Tung-Sol 12ax7 bottle size bigger

HipKitty

Silver Supporting Member
I haven't seen this posted as of yet, however, has anyone else encountered the larger bottle size to the new production Tung-Sol 12ax7's yet?

I can say that I have and it blew me away. They are barely able to be squeezed into the typical Fender shield base....they will go, but they will scrape off the batch numbers screen printed on the bottles.

It turned out that my supplier was unaware of the situation so he checked it out himself. Found that there is a difference from older batches and emailed Mike Mathews.

Mike's response was that they had to go to the bigger bottle size in order to eliminate a production issue causing noise during the tube usage.

I'm curious as to who else has had the same encounter.
 
Meow do they sound compared to the svelte tung-sol bottle ?

Thanks
Groovey Records
Listening to Wes Mongomery with Strings
on Vintage Vinyl of Course
 

HipKitty

Silver Supporting Member
Meow do they sound compared to the svelte tung-sol bottle ?

Thanks
Groovey Records
Listening to Wes Mongomery with Strings
on Vintage Vinyl of Course
They sound like the early production Tung-Sols...definitely quieter than the last bunch that I received. No noticeable microphonics when maxxing the gain in our Mesa Mark IV.
 

Trout

Member
EH 12AY7's are an aweful fit also, Stands to reason I guess, they are both New Sensor products.

I have some Chinese 12AX7's labeled Fender with the same problem, No worries about them ever getting loose or falling out, IF you can get them in! lol
 

HCStraub

Member
I actually brought this up to Mike Mathews(owner of New Sensor/TungSol brand) at NAMM 2 weeks ago. He asked why I wasn't using them in my amps. I told him that they didn't fit in the shield bases. He claimed to have never heard of the issue but said he would look into it.
The first batch I got(30 tubes), the glass thickness was all over the board, some didn't fit at all, some were very tight. I eventually gave up and went back to JJ.
 

mc5nrg

Member
I pulled the 12ax7s from a mid-60s Knight Open reel I came upon. One of the tubes had a shield that for all intents and purposes might as well have been shrink-wrapped on the tube like a second skin. I did manage to pop the tube out and the Amperex bugle boy print remained intact.
 
Meow do they sound compared to the svelte tung-sol bottle ?
Hahah, I almost spit my coffee out reading this. Thanks for the morning laugh...I just saw that movie the other day.

Back on topic.

I'd like to try some of these new big bottle Tung-Sol 12AX7. Where can I pick some up? Or would some of you gents who aren't happy with the big bottle care to part with them?
 

2tones

Member
Apparently, Russian and Chinese manufacturers are not as fussy about the size of the glass envelope. This problem has existed for years. If you have a caliper handy, just measure the diameter of an old 9-pin NOS tube and compare it to a Sovtek, Electro-Harmonix, Groove Tubes, Etc.

Anyone with an older Swart AST should be very aware of this problem, as the preamp tubes fit through holes in the chassis. Some Russian and Chinese tubes just won't fit. They're too plump.

JJ's don't seem to suffer from this problem.

I'm assuming this thread refers to Russian made Tung-Sols - a "real" Tung-Sol should be the correct diameter.
 

HipKitty

Silver Supporting Member
Apparently, Russian and Chinese manufacturers are not as fussy about the size of the glass envelope. This problem has existed for years. If you have a caliper handy, just measure the diameter of an old 9-pin NOS tube and compare it to a Sovtek, Electro-Harmonix, Groove Tubes, Etc.

Anyone with an older Swart AST should be very aware of this problem, as the preamp tubes fit through holes in the chassis. Some Russian and Chinese tubes just won't fit. They're too plump.

JJ's don't seem to suffer from this problem.

I'm assuming this thread refers to Russian made Tung-Sols - a "real" Tung-Sol should be the correct diameter.
Yeah, the thread is about the NS (Russian) Tung-Sols.

I did go through everything in my stock and calipered them all. Yes, there are variances, but nothing this large...this includes my old stock GE's, RCA's, Ei's, JAN's (USA), and Amperex...and my newer stock TAD's (Chinese and Russian), GT's (Chinese and Russian), Mesa's (Chinese), JJ's, Fender's (Chinese and Russian), EH's (Russian), and the Sovteks WA's and WB's.

I'm going to take it from some of these posts, that the larger bottles have existed for years. Interesting.
 

jbird

Member
My buudy, trying to replace one of his 12AX7's in his Twin Reverb, ran into the same problem with a GT he got from GC.
 


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