What kind of tubes do i have?

[Gary Diamond]

Hi, I'm new here, i dug out my 12AX7 and 12AX7A tubes and I'm

not sure what i really have on the 12aX7A s i want to sell them,

but here's the question, all the 12AX7As were covered with red

paint and they read half of what the blue ones do that are 12AX7s

some one in the 60s must have preselected them or they were colored so

there would be no mistaking the two types of tubes

they were used for sonobuoys for the Navy and made by SYLVANIA

I pulled these out of the trash when i worked for them in R&D for the new transistor models
Here is some pics




Gary

[Richard Ellis]

Not sure of the "A" variation. Yes it would seem they marked them so there would be no mix-up when sailors were servicing these buoys...it is sometimes difficult to see the other markings when servicing out in the field..a paint mark was a simple solution. I wouldn't like to smell the cooking paint as one of those are fired up.
There are so MANY 12AX7s' in circulation now....perhaps a Navy marked version MIGHT be of some sort of collector value, but I doubt it.
The supply of 12AX7s' is enough to keep us all happy for the next thirty years...given the projected lifetime of a 12AX7.

__________________________________________________ ______Rick.....

[Gary Diamond]

Originally Posted by Richard Ellis

Not sure of the "A" variation. Yes it would seem they marked them so there would be no mix-up when sailors were servicing these buoys...it is sometimes difficult to see the other markings when servicing out in the field..a paint mark was a simple solution. I wouldn't like to smell the cooking paint as one of those are fired up.
There are so MANY 12AX7s' in circulation now....perhaps a Navy marked version MIGHT be of some sort of collector value, but I doubt it.
The supply of 12AX7s' is enough to keep us all happy for the next thirty years...given the projected lifetime of a 12AX7.

__________________________________________________ ______Rick.....

Thanks for your input the navy guys never touched them they were sealed and only used once, we used to bring them back for study after a drop, it was cheaper to make a new one.
I ran them in a amp, and what ever the color stuff is it don't smell or cook i think it's made of the same stuff they stamp the tube with, the navy would never go for cheap stuff.

Have sold 24 of them last week, i don't expect to sell all of them to one person, but you never know.

I'm not sure were the best place is to run a ad, so it's trial and error
Gary

[Pano]

Put them in the Swap Meet section with a price.

Or list them on Audiogon.

[kevinkr]

Funny you mention sonobuoys, my dad was involved in a Navy test program in the late 1950s and I actually had one of them which is unfortunately now long lost.
(He managed a development program at Hazeltine which designed some of the sonobuoys the navy was testing at the time.)

I'm in need of a few 12AX7A for regulator service so would be interested in buying a few for nostalgia, etc..

Send me a private mail (PM) here on the forum with your asking price..

[Gary Diamond]

Originally Posted by kevinkr

Funny you mention sonobuoys, my dad was involved in a Navy test program in the late 1950s and I actually had one of them which is unfortunately now long lost.
(He managed a development program at Hazeltine which designed some of the sonobuoys the navy was testing at the time.)

I'm in need of a few 12AX7A for regulator service so would be interested in buying a few for nostalgia, etc..

Send me a private mail (PM) here on the forum with your asking price..

I do remember Hazeltine in the the sonobuoy business, i came into the company that was making them and we bought out a another company that was making them with tubes, maybe it was hazeltine, that was a long time ago, i would love to have the tube design on it. I still have a transistor RF board for the sonobouys

Please send me a PM with your phone number

Gary

[fdegrove]

Hi,

Not sure about what your question is but technically speaking the sole difference between a 12AX7 and the A version is that the latter has controlled heater start up.

I.e. no visible flaring of the heaters at cold switch on.

Cheers,