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Old 10th July 2012, 08:04 PM   #541
BUIZERD is offline BUIZERD  Netherlands
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Dear DADY,

I think it is best for you to read all 54 pages of this topic!!!
Did this myself a lot of times, it surely clear's things for you.
If you read carefuly, you will understand what it's all about.
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Old 10th July 2012, 08:10 PM   #542
popilin is offline popilin  Argentina
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Quote:
Originally Posted by dady View Post
You Mr Buizerd have the mother bench and can establish the standard parameters.
Respect to pre-conditioning what is this and which is the object to do.

Does Improve the emission? Does de poison the cathode? Does Is necessary DC or AC ? What amount of Its? Does Prolonged the live?

Best Regards for all and good sumer time. Here on Menorca the season come with the best. My family is enjoying every day.
Como no te dan bola, encontré esto
Webiando found this

AE1S Amateur Radio Blog: "Gettering" GU74b / 4CX800A

All that you need is heat, so AC or DC is irrelevant.
Do not exaggerate with the times, it is said there, that valves "age"
Another way would be heated in an oven, but I can not give any recipe in this regard, I have read here on the forum

another tube fact or fallacy

However, if over time by some external/internal field, the valve is magnetized, it is best to demagnetize it with an external solenoid, of course powered by AC.
Let me know if you need and pass the data, works wonderfully in CRTs.
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Old 10th July 2012, 09:41 PM   #543
dady is offline dady  Argentina
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Quote:
Originally Posted by BUIZERD View Post
Dear DADY,

I think it is best for you to read all 54 pages of this topic!!!
Did this myself a lot of times, it surely clear's things for you.
If you read carefuly, you will understand what it's all about.
I think you have to read again all the topic. AND BEEN MORE VOLUNTEER AT THE TIME OF HELP TO EACH OTHER. IF YOU START TO HELP THE OTHERS WITHOUT TRIBULATIONS AND SPECULATION.
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Old 10th July 2012, 09:52 PM   #544
dady is offline dady  Argentina
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Quote:
Originally Posted by popilin View Post
Como no te dan bola, encontré esto
Webiando found this

AE1S Amateur Radio Blog: "Gettering" GU74b / 4CX800A

All that you need is heat, so AC or DC is irrelevant.
Do not exaggerate with the times, it is said there, that valves "age"
Another way would be heated in an oven, but I can not give any recipe in this regard, I have read here on the forum

another tube fact or fallacy

However, if over time by some external/internal field, the valve is magnetized, it is best to demagnetize it with an external solenoid, of course powered by AC.
Let me know if you need and pass the data, works wonderfully in CRTs.
This is a real form of help the partners.
Maybe couse you are a partner.
Thanks Popilin for your clarity and understanding
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Old 10th July 2012, 10:00 PM   #545
BUIZERD is offline BUIZERD  Netherlands
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Well hello Dady,

It is not necessary to be mad at me, I just want to help.
But there are a lot of people here on this forum who can explain things much better than I can.
That's why I wrote to read this topic to again.
So if you take the trouble to read everything again, you will naturally find the answers you seek.

NO OFFENCE
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Old 10th July 2012, 10:29 PM   #546
BUIZERD is offline BUIZERD  Netherlands
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Dady, Especially for you,

This is what one of the other members wrote in the past,

Awakening(precondition) process is for long standing unused tubes the very good start point for sure.(on the each 6c33c-b tube is engraved production year,just near on the right side next the factory logo(Ulyanovsk),74 mean year 1974 or 82 mean 1982..., so looking in average years this tubes is the real NOS ! and they need careful kathodes precondition for normal operation.
So 72 hours of kathode precondition per each tube, done exactly in that way which you already doing,with all pins tied together on the one side of the filament.
Be sure that this `break in` process is related with kathodes precondition but not to much with internal tube gas,this tubes are very good sealed so the tube vacum loses is very rare,except if some glass crack exist usually near to the tube pins, but this is very rare effect indeed for Russian high MIL production norm.
There is something else related to 6c33c-b/6h13c tube precondition:Since the internal tube metal structure is produced & formed from magnetic materials,precondition of this tubes with 72 hours filaments turned on mean internal demagnetization of the tubes too,with relative high standing temperature radiated from glowing kathode to surrounding metal structure of this electron tubes,actually this demagnetization process can not be done in five minutes but in 72 hours is done for sure.
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Old 10th July 2012, 11:34 PM   #547
PET-240 is offline PET-240  Australia
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Just to understand completely the precondition you fellas are discussing. The plates and grids are tied to the cathodes by the tube base pins, so all internals apart from the heaters are interconnected, no voltage applied to anything but the heaters.
That make sense?
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Old 11th July 2012, 04:34 AM   #548
popilin is offline popilin  Argentina
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Quote:
Originally Posted by PET-240 View Post
Just to understand completely the precondition you fellas are discussing. The plates and grids are tied to the cathodes by the tube base pins, so all internals apart from the heaters are interconnected, no voltage applied to anything but the heaters.
That make sense?
You're right, it makes no sense.
Even worse, working a valve with maximum cathode temperature, without a potential difference to accelerate the electrons produced by thermionic effect, is the best way to produce "cathode stripping" and "cathode poisoning"

As I said before, it does make sense to heat the valve to activate the getter.
But not at the cost of damaging the valve.
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Old 11th July 2012, 05:19 AM   #549
popilin is offline popilin  Argentina
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Quote:
Originally Posted by BUIZERD View Post
Since the internal tube metal structure is produced & formed from magnetic materials,precondition of this tubes with 72 hours filaments turned on mean internal demagnetization of the tubes too,with relative high standing temperature radiated from glowing kathode to surrounding metal structure of this electron tubes,actually this demagnetization process can not be done in five minutes but in 72 hours is done for sure.
If the heater is powered by DC, for normal values of current, it can be demonstrated that the constant magnetic field due to DC current is not enough to magnetize the internal structure of the valve.

If the heater is powered by AC, for normal values of heater voltage, it can be demonstrated that the magnetic field due to AC voltage is not enough to demagnetize the internal structure of the valve.

If you intend to reach the Curie temperature, at most you can demagnetize the cathode, I can not assure the same for the grid and the anode.

Anyway, it's a naive way to demagnetize a valve.AFAIK
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Last edited by popilin; 11th July 2012 at 05:22 AM.
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Old 11th July 2012, 09:16 AM   #550
dady is offline dady  Argentina
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I think that the magnetization of the internals structures of the valve is so little if you consider the magnetization rate of the alloy that is not predominant ferrous maybe little nickel, by the way also the current of electrons between the electrodes are so important taking on mind the size of the electrodes, if you compare with a CRT. In CRT you generate a thin beam that across a big distance and you deflectionate with a powerful magnetic field. The situation on Vacuum tubes is minimum and depreciable.
The topic is more related to OTL than the measures for rejuvenation of old tubes. Respect to this, I read many articles but many, and each time I see one of them I putt all my attention because one of the problems for tubes, they age and became old like everything in this world. I did on the past some of the actions describes in that part of this topic, Rising the filamentary voltage, rising the current, putting magnetos near of tubes, putting AC coils and putting heat without connection. The more reliable in this was the de poisoning of the cathode in old tubes. If somebody heat the filaments without biasing the rest of electrodes the cathodes became poisoned.
Long time ago I experimented with 7 units of NOS UX2A3 I got once and they were stored for 40 years. They were never used but they plate current was so poor. They improve until rise the same like new but after rise the filament voltage in peaks but with the polarization of all the elements. They were DHT and the problem of indirect heated cathodes I don't know if is the same.
I ask to the more experimented people in this forum, like ATMA that maybe he had or not this problem specially because he all the time is getting big quantities.

But magnetization of the electrodes, While nobody convince with heavy and reliable evidence I consider we are looking for a solution without a real problem.

Buizers your machine looks fine and profesional. If you wanna help please cite the number of post or the link. I am so interested in find more solutions also in learn about electronics applied to DIYaudio specially tubes and the challenge of make "that real thing" in my living room but taking as target to the music. I am not MAD. Is a theatric stage.
Beste regards
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