A decent NOS Upscale Audio tube find?

BassKulcha

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I found these Upscale Audio marked tubes today for about a buck a piece. Not all of the notation on the boxes (or the boxes themselves) matched the enclosed tube, so it's unclear if the measurements reflect each of them. (Plus, like a dummy, I took them out and ended up trying to match them up, which just made it more confusing...)

From what I can tell, here's what I have:

8 military-branded Mullard CV4024 / 12AT7
2 military-branded Mullard CV4004 / 12AX7
3 Wurlitzer/GE-branded 12AX7
3 "VTL" EI- branded 12AX7WA (couldn't find much info about this, but it looks like a modern Russian tube?)
1 GE-branded JAN 5670
1 Electro-Harmonix-branded 12AU7A
1 JJ Electronics-branded ECC81/12AT7

Seems the military-branded 12AT7s and the military-branded 12AX7s come from Upscale Audio (those 12AX7s are pricey!), but not sure about anything else. I don't have an ability to test them (or match them), but they "look" good and the getter seems nice and shiny (—is that a way to identify strong tubes?), so I'm hoping these are useable...

If anyone has any info that would be much appreciated!

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If it says "cryogenically treated" I'll bet they went for big dollars. How do you cryo a tube anyway? Wouldn't it be prone to imploding? Dunno.
 
If it says "cryogenically treated" I'll bet they went for big dollars. How do you cryo a tube anyway? Wouldn't it be prone to imploding? Dunno.
Just look for a tube seller who uses cryo treatment, and you can get the poop on that . they love to brag about the wonders of such. I personally think cryogenic treatment does work, but the difference is very subtle. and outside of a laboratory probably undetectable. Although some of the benefit might be longevity.
I found these Upscale Audio marked tubes today for about a buck a piece. Not all of the notation on the boxes (or the boxes themselves) matched the enclosed tube, so it's unclear if the measurements reflect each of them. (Plus, like a dummy, I took them out and ended up trying to match them up, which just made it more confusing...)

From what I can tell, here's what I have:

8 military-branded Mullard CV4024 / 12AT7
2 military-branded Mullard CV4004 / 12AX7
3 Wurlitzer/GE-branded 12AX7
3 "VTL" EI- branded 12AX7WA (couldn't find much info about this, but it looks like a modern Russian tube?)
1 GE-branded JAN 5670
1 Electro-Harmonix-branded 12AU7A
1 JJ Electronics-branded ECC81/12AT7

Seems the military-branded 12AT7s and the military-branded 12AX7s come from Upscale Audio (those 12AX7s are pricey!), but not sure about anything else. I don't have an ability to test them (or match them), but they "look" good and the getter seems nice and shiny (—is that a way to identify strong tubes?), so I'm hoping these are useable...
CV4024 is a military grade 12at7. Yours looks like they maybe Mullards. They are an upgrade over the standard at7. They are still available NOS from tube mongers in the UK.
CV4004, is a little trickier since they were quite a few ecc83 designated as cv4004. It is one of those numbers that were remarked onto normal ecc83 when the market got greedier. IIRC the original were Brimar made and have a distinctive construction and also the "box plate" Mullard.
 
CV4004, is a little trickier since they were quite a few ecc83 designated as cv4004. It is one of those numbers that were remarked onto normal ecc83 when the market got greedier. IIRC the original were Brimar made and have a distinctive construction and also the "box plate" Mullard.

Thanks primosounds. The CV4004/12AX7s do appear to have the box plate (seem like the same Mullards described in the Upscale Audio video linked above—). I'm still wrapping my head around tubes, so it's bit unclear to me—

Anyone know anything about the VTL 12AX7WAs?
 
All I know about 12AX7 tubes is that they made my Foreplay sound sweeeeeet. And they also made the preamp work well. :) :)
 
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I think its interesting. I'm asking these guys what they charge to cryo a gun barrel. http://www.300below.com
I experimented at work once. We used to keep liquid nitrogen in tanks and i put some 12ax7 into the tank in slow stages. But it was not as controlled as the way they do it at a controlled cryo place. The results were it made the tube microphonic. Like i said it was not the proper way to do it , so, i don't recommend you diy, cryo treat your tubes.
 
I experimented at work once. We used to keep liquid nitrogen in tanks and i put some 12ax7 into the tank in slow stages. But it was not as controlled as the way they do it at a controlled cryo place. The results were it made the tube microphonic. Like i said it was not the proper way to do it , so, i don't recommend you diy, cryo treat your tubes.

Yeah I don't think that's a good idea either. However, it's interesting that it had an effect. Bad or good, if you got something to happen that means it affects the tube. So maybe done a certain way it will have a good effect instead of a bad one.
 
If it says "cryogenically treated" I'll bet they went for big dollars. How do you cryo a tube anyway? Wouldn't it be prone to imploding? Dunno.
Cryo tubes are very slowly brought down from room temp. to -300 deg. F. over a 24 hr. period. Then left to "soak" for 24 hrs. Finally, brought back to room temp. over yet another 24hrs. This started as a military tempering procedure which flattens out any wrinkles in the tube plates. Note that they never touch the liquid or vapor directly either. Whether is makes a sound difference, I don't know.
 
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