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Tube myths Joint Army Navy vs Non Joint Army Navy

Joint Army Navy tubes, commonly referred to as JAN tubes, were tubes produced for the military. Tubes meant for the military, had to meet certain specs, as outlined, in the contracts, each manufacturer, had with the military. Though some contracts, called for a specially produced tube(RCA 5692, for instance), the vast majority of them, called for the same specs, as the industries, who tubes were mainly produced for, had. Consumer use, of tubes for audio, was small in comparison. The reason most think JAN tubes, are "better" tubes, is based on the myth, that they are different tubes. If the specs on a tube, say 6922 for example, were the same, for the Navy, as they were for , say, Hewlett Packard, then both tubes, were ran off the same lines(at different times, as orders dictated), with the same tooling, and same personnel. They are essentially, the same tubes. Most factories, ran a certain number of tubes, and then labelled them, as the orders, dictated. So a tube labelled H/P, was the same as a tube labelled Beckman. So you tell me, "which tube is better?"
fletchj
clueless
763 posts
 
said above by Hiwaves>>> "The owner had JAN tubes recently installed. The amps sounded OK, but when i replaced the tubes with Amperex tubes, the amps sound incredible, they just SING !!!
So much for the "sound quality" of JAN tubes."

I don't know what the sound quality of JAN tubes is, or if there is one such thing, but I do not agree that you can reach that conclusion from listening to one set of tubes in one circuit.

Sincerely
I remain,
jeffloistarca
1,004 posts
 
If tubes are anything like semiconductors (which I have 20 years experience with) the "differences" have to do with testing and traceability. Military semiconductors come off the same line as the standard devices do, but are subjected to a specified barrage of tests. Commonly referred to as "shake and bake" the military testing weeds out devices that may fail early on. The other significant difference is the paperwork that follows military devices through the factory and test floor, keeping a log of the measured specs as the part goes through the cycle. The parts that pass the military testing are sold under different part numbers and sell for a considerable mark up, anywhere from 10x to 40x the standard device pricing. Just to make things more confusing there are several levels of military screening: 883C, JAN 38510, and Level S (space level, for aircraft and space applications).
Bottom line is they come from the same production line as the chip sitting in your coffeemaker but are tested to insure longevity and consistent quality. Is it worth the premium? They are more rugged so they will last longer, other than that, no.
sugarbrie
3,854 posts
 
I honestly have never thought that certain tubes sounded better than others, solely because they were the military versions. There are just some types of tubes where the military versions just happen to sound the better. Others do not.

I was never aware of there even being a myth that the military tubes were automatically better. Makes me feel like some folks went for a sales pitch from someone selling those tubes.

I've always know those Amperex tubes were one of the best of those types. I never thought to considered whether they were military or not. It really did/does not matter to me.

The military tubes are just more durable. This is true of all things, even the military vs consumer model of the Hummer vehicle.
gs5556
1,218 posts
 
I don't know why or where this "myth" originated, but there are instances where, at least from my experience, the military version of a tube far outclassed the civilian variant: the Sylvania 6SN7 JAN CHS VT-231 and the RCA JAN 2A3 grey plates.

From what I understand, JAN tubes are manufactured to a military specification - not necessarily for the military. One of the most important parameters these tubes must meet is resistance to failure in high vibration environments and manufacture to tighter tolerances. For an audio application, this could mean a less microphonic tube. Not only that, but the mil-spec also dictated how they're packaged, shipped and stored - which means that the tubes found today probably had a better chance of surviving long term storage. Are they all better? Can't really make that blanket statement - because many of the commercial RCA/Sylvania/Ken-Rad/Philco/National tubes already met Mil-specs. But some specific variants ARE a different tube.
nameci
53 posts
 
I had some experience with 6dj8 family tubes: Amperex(Holland made), Siemens(German made), Philips(US made), and Sylvania(US made).
From my experience, on Amperex and Siemens, 6dj8 sounds the best, more air and warmth as well as frequency extension, compared to 6922 and 7308 version of same makers. 7308 sound the worst, bright, tinny, little harsh. And 6922 being in between 6dj8 and 7308. Funny thing is that 7308 is supposed to be the best in specification and 6922 is spec'ed for military use with long life compared to 6dj8. I guess best spec don't always yield best sound. On Amperex and Siemens, you can identify 6dj8 from 6922/7308 from their construction and date code.

One the other hand, Sylvania and Philips, both JAN 6922 and normal 6dj8 sound almost same if not same. Would it because they were all produced in same line but different label???
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