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-   -   Baking Tubes Procedure - Help... (http://www.diyaudio.com/forums/tubes-valves/231203-baking-tubes-procedure-help.html)

FullRangeMan 2nd March 2013 09:38 PM

Baking Tubes Procedure - Help...
 
Hallo all,
I hear about baking NOS tubes in a electric owen before use, but I was unable to find a topic in this site and abroad.
The tubes for baking are 6N1P, 6N6P, 6C33, GM70, they are all NOS, never used from the 1980s.
Any info are welcome, mainly on time and temperature etc...
Thanks

JonSnell Electronic 2nd March 2013 09:40 PM

Why would anyone wish to do this and what do you hope to achieve out of it apart from burnt fingers and possible permanent damage to the valves!

TheGimp 2nd March 2013 09:44 PM

Put the tubes in the oven with it cold.

Set oven for 175C and turn it on.

Let it run for 3 hours, turn it off and let it cool before opening the door.

This discolors Bakelite bases on octal tubes.

I believe Morgan Jones is credited with coming up with this procedure.

It is supposed to help activate the getter and remove residual gas in the tube.

I have experienced fewer problems with NOS tubes since I started doing this. Maybe it works, maybe it is just coincidence.

overtheairbroadcast 2nd March 2013 09:58 PM

Being as closed minded and ignorant as I am, I can not see what this would achieve even with the premise of activating the getter by heating it to get rid of residual gases.

At 175 C for three hours is more like cooking an unstuffed turkey, but wouldn't that already be surpassed by just turning on your amp and powering up the tube and heaters and playing music through it for a good while? The barium getter would be right hot and more than ready to get every molecule of gas at running temp. All of this without risking damage to the base or envelope (mostly by being overly eager and playing hot potato with an 805 or a 12AX7).

FullRangeMan 2nd March 2013 09:59 PM

Quote:

Originally Posted by TheGimp (Post 3393045)
Put the tubes in the oven with it cold.

Set oven for 175C and turn it on.

Let it run for 3 hours, turn it off and let it cool before opening the door.

This discolors Bakelite bases on octal tubes.

I believe Morgan Jones is credited with coming up with this procedure.

It is supposed to help activate the getter and remove residual gas in the tube.

I have experienced fewer problems with NOS tubes since I started doing this. Maybe it works, maybe it is just coincidence.

Thanks Bro, I appreciated it.
I just read someone do it with 130șC for 3 hours;
Maybe I would start it with 100șC for 3 hours with the small tubes, and next day up to 120șC, unless best suggestion...

JonSnell Electronic 2nd March 2013 10:03 PM

Quote:

Originally Posted by TheGimp (Post 3393045)
Put the tubes in the oven with it cold.

Set oven for 175C and turn it on.

Let it run for 3 hours, turn it off and let it cool before opening the door.

This discolors Bakelite bases on octal tubes.

I believe Morgan Jones is credited with coming up with this procedure.

It is supposed to help activate the getter and remove residual gas in the tube.


I have experienced fewer problems with NOS tubes since I started doing this. Maybe it works, maybe it is just coincidence.

How can one remove "Residual Gas" from a vacuum?
The heaters run at excess of 500 degrees Celcius, what is a domestic oven going to acheive?

What a load of rubbish!

TheGimp 2nd March 2013 10:10 PM

If a tube develops a leak the getter (flash) will turn white even at room temperature. Thus, the getter is still active. It works long after it is flashed onto the inside glass.

Since reaction with residual gas is temperature dependent as most reactions are, heating the tube will accelerate this action.

The procedure is based on sound principals.

FullRangeMan 2nd March 2013 10:12 PM

Quote:

Originally Posted by Harleyjon (Post 3393085)
How can one remove "Residual Gas" from a vacuum?
The heaters run at excess of 500 degrees Celcius, what is a domestic oven going to acheive?

What a load of rubbish!

The getter is supposed to do it if it is hot.
After 6 month or so the getter goes to sleep and need to be reactivated before usage.

I do not like to use my amp as test pilot for NIB NOS tubes made in overseas about 30 years ago.
The tubes need to be heated before receive HV in a amp.

JonSnell Electronic 2nd March 2013 10:14 PM

Not convinced as this defies science and as everyone knows, electron flow and the way they flow is scientific knowledge, not an old wifes tale. There is, by default, no gas in a vacuum.

TheGimp 2nd March 2013 10:17 PM

The "vacuum" in vacuum tubes is actually a partial pressure, albeit a very low partial pressure around .0001 torr iirc. There is no such thing as an absolute vacuum unless it happens at Absolute Zero", which room temperature is not.


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