Gs that have that have virtually identical GEC decals, also R.A.F. related "10E" codes, but were clearly made by Brimar, and have Brimar S.T.C.F. markings on the base.

Here's a stock photo of a couple, although unfortunately without any other markings showing, maybe I can get some more photos up later:

****

So, one question is, did GEC/M-OV really make the GECs in the last photos (***Pauls)? I believe I've seen versions of those with reliable "T' factory codes, but now it's on me to come up with proof! "


Another question relevant to this thread is: which of all these fine valves, if any, actually match up on physical characteristics?

Regarding the seemingly compromised Tungsram circle logos, those tubes were advertised as Mullards, make of that what you will.
 
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Jeff West

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877
" Beautiful quad of GEC military. "

See, that's the thing . . . they all have T codes specifying made by British Tungsram.
 

Jeff West

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iqavnlimoz6vcixbbse9.jpg


Above Brimar made, for certain.
 

ourmaninthenorth

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The reply I tried to send before the above one is still held up, I guess, probably by a stock photo of black Brimar 6V6Gs with GEC decals.

But here's what I wrote:

" Nice photos, Paul. Yes, the mini KT66, I have some just like that. I agree that the details on top are a key identifier- are you satisfied they're a match to Oatie's?

I think they bear more resemblance to the Mazda with the U shaped grid radiator that you posted.

Since we've come this far, though, here's the rub about identifying the actual maker: the GEC decal is a commercial label that is not part of the gov't/mil standards marking. It could be (and was) applied by M-OV to valves sourced from other factories, valves that may have been marked re: other standards, etc. That is, the GEC decal is not specific to a factory of origin in the way that, say, a "KB/Z" coding is specific to Hammersmith/M-OV.

So, for example, I have numerous 6V6Gs that have that have virtually identical GEC decals, also R.A.F. related "10E" codes, but were clearly made by Brimar, and have Brimar S.T.C.F. markings on the base.

Hear you loud and clear. Particularly well stated that Jeff.

Here's a stock photo of a couple, although unfortunately without any other markings showing, maybe I can get some more photos up later:

****

So, one question is, did GEC/M-OV really make the GECs in the last photos (***Pauls)? I believe I've seen versions of those with reliable "T' factory codes, but now it's on me to come up with proof! "


Another question relevant to this thread is: which of all these fine valves, if any, actually match up on physical characteristics?

I think these two points are best taken together. Only by using our collective interest and various knowledge bases, can this miasma of confusion actually start making any sense whatsoever. I personally love burrowing down into the real details as we're all doing here, I always learn something, always.


Regarding the seemingly compromised Tungsram circle logos, those tubes were advertised as Mullards, make of that what you will.

I think to an awful lot of sellers (and not only the absolutely uninformed) BVA...British Made...Made in England = Mullard.

:salude
 

Deus91

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Yes, and those look to be British Tungsram.

JOB-LOT-OF-10-BRITISH-MADE-6V6G-BRIMAR-_57.jpg


Got any shots looking down at the tops of 'em? Thanks-
Jeff, here is a pic of the tops of my ZA 5306 and a pair of Phillips branded 6V6G.
Off topic, but was wondering if you have ever had or seen a Mullard branded 5Y3G tube?
These are also from my stash.
uCECGTX.jpg
CHrw3N9.jpg
4IaE1kf.jpg
Ps0cX0b.jpg
 

ourmaninthenorth

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" Beautiful quad of GEC military. "

See, that's the thing . . . they all have T codes specifying made by British Tungsram.

As I'm sure you know Jeff, British Tungsram is in itself somewhat of a misnomer, A subsidary wholly owned by it's Hungarian parent company - they were at best assemblers of parts in their Tottenham factory sourced mainly from outside the UK. Some material suggests that they merely "sealed up" other manufacturer's process. They were never granted BVA membership. Assembled in Britain, I suggest largely not made in Britain.

They were under fiscal control by Phillips by 1952, and under managerial control by Mullard in the same year.

I highly doubt that Tungsram made any of the valves, as a complete industrial process, in house that bear their marks.

My Point? Their markings are to be taken with a large pinch of salt in establishing who actually manufactured the valve.
 

Jeff West

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Lots of good things to consider here, although it's becoming an ongoing project!

Deus- thanks for the great photos. I'll try to come back to those.

Paul- Just a few comments first. What we know about both the N. American and U.K. governmental standards and markings from multiple documented sources is that they did tend to take very seriously the accuracy of the info of origin that was a part of meeting various standards and recording same. This was a practical matter given the potential roles of the valves. Just as one example in the U.S., JAN compliance certification and documentation of same on the tube for a specific JAN tube type was specific to a site of manufacture, not just a manufacturer. Thus, for instance, in the late '50s RCA had four different tube-making factory sites across three states, but JAN certification for 6V6GTYs was limited to the plant in Woodbridge, NJ. So they couldn't shift production of these to Harrison or Indianapolis as needed, even though 6V6GTs were made at the latter RCA factories and production of non-mil versions was shifted routinely. When issues came up, they wanted to know when and where they originated. There are other interesting and sometimes compulsive examples. In the British theater, my understanding is that there was also thorough and protective attention to these details, although as you suggest, on both sides of the Atlantic things could get complicated by various aspects of industrial and corporate inbreeding. But, I would argue that governmental documentation with respect to origin and date of registration in general was enforced to be relatively valid and reliable, certainly compared to most other info printed on tubes! In many cases, it seems the best we can get, when available.

And we do know that point of origin for a valve in both systems was specifically defined as the place of final pumping and sealing. So, as you said, this leaves open the question of where components were sourced, fabricated and/or assembled, up to a point. Tungsram is certainly a good example, although I would argue not a totally simple one as things evolved. The Tottenham factory opened in 1934, and the situation you described characterized the early years for certain, but multiple references indicate that they were building at least some tubes there in house from scratch starting years before Philips took controlling interest in 1952. Also, it is documented that production at Tottenham ceased in April 1956 when the factory closed, and distribution of valves made there ceased the following year; after that, the Tungsram labelling lived on as a Philips brand for several more years, we've had some forum threads about Blackburn 12AX7s with interesting Tungram logos, etc.

I guess I'm not certain if you were suggesting that the factory codes in general are suspect, or that Tottenham in particular was squirrely.

But either way, in the time frame we're considering, neither Tungsram nor Philips were GEC, so it's interesting.

At this point, I myself am not considering it definite that the T coded versions depicted are necessarily of the same origin as the GECs depicted, but the similarities are compelling . . .

One other thing to consider fwiw, Philips owned the international patents on pentodes, that was their main thing re:power tubes, true pentodes with a screen grida la EL37, EL34, EL84, etc. (spawning, of course, the development of the beam tube by competitors, M-OV and RCA). It does seem a useful generalization that whenever they got into non-pentode applications under their brands in those days, you tend to start seeing deviations from usual Philips production chains.
 
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Jeff West

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Hey deus91- Your T coded 6V6Gs certainly look like the ones in post #19. The longer "wings" on the outside up top were called "snubbers" by Tung-Sol, they're mica and contact the inside of the glass bulb, to support positioning and stability of the internal structure. The "inside wings" are metal radiators welded to the copper grid rods, to assist heat dissipation from the grid. As I think was mentioned above, some tubes that had these had a one-piece U-shaped radiator connecting both grid rods.

Your later Philips branded 6V6Gs look different in detail, but sleek and ready to rock, I'm sure!

The 5Y3G also looks great. Does it have anything on the back? No, I don't think I have one of those. I do have some varied 5Y3Gs that also have pleasing shapes and perform well, more stylish perhaps than a pedestrian half-baked 5Y3GT in certain amps, if you have the room.

Thanks again for posting photos.
 

Deus91

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Jeff, thanks for the detailed response. You are correct again, as the Phillips have a one piece U shaped radiator.
I have 3 of the Mullard branded 5Y3G rectifiers, PM me if you want one for your collection and I will send you
one of the unopened ones. You just pay for the shipping.:)
Speaking of Mullard rectifiers here are two pairs of GZ34 from 1958 and 1961. Both pair are "Fat Base" f31.
ju7OplZ.jpg
 

ourmaninthenorth

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Jeff.

It's such a privilege to be part of these discussions, particularly with people with such a profound grasp of the subject matter.

However I feel completely responsible for taking this thread down a completely different path than intended. The contributors questions were for you, and I've incongruously butted in. Rude of me.

I have observations to make on the minutiae, but they can wait until another time, perhaps we can reconvene on this at a future time Jeff?

Gentlemen, my apologies for the derail (for that is what I think my contribution is) on your fine thread.

:salude
 

Jeff West

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Hi Paul- Speaking just for myself, no apologies necessary and it's my genuine hope that you won't feel negative overall about any of this discussion including any "expanding of the scope of the investigation", that happens all the time with vintage tube threads! (which admittedly are often held in forums other than LPF). I know I'm culpable as hell in that regard. For that matter, I hope the stuff I'm writing doesn't come across as simultaneously pedantic and obsessively deranged, although I suspect sometimes it does (like when I read it later!). AFAIC, the statute of limitations on a specific page to me in this thread ran out long ago, a few years after 2012. Seriously, always appreciate your good input and knowledge (which among many other things helps me see some of my areas of ignorance or misdirection), and chances to discuss various topics of specialized interest here. And you're one of the least rude forum members I can think of!

Oh yeah, Oatie's tubes . . . I guess the Mazda angle awaits additional exploration!

But I'm with you that other things are calling and we may have to come back later . . .

Meanwhile, I can't help thinking about the timeline of those 6V6Gs, like when the GEC oval decals started in use . . . the progression of things might be an important aspect of trying to understand the sources . . .
 

ourmaninthenorth

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Hi Paul- Speaking just for myself, no apologies necessary and it's my genuine hope that you won't feel negative overall about any of this discussion including any "expanding of the scope of the investigation", that happens all the time with vintage tube threads! (which admittedly are often held in forums other than LPF). I know I'm culpable as hell in that regard. For that matter, I hope the stuff I'm writing doesn't come across as simultaneously pedantic and obsessively deranged, although I suspect sometimes it does (like when I read it later!). AFAIC, the statute of limitations on a specific page to me in this thread ran out long ago, a few years after 2012. Seriously, always appreciate your good input and knowledge (which among many other things helps me see some of my areas of ignorance or misdirection), and chances to discuss various topics of specialized interest here. And you're one of the least rude forum members I can think of!

Absolutely not pedantic or deranged, more like exceptionally informed. What you bring expands knowledge bases across the board. I'm grateful for the material, it pressure tests my own understandings ie it makes me think.

Oh yeah, Oatie's tubes . . . I guess the Mazda angle awaits additional exploration!

I think the U radiator rules out my assertion of GEC - I simply missed the feature in Oatie's superb pictures, good eyes Jeff.

But which Mazda entity is the next question? BVA (Ediswan), French, or Belgian? And why labelled as Mullard?...particularly in light of their protectionist moodiness ( mirrored in the BVA across the board from inception ) in allowing other manufacturer's valves to bear their mark. Note this injunction they sought in 1960...


time056a.jpg


I think it goes to the point I was attempting to make earlier, that there were so many inter and intra twists and turns in this industry, that nailing down who did what and where, is often not as black and white as the codings and marks would suggest. The BVA was cartel-esque in it's existential commerciality. I've been trying for a number of years to burrow into the hugely complicated time lines and relationships..it's mind boggling. The BVA were alive to protecting it's market on it's own terms. A rather interesting piece of advertising giving a flavour of how they saw it perhaps?...

November 1963 Radio & Electrical retailing magazine.


time185a.jpg


time185b.jpg


But I'm with you that other things are calling and we may have to come back later . . .

Meanwhile, I can't help thinking about the timeline of those 6V6Gs, like when the GEC oval decals started in use . . . the progression of things might be an important aspect of trying to understand the sources . . .

I personally think that is the whole rub right there...the timeline. It's often like trying to do a 1000 piece jigsaw without the picture on the lid. Difficult and fascinating in equal measure.

When I have a little more head room, I have loads of material to share with you Jeff. I'll most assuredly like to get something going in the future.

Until then....

:salude
 

Jeff West

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Hi Deus91- Thanks very much, that’s a very nice offer.
Regarding the big base GZ34s, I have a ‘64 AC50 head that I got about 30 years ago, it had a working GE GZ34 labeled Lindal as I recall, but I swapped it for a big base Mullard scored at a hamfest. It’s still working great. As Paul said, some of these working tubes can outlive us.

I’ll be in touch to talk tubes a little more.
 

Jeff West

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Paul- That's great, I'm glad to know a BVA researcher!

Thanks for sharing literature, now and in future.

Although I haven't been in touch for awhile, there's an interesting and friendly gentleman in London who was an EE and apprenticed then worked for M-OV at Hammersmith and other sites 1956-61, he had literally applied date stamps to KT66s right after they were sealed, supervised engineering changes, etc. His name is Bryan Lockey, and he was very forthright in sharing info to best of his recollection, I even got him responding on the Marstran forum at one point. If he's still around, maybe it's time to reconnect, he might have BVA perspective. Even if not, I can send some old e-mails likely of interest.
 

Deus91

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Paul- That's great, I'm glad to know a BVA researcher!

Thanks for sharing literature, now and in future.

Although I haven't been in touch for awhile, there's an interesting and friendly gentleman in London who was an EE and apprenticed then worked for M-OV at Hammersmith and other sites 1956-61, he had literally applied date stamps to KT66s right after they were sealed, supervised engineering changes, etc. His name is Bryan Lockey, and he was very forthright in sharing info to best of his recollection, I even got him responding on the Marstran forum at one point. If he's still around, maybe it's time to reconnect, he might have BVA perspective. Even if not, I can send some old e-mails likely of interest.
Jeff, in honor of Mr. Lockey and the mighty KT66. From NATO surplus stock.
OrF2cLa.jpg
47HLwNj.jpg
sO3JElf.jpg
QYaJXuQ.jpg
 

Jeff West

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Beautiful classics!


*Codes confirm valves made at Hammersmith and established by British authority to meet qualifications for Joint Service Specification K1001/1006 as of Oct, 1957, for these particular specimens. Strictly speaking that's the date of qualification, not manufacture; when actual date of manufacture is also present on these IME it's usually just a month or three before, but sometimes longer. I've been looking at GEC decals on dated KT66s and others, and this rectangular style seems to have become common in about 1957, as here, and to have been supplanted by the more oval version in 1958 and on for awhile. There was also a larger, more florid oval GEC in use in '56-'57 that I've seen mainly on very early KT88s, sometimes KT66s. Notice of exceptions/corrections to above welcomed! This decal business might be relevant to above discussion of 6V6Gs in this thread, in that it could suggest a lower limit for when GEC decals were placed on undated 6V6Gs like those in post #15 above, sometime after manufacture . . .
 
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