[JKDJedi]

I just wanted to add that Western Electric tube data is pretty rare. Most of their work was for the government and bell systems. I have never seen anything post 50's except for maybe a brochure about new equipment. They weren't trying to sell tubes to the public so I doubt they would have boasted about perfectly matched triodes or having the highest transconductance, but anything is possible. Think of things this way. Most 60's RCA 12AX7's that I test are in the 1400 to 2000 MICROMHOS range per triode on my favorite tube tester. Most 70's USA made Sylvania 12AX7 tubes (the ones with the non symmetrical plates) are in the 2000 to 2500 MICROMHOS range. Both good tubes, one just has a higher transconductance. There are other factors involved. A 12AU7 has a higher transconductance than a 12AX7, but it would make a horrible substitute in a circuit designed for a 12AX7.

The one I have (just found it it) is 53' I'd have to find the info/article/website where I found the mention of this " utmost reliability in respect to triode balance is required" . when it was talking about the 421a. Got a dinner party soon so won't be till later. I'm surprised I still have the data sheet..lol, I deleted so many articles I had saved.

 

[JKDJedi]

I thought I had lost my 6520's.. I did sell one, and thought the other got damaged on a botched sale (still confused on that whole thing, did it revive itself?). I haven't been rolling tubes for a bit. And for the longest perceived that I had my Chatham 5998 in my amp. Low and behold.... to my surprise.

 

[Electron Mitigator]

I thought I had lost my 6520's.. I did sell one, and thought the other got damaged on a botched sale (still confused on that whole thing, did it revive itself?). I haven't been rolling tubes for a bit. And for the longest perceived that I had my Chatham 5998 in my amp. Low and behold.... to my surprise.

Very Nice. I contacted the person I know that had that sleeve of 5 and he still has them. All 5 tubes are perfectly matched per side and to each other. Only problem is he won't sell just one and want's quite a bit for the sleeve. This thread has gotten me interested in building one of these for myself, but the two 5998 tubes I found in my stash don't have very well balanced halves. They look heavily used and probably came out of something I worked on years ago.

 

[JKDJedi]

Has

Has me looking too, don't need 5 of them. I found one in China somewhere that looked suspicious, so passing on that one. I had a very strong 421a, let it go to early. Prices are insane right now. Another 6520 or 421a would be nice under the tree.

 

[Electron Mitigator]

What are some of the favorite headphone being used on amps with these tubes?

 

[JKDJedi]

What are some of the favorite headphone being used on amps with these tubes?

Anything with 300 impedance and up, highly recommended. Having said that, I was surprised that my Fedilio X2 faired well. I'm not a clinical listener, that's for the recording studios. I'd rather enjoy my music after a drink or puff.

 

[dpump]

I have a pair of 5998 labeled JAN-CTL-5998. The only other number is 543. Trying to find out what the 543 means.

 

[JKDJedi]

I have a pair of 5998 labeled JAN-CTL-5998. The only other number is 543. Trying to find out what the 543 means.

my guess 1953 (or 63) week 54

 

[Electron Mitigator]

I am selling 4 beautifully matched NOS Boxed Westinghouse 6520 Domino Plate tubes. Anyone interested please contact me.

 

[JKDJedi]

I am selling 4 beautifully matched NOS Boxed Westinghouse 6520 Domino Plate tubes. Anyone interested please contact me.

PM Sent (and thinking no such thing as a Westinghouse 6520) oops...I stand corrected, there is a Westinghouse 6520..wow.. take a look guys these are legit!

 

[Electron Mitigator]

I have a pair of 5998 labeled JAN-CTL-5998. The only other number is 543. Trying to find out what the 543 means.

Seeing the tube would be helpful. Most JAN stuff is from the 50's. It was a military term. If your number is a date code 50's tubes usually are in the format YMM. In the 60's it is YYMM. If that number is a date code I would say the 43rd week of 1955.

 

[Electron Mitigator]

I should add that tubes weren't branded at the time of manufacture. They were stored on shelves in very large lots and branded when branded stock ran low. A specific tube, say 6L6GC, wasn't built daily. It might have gotten built once a year or less depending on the tube, the demand and what decade. Branded lots were done in large amounts too, as you wouldn't want to be changing silk screens, etc. after every tube. In the 50's and 60's those dates could be close. In the 70's and 80's there are tubes branded several years after they were built. In the 70's and 80's you can even find close sub's branded as something else that a company needed at the time. On the far side of that you can find tubes built in the 70's branded in the 80's and 90's as STR (Special Tube Reserves). Not all STR tubes are of this ilk, however. In more recent times companies have been using the STR moniker (Special Tube Request) on more recently built tubes. This is a really good place to mention one more thing. Over the last 30 years I have kept every faulty or unusable tube I have encountered. Probably close to 300 tubes. In that box only about 20 tubes are pre 1980 built. With those stats a 60 year old tube has a 15 times greater chance of still being good today compared to a 15 year old tube. Go figure.

 

[JKDJedi]

I should add that tubes weren't branded at the time of manufacture. They were stored on shelves in very large lots and branded when branded stock ran low. A specific tube, say 6L6GC, wasn't built daily. It might have gotten built once a year or less depending on the tube, the demand and what decade. Branded lots were done in large amounts too, as you wouldn't want to be changing silk screens, etc. after every tube. In the 50's and 60's those dates could be close. In the 70's and 80's there are tubes branded several years after they were built. In the 70's and 80's you can even find close sub's branded as something else that a company needed at the time. On the far side of that you can find tubes built in the 70's branded in the 80's and 90's as STR (Special Tube Reserves). Not all STR tubes are of this ilk, however. In more recent times companies have been using the STR moniker (Special Tube Request) on more recently built tubes. This is a really good place to mention one more thing. Over the last 30 years I have kept every faulty or unusable tube I have encountered. Probably close to 300 tubes. In that box only about 20 tubes are pre 1980 built. With those stats a 60 year old tube has a 15 times greater chance of still being good today compared to a 15 year old tube. Go figure.

They sure don't make them like they use too.

 

[JTbbb]

Hello there all,

Just what do I have here? Clear top, bottom D Getters and rectangular top mica supports. The rectangular supports I associate with earlier tubes?
I have seen identical tubes like this marked as ‘Chatham Electronics 5998’ ‘Western Electric 5998/421A’ and ‘Western Electric 421A’ and the internals are the same. And now ‘Chatham Electronics 2399’ with the code No 3002399, which I’m thinking should have the date code in it? Then there is also the number 743, which I take as week 43, 1957?

I am guessing we will never fully understand the why’s and wherefore’s of what manufacturer‘s got up to with markings back then. But any ideas on the pedigree of this tube? Thanks

 

[JKDJedi]

Hello there all,

Just what do I have here? Clear top, bottom D Getters and rectangular top mica supports. The rectangular supports I associate with earlier tubes?
I have seen identical tubes like this marked as ‘Chatham Electronics 5998’ ‘Western Electric 5998/421A’ and ‘Western Electric 421A’ and the internals are the same. And now ‘Chatham Electronics 2399’ with the code No 3002399, which I’m thinking should have the date code in it? Then there is also the number 743, which I take as week 43, 1957?

I am guessing we will never fully understand the why’s and wherefore’s of what manufacturer‘s got up to with markings back then. But any ideas on the pedigree of this tube? Thanks

interesting, I'd have to check into this one.Looks almost carbon copy like the Chatham 5998.