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  1. #1
    Les Paul Forum Member bluesforstevie's Avatar
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    Paging Jeff West: Mullard Tube Question??

    What is the deal with the Mullard Yellow Print tubes? Most of them seem to be mid 60's examples and they tend to have two initials on them as well? Any way to decode those? For instance, I've a GZ34, yellow print with the initials "M" and "H" on the either side of the BVA oval.

    Is it the distributor? Where they were silkscreened? Anyway. Thanks in advance!!

  2. #2
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Hey Dan- I've heard info about this from various sources, inc UK Vintage Radio guys, but I'm not sure that anything is nailed down 100% certain regarding the yellow print on seemingly standard Mullards (and not counting "10M").

    Having said that, I think it may likely reflect intended sales/use trajectory of the tubes. Specifically, there's evidence that the yellow labels were generally intended for OEM use in equipment and generally provided in egg crate or bulk packaging (and found as stock in equipment), whereas those valves for retail sale individually packaged would be white label. Among other things, this was apparently the understanding of numerous separate people involved in electronics and audio in Britain in the early '60s period.

    Contrary to what is sometimes claimed, it clearly was not just a period of time in which they switched to yellow, you can find white and yellow with the same etch codes, etc.

    There are lots of exceptions to the above claim: white label tubes seemingly original in OEM equipment, and yellow label in individual boxes that seem original, etc. The explanation is said to be that they couldn't always uphold the distinction, depending on stock on hand, and eventually abandoned it in the late '60s or before for that reason.

    Incidentally, several U.S. tube manufacturers are known to have used different printed coding details in the '50s and '60s for OEM vs. retail bound tubes that were otherwise identical. These include RCA and Tung-Sol, for which period written company records on this topic exist. On RCAs it included the presence vs. absence of a "dash" in the printed date code, on T-S it included whether certain letters in "Made In USA" printing were slanted or not!

    Other things that have been claimed about the Mullards include that the yellow ink reflected a different warranty. This could be true, but might actually be just another facet of the above OEM distinction, in that many tube manufacturers did have different warranties on OEM vs. retail sales, related to replacement period, etc. This also might fit with the fact that yellow label have the additional letter codes while the white do not (see below).

    Interestingly, among vintage British wireless type guys, common lore seems to have been that the yellow label specimens didn't last as long, raising the suspicion that they somehow might be "seconds" (or, at least, not "firsts"). Do they get a premium or reduced price on E-bay these days?

    Regarding the "side letters" surrounding BVA, these do appear to reflect the year and month that the yellow was printed, or possibly that the tube was intended to ship, and/or that the warranty period might go into effect. As such, when decoded they should fall at least a little later than the etch codes, or possibly considerably later in some cases. I have some notes which I didn't credit for source unfortunately that suggest that the letter on the left as you face the logo is the year, with J said to be 1962, K='63, L='64, M='65. Months on the right appear to fit nicely with A=Jan, B=Feb. We'd have to see if anyone's got an "M" on the right to know if they skipped "I"; probably not, going by the Philips etch code practice.

    With your M and H on the GZ34 decoded as Aug '65 per the above, does that seem reasonable with the other codes on that tube? I haven't really checked the above decoding out thoroughly, it might be off.

    You see the occasonal '50s made Mullard with yellow printing, possibly the above letter codes can be traced backwards to go earlier.

    Anyone with more/better info please step up!

    Oh, there's also this: http://www.tube-classics.de/TC/Tubes...lipscolors.htm

    But I dunno . . . even if true it may not apply to our fave 12AX7, EL34, GZ34, etc. Also, all of those are Valvo branded. And don't have the side letters.
    Last edited by Jeff West; 05-11-12 at 03:04 PM. Reason: added color

  3. #3
    Les Paul Forum Member bluesforstevie's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Wow...Looks like I paged the right guy. Thanks Jeff!!!

    You're right on with the initials as the date code of the "M" and "H" valve is B5H1; 1st week of Aug. 1965!!!

    You're a wealth of info my friend!!

  4. #4
    Les Paul Forum Member
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    Re: Paging Jeff West: Mullard Tube Question??

    Jeff is the man!

  5. #5
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    I must have been drinking lots of coffee that day back in 2012, Deus!

  6. #6

    Re: Paging Jeff West: Mullard Tube Question??

    Quote Originally Posted by bluesforstevie View Post
    What is the deal with the Mullard Yellow Print tubes? Most of them seem to be mid 60's examples and they tend to have two initials on them as well? Any way to decode those? For instance, I've a GZ34, yellow print with the initials "M" and "H" on the either side of the BVA oval.

    Is it the distributor? Where they were silkscreened? Anyway. Thanks in advance!!
    GREETINGS, EFFECTIVELY WAS IN THE DECADE OF THE 60TH BUT THE INITIALS M AND H COME DIRECTLY FROM THE FACTORY THAT ASSEMBLIES FROM THE INITIALS OF THEIR FOUNDERS.

  7. #7
    Les Paul Forum Member
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    Re: Paging Jeff West: Mullard Tube Question??

    Not to HiJack the thread,

    Jeff, about what year do you think these Mullard 6V6G tubes were made? I have two sets of these and a set of GEC that look almost the same. Some say they are Marconi tubes, would be nice to know a little more. I tried a set in an old tweed Deluxe and they sound great. I use the Raytheon 6087 rectifier and 5751 in V1 and V2 and it's a magic combo.

    I'm building a small dual bias pot board so I can adjust the bias on my 50 watt Marshalls for each tube. A good way to use some old stock EL34 Blackburns and match the bias with a pot for each EL34 socket. When the board is done I will share the info to the gent who builds them in a small turret board. The early JMP50 amps with the stand-up PT have plenty of room to install the dual bias pot board. The Laydown smallbox chassis will need some new stand-offs to make it work. Love the EL34 Blackburn tone.







  8. #8
    Les Paul Forum Member corpse's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Time capsule stuff. Wow.

  9. #9
    Les Paul Forum Member ourmaninthenorth's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    I wouldn't bat an eyelid if these had GEC stickers on them, and were mentioned to be from the 40's.
    Shakespeare walks into a pub, the Landlord says "get out, you're Bard"

  10. #10
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Can be hard to ID some 6V6Gs especially without in-hand inspection, but my best educated guess for actual manufacturer of origin for those would be British Tungsram, 1950s.

    Under other liveries (e.g. CV509), I think you'll find these with British "T" codes for Tottenham/British Tungsram, and the "up arrow" mark; unlike lots of codings/writings on tubes, those former can be considered to reflect the factory of origin accurately (unless, of course, the printing itself is counterfeit). You do see them with genuine "GEC" oval decals as well. I guess you have some of those too, Oatie?

    Pretty much all the GEC 6V6GTs I have or have seen were made by either Tungsram or Brimar in UK, although I can't say that's exhaustive. Maybe some Ferrantis? I'm confident these above are not Brimars, and definitely not Canadian Marconis.

    Not all British Tungsram 6V6G versions look alike, however, inside or out.

    Great valves, all of the above. I really love the Brimars. The UK Tungsrams also sound great, and many look especially cool, like mini KT66s.

    Btw, if you encounter "ZA 5306" on mil or other versions of British 6V6Gs like these, confusingly this does not indicate manufacture by Marconi-Osram Valve via the "ZA", nor is the "5306" a date code indicating early 1953. Rather, ZA 5306 was a govt "cross reference store number" that did not reflect a specific factory or date. However, note that some of these with that code also have additional legitimate date codes indicating 1953!

    Addendum: I was looking again at those photos, and some things don’t look quite right for Tungsrams, have a few questions
    Last edited by Jeff West; 07-12-19 at 08:25 PM. Reason: Meanwhile, I was still thinking . . .

  11. #11
    Les Paul Forum Member
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    Re: Paging Jeff West: Mullard Tube Question??

    I have 2 sets of the Mullard coke bottle and 2 sets of the GEC unused. They came from an old Hong Kong gent dealer about 20 years ago.
    The GEC tubes have brown boxes that look like Mil Spec writing and are packed with that old horsehair looking matting. The Mullards have the corrugated cardboard wrapped in paper inserts. I also got some great dual top getter Mullard GZ34 tubes from him with the same type logo screened. They make great tone in the tweed Deluxe. I still have a couple dozen RCA 6V6GTA tubes and they are my main tubes I use.
    I like the GE or Raytheon 6087 rectifier and two 5751 in the Deluxe.



  12. #12
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Cool- Do The GECs look exactly like the Mullard? Anyhthing interesting stamped on the GEC boxes, or the tubes themselves for that matter?

    And, if you remember, is the GZ34 f31, f32 or?
    Last edited by Jeff West; 07-12-19 at 11:26 PM.

  13. #13
    Les Paul Forum Member
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    Re: Paging Jeff West: Mullard Tube Question??

    Jeff. here are a pair of 6V6G with the "ZA 5306" lettering from my stash.
    You referred to them in your earlier post.

  14. #14
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Yes, and those look to be British Tungsram.



    Got any shots looking down at the tops of 'em? Thanks-

  15. #15
    Les Paul Forum Member ourmaninthenorth's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Here's a couple of shots that lead me to believe that they're GEC's.

    Note the cooling fin configuration in comparison to the Mullards.

    These are not my valves..stock photos.









    And showing the military/government designation...





    Fascinating stuff this isn't it?

    Last edited by ourmaninthenorth; 07-13-19 at 06:25 AM. Reason: made a bollocks of the pictures.
    Shakespeare walks into a pub, the Landlord says "get out, you're Bard"

  16. #16
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    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? I believe I've seen versions of those with reliable "T' factory codes, but now it's on me to come up with proof!

  17. #17
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Thanks for great photos, Paul. Can be fascinating, although maybe at some points be better to just play on . . .

    I did submit smething in response, but apparently waiting in the Moderator queue, hopefully will come up.

  18. #18
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    In the meantime, some other food-for-thought photos, if they go thru:


    above via KCANOS; has U-shaped grid rod radiator like Oatie's appear to
    To give credit to Mike at KCA as due,I believe he has already said in the past that he thought Oatie's are just like this


    Above resemble Paul's GEC photos? Look to have British Tungsram logos with the "Tungsram" worn off or removed


    This one above may have some provenance as a British Marconi product. And the codes shown could indicate a 1948 date of birth.




    The above are definitely "T" coded, resemble Paul's GEC photos above(?)


    Above we get Mullard labelling, but there are some differences from Oatie's-
    Last edited by Jeff West; 07-13-19 at 03:06 PM.

  19. #19
    Les Paul Forum Member ourmaninthenorth's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Quote Originally Posted by Jeff West View Post
    In the meantime, some other food-for-thought photos, if they go thru:


    above via KCANOS; has U-shaped grid rod radiator like Oatie's appear to


    Above resemble Paul's GEC photos? Look to have British Tungsram logos with the "Tungsram" worn off or removed

    Food for thought indeed Jeff. Great research.

    The Mazda I think is French made, or one of those Mazda's that Brimar had some hand in, and were British made. Simple stuff this...yeah right...

    The quad set are equally confusing, Tungsram style half worn off logo ( a little too uniformly for my liking ) with a Haltron* type face on the 6V6G script, with GEC physical characteristics.

    The third one - the picture makes the physical details hard to see, so don't know. Very early coding though. One to ponder in hand methinks.


    * Haltron - not a valve manufacturer, they bought valves in from various sources and re-badged them with their own trade name.
    Shakespeare walks into a pub, the Landlord says "get out, you're Bard"

  20. #20
    Les Paul Forum Member ourmaninthenorth's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Quote Originally Posted by Jeff West View Post









    The above are definitely "T" coded, resemble Paul's GEC photos above(?)

    Beautiful quad of GEC military.

    I personally don't think you can buy better than these.

    They'll out live us all...
    Shakespeare walks into a pub, the Landlord says "get out, you're Bard"

  21. #21
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    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.
    Last edited by Jeff West; 07-13-19 at 03:32 PM. Reason: The beat goes on . . .

  22. #22
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    " Beautiful quad of GEC military. "

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

  23. #23
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??



    Above Brimar made, for certain.

  24. #24
    Les Paul Forum Member ourmaninthenorth's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Quote Originally Posted by Jeff West View Post
    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.
    Shakespeare walks into a pub, the Landlord says "get out, you're Bard"

  25. #25
    Les Paul Forum Member
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    Re: Paging Jeff West: Mullard Tube Question??

    Quote Originally Posted by Jeff West View Post
    Yes, and those look to be British Tungsram.



    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.

  26. #26
    Les Paul Forum Member ourmaninthenorth's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Quote Originally Posted by Jeff West View Post
    " 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.
    Shakespeare walks into a pub, the Landlord says "get out, you're Bard"

  27. #27
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    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.
    Last edited by Jeff West; 07-14-19 at 12:01 AM. Reason: rabbit holin'

  28. #28
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    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.

  29. #29
    Les Paul Forum Member
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    Re: Paging Jeff West: Mullard Tube Question??

    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.

  30. #30
    Les Paul Forum Member ourmaninthenorth's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    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.

    Shakespeare walks into a pub, the Landlord says "get out, you're Bard"

  31. #31
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    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 . . .

  32. #32
    Les Paul Forum Member ourmaninthenorth's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Quote Originally Posted by Jeff West View Post
    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...




    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.






    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....

    Shakespeare walks into a pub, the Landlord says "get out, you're Bard"

  33. #33
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    Hi Deus91- Thanks very much, thatís a very nice offer.
    Regarding the big base GZ34s, I have a Ď64 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. Itís still working great. As Paul said, some of these working tubes can outlive us.

    Iíll be in touch to talk tubes a little more.

  34. #34
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    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.

  35. #35
    Les Paul Forum Member
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    Re: Paging Jeff West: Mullard Tube Question??

    Quote Originally Posted by Jeff West View Post
    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.

  36. #36
    Les Paul Forum Member Jeff West's Avatar
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    Re: Paging Jeff West: Mullard Tube Question??

    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 . . .
    Last edited by Jeff West; 07-15-19 at 11:21 PM.

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