[tintinsnowydog]

Been a bit quite here recently! Here is a really interesting find today on this pair of Mullard 6J5G. The construction looks identical to the MOV L63/6J5G we know and love, with the grey glass and the distinctive top mica construction as viewed from the top. But I've never seen them with brown bases nor Mullard print.

The white print on the rear glass should have been revealing- CV193(2) = 6J5G, KB/D(A) = factory code of Mullard Blackburn. However the date code is confusing me- BK(?) would suggest 1946 production, but the factory code for Blackburn pre 1951 should be A instead of DA. The only other possibility is that it is a printed 8, but as far as I know the Mullard date codes were only ever 2 letters, no numbers used. Rear print on the right tube has rubbed off completely unfortunately so no second reference. Would be interested to hear others' thoughts on these. Also interesting is the letter B printed on the spigot base, perhaps denoting Blackburn?

First impressions paired with GEC 6AS7G are fantastic, I am not sure if it is mental bias (I am leaning towards it is) but they seem to be sounding a little warmer to me than the MOV L63. This should be the case if they were in fact made at Blackburn instead of MOV Hammersmith. I need more time to compare between them to make a definitive judgement. I have L63 from the same/very similar vintage to compare to minimise variation. At the end of the day, there is no going wrong with these British L63/CV1932/6J5G whatever they decide to conceal themselves as, some of the best in this family of tubes

 

[leftside]

Been a bit quite here recently! Here is a really interesting find today on this pair of Mullard 6J5G. The construction looks identical to the MOV L63/6J5G we know and love, with the grey glass and the distinctive top mica construction as viewed from the top. But I've never seen them with brown bases nor Mullard print.

The white print on the rear glass should have been revealing- CV193(2) = 6J5G, KB/D(A) = factory code of Mullard Blackburn. However the date code is confusing me- BK(?) would suggest 1946 production, but the factory code for Blackburn pre 1951 should be A instead of DA. The only other possibility is that it is a printed 8, but as far as I know the Mullard date codes were only ever 2 letters, no numbers used. Rear print on the right tube has rubbed off completely unfortunately so no second reference. Would be interested to hear others' thoughts on these. Also interesting is the letter B printed on the spigot base, perhaps denoting Blackburn?

First impressions paired with GEC 6AS7G are fantastic, I am not sure if it is mental bias (I am leaning towards it is) but they seem to be sounding a little warmer to me than the MOV L63. This should be the case if they were in fact made at Blackburn instead of MOV Hammersmith. I need more time to compare between them to make a definitive judgement. I have L63 from the same/very similar vintage to compare to minimise variation. At the end of the day, there is no going wrong with these British L63/CV1932/6J5G whatever they decide to conceal themselves as, some of the best in this family of tubes

I think that when Mullard used the military designation "CV", then "DA" does indeed = Blackburn. Nice find! They could still be GEC tubes and rebranded/reprinted by Mullard. Who knows...

 

[triod750]

Does anybody recognize this tube, branded Philips. Who might have made it?

I have just bought it, out of curiosity, but it isn't delivered yet. Also bought another, supposed to have been manufactured by National Union.

Photos from the auction.

 

[therremans]

Does anybody recognize this tube, branded Philips. Who might have made it?

I have just bought it, out of curiosity, but it isn't delivered yet. Also bought another, supposed to have been manufactured by National Union.

Photos from the auction.

What is the tube model/type of the Phillips?

 

[Xcalibur255]

The mica says 1950's Raytheon to me, but don't take that as gospel because I'm not completely certain.

 

[mordy]

Does anybody recognize this tube, branded Philips. Who might have made it?

I have just bought it, out of curiosity, but it isn't delivered yet. Also bought another, supposed to have been manufactured by National Union.

Photos from the auction.

I've got a mate for you Triod750:

This is a Super Silvertone 6J5GT from November 1943. And thanks to X255 I now know that it is a Raytheon. Codes are M-R and L3.
M-R means manufacturers replacement - a certain proportion was allocated for civilian use of WW2 tube production and the M-R designation was in effect between 1942-45. If I count the months on my fingers and skip the letter I (looks like 1) the letter "L" is 11 = November.
Silvertone indicates that it was sold by Sears department store.

 

[triod750]

I've got a mate for you Triod750:

This is a Super Silvertone 6J5GT from November 1943. And thanks to X255 I now know that it is a Raytheon. Codes are M-R and L3.
M-R means manufacturers replacement - a certain proportion was allocated for civilian use of WW2 tube production and the M-R designation was in effect between 1942-45. If I count the months on my fingers and skip the letter I (looks like 1) the letter "L" is 11 = November.
Silvertone indicates that it was sold by Sears department store.

If you have only one, this means that I am supposed to ship mine to you since you had your's first .

 

[mordy]

If you have only one, this means that I am supposed to ship mine to you since you had your's first .

Or maybe the opposite?

 

[mordy]

Or maybe the opposite?

I've got a mate for you Triod750:

This is a Super Silvertone 6J5GT from November 1943. And thanks to X255 I now know that it is a Raytheon. Codes are M-R and L3.
M-R means manufacturers replacement - a certain proportion was allocated for civilian use of WW2 tube production and the M-R designation was in effect between 1942-45. If I count the months on my fingers and skip the letter I (looks like 1) the letter "L" is 11 = November.
Silvertone indicates that it was sold by Sears department store.

However, I looked through a bunch of pictures of Raytheon 6J5GT tubes. Most of them look very different. The closest thing to the Philips/Silvertone tube that I found is this:

But the micas on the Raytheon only have four little pegs - the Philips/Silvertone tubes have seven pegs on the micas.
So the mystery remains....

 

[triod750]

We love mysteries. That is what prevents us from falling asleep at night, wasting our time...

 

[therremans]

My Raytheon’s have the same design but my micas have less teeth. If you have a 6J5, I asked as you also posted a 6C5 with the same post.

 

[triod750]

If you are asking me - the Philips posted is a 6J5GT - I mistakenly left out that information. I don't know when it will be delivered. He stores them for me and I buy more eventually and save on shipping cost.

 

[Xcalibur255]

It's entirely possible for both mica variants to be Raytheon. You can see both of those design variants in their 6SN7s too. But again I'm not certain it's just my best guess. I believe the one with fewer teeth would generally be older in age.

 

[jonathan c]

I believe the one with fewer teeth would generally be older in age.

Except for infants…

 

[Xcalibur255]

I finally broke down and picked up a pair of Marconi L63 grey glass. It has been a while since I have listened to my well used B65 but my gut feeling is that tonally the two are close to identical. The usual 6J5 advantages, such as improved separation and imaging, apply of course. I fully expect the prices on these to keep quickly climbing skyward as more and more people realize they can get the B65 sound through adapter usage.

To my ears they sound substantially different from the GEC L63 straight glass too. The presentation is quite a bit different IMO. The GEC presents with a much denser stage and dare I say is superior at pulling out low level texture detail. The Marconi grey glass is quite a bit more open and airy. Hard to really call one better than the other..... I think a better way to think of it would be in terms of what headphones you are matching them to. Paired with something that is already very open sounding like an HD800 I could see the Marconi leaning to the thin side, so the GEC would probably provide a nice counterbalance there for example.

The coke bottle Raytheons, especially the round plate version, are actually fairly close to the Marconi tonal presentation too. Not super close, but there is definitely a resemblance compared to some of the others that are clearly different flavors. Mostly the Marconi is just one step higher in overall refinement and finesse, but you certainly pay a premium for what is ultimately a fairly subtle improvement.

I'm glad I stopped hunting for a pristine pair that I would then not want to actually use in an amp. The ones I have test well but kind of look like mutts so I will have no qualms actually running them when I feel like it.