The Reference 6SN7 Thread

[LoryWiv]

These work great and you can store the tubes upright

What is the advantage to upright storage?

 

[LobalWarming]

What is the advantage to upright storage?

Allegedly it's to keep the weak plates and filaments from sagging due to gravity and age. I know what that's like.

However, millions and millions of tubes have been stored horizontally for decades and decades without harm. And many some of those have gone on to lead a glamorous life as precious museum-quality holy grail artifacts.

 

[whirlwind]

What is the advantage to upright storage?

As already mentioned, some would say the filaments may sag over time due to gravity.

 

[Isaacc7]

As already mentioned, some would say the filaments may sag over time due to gravity.

I doubt any of the tubes we are discussing are in danger of sagging filaments. Very early tubes had longer and more delicate directly heated cathodes. WE says that if you mount a 300b horizontally you have to do it in a specific orientation.

https://frank.pocnet.net/sheets/084/3/300B.pdf

They don’t say you shouldn’t mount it horizontally just that you have to be careful. A sagging filament could potentially touch another element. My assumption is that once set upright, any sag would disappear. 6sn7, and I assume other small twin triode tubes in contrast say they can be mounted in any orientation.

http://www.triodeel.com/6sn7_p1.gif

So many of the input tubes we use were designed for use in cars, airplanes, etc. and so are quite robust. Has anyone ever seen guidance from the manufacturers about orientation of tubes during storage? I’ve never heard of it but I haven’t been looking for it either.

 

[whirlwind]

I can't really imagine any 6SN7 tubes or any smaller tubes being effected by filament sag.

I would think it would be a non issue with most all tubes.

 

[sam6550a]

I doubt any of the tubes we are discussing are in danger of sagging filaments. Very early tubes had longer and more delicate directly heated cathodes. WE says that if you mount a 300b horizontally you have to do it in a specific orientation.

https://frank.pocnet.net/sheets/084/3/300B.pdf

They don’t say you shouldn’t mount it horizontally just that you have to be careful. A sagging filament could potentially touch another element. My assumption is that once set upright, any sag would disappear. 6sn7, and I assume other small twin triode tubes in contrast say they can be mounted in any orientation.

http://www.triodeel.com/6sn7_p1.gif

So many of the input tubes we use were designed for use in cars, airplanes, etc. and so are quite robust. Has anyone ever seen guidance from the manufacturers about orientation of tubes during storage? I’ve never heard of it but I haven’t been looking for it either.

Filament sag happens in some [usually large] tubes that have directly heated cathodes, i. e., the filament is the cathode. Most audio tubes [except the large power triodes] employ indirectly heated cathodes, where the heater is enclosed within a tubular cathode, so filament droop cannot occur.

 

[LoryWiv]

Allegedly it's to keep the weak plates and filaments from sagging due to gravity and age. I know what that's like.

However, millions and millions of tubes have been stored horizontally for decades and decades without harm. And many some of those have gone on to lead a glamorous life as precious museum-quality holy grail artifacts.

Ah, thank you for explaining the gravity of the situation!

 

[LobalWarming]

Ah, thank you for explaining the gravity of the situation!

Happy to field any questions in the low orbit of my expertise.

 

[paradoxper]

I can't really imagine any 6SN7 tubes or any smaller tubes being effected by filament sag.

I would think it would be a non issue with most all tubes.

It's a definitive problem with older bigger tubes. the 45 and especially the mesh types are very susceptible due to very minimal support.

 

[whirlwind]

It's a definitive problem with older bigger tubes. the 45 and especially the mesh types are very susceptible due to very minimal support.

Correct, the older bigger tubes are more suspect.

 

[LobalWarming]

It's a definitive problem with older bigger tubes. the 45 and especially the mesh types are very susceptible due to very minimal support.

Fortunately, there's not many large mesh directly heated 6SN7s around anymore.

 

[Mr Trev]

Fortunately, there's not many large mesh directly heated 6SN7s around anymore.

and could you imagine what they'd cost if there were

 

[jonathan c]

I can't really imagine any 6SN7 tubes or any smaller tubes being effected by filament sag.

That would be a certainty if there were “Valvagra” !!….

 

[sam6550a]

and could you imagine what they'd cost if there were

Especially since they are as extant as unicorns.

 

[LoryWiv]

That would be a certainty if there were “Valvagra” !!….

Well if the tube was already upright it wouldn't need Valvagra, would it?