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
http://www.diyaudio.com/forums/tubes-valves/211145-another-tube-fact-fallacy.html#post2992795
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.
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.
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
http://www.diyaudio.com/forums/tubes-valves/211145-another-tube-fact-fallacy.html#post2992795
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
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
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
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.
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.
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.
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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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
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
Cathode absorbs gases as well as a getter, but it poisons cathodes lowering their emission. Cathode stripping is another thing, it happens when anode-cathode current heats up hottest spots of cathode increasing their temperature even further. It happens when very powerful transmitting tubes have high anode voltage present before cathodes are heated up, especially in transmitters where negative bias is obtained by rectification of oscillations on the control grid. I.e. requirements to avoid stripping and poisoning are contradictory. In tubes that we use for audio cathode stripping does not happen, but cathode poisoning is the real problem.
Activating getter in an oven is better way to prepare NOS tubes for service.
Well cleared Mr Wavebourn, My friend Popilin (Juan Esteban) had a little idiomatic mistake but the concept is well knew because I talked many times with him about this.
Cold cathode→striping. We can solve it delaying the +B until the cathodes became properly hot.
Hot cathode without polarization→Poisoned We can solve it in standby dropping the filament voltage. We can de poisoned them applying much voltage to the filaments and making pulses of +B (no warranties)
The clue for absorb gas is getter. There are valves with graphite anodes that continuing absorbing gases with the time.
The question is to be or no to be preconditioned valves?
Do you advocate such measure?
Cold cathode→striping. We can solve it delaying the +B until the cathodes became properly hot.
Hot cathode without polarization→Poisoned We can solve it in standby dropping the filament voltage. We can de poisoned them applying much voltage to the filaments and making pulses of +B (no warranties)
The clue for absorb gas is getter. There are valves with graphite anodes that continuing absorbing gases with the time.
The question is to be or no to be preconditioned valves?
Do you advocate such measure?
From Maxwell's equations
∇ . D = 4 π ρ
∇ . B = 0
∇ x E + (1/c) ∂ B / ∂ t = 0
∇ x H – (1/c) ∂ D / ∂ t = (4 π/c) J
The magnetic field B due to a current i (DC) is given by
B = µ i(DC) / (2 π r)
This in turn produces a magnetization
B = H + 4 π M
Nickel alloy is ferromagnetic, so at least the anode can be magnetized.
This magnetization, produces a deflection of the electrons in its path.
In a CRT the current I (DC) is very small, in the order of 1 µA, but the effect of anode's magnetization is very noticeable and annoying.
Obviously, for higher currents, such as in an output pentode, the magnetization is greater.
How does this affect the sound?
I answer you in four words
I have no idea
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Gu-50 tubes in my amps sing nice without any demagnetization. They have nickel anodes. You can bake them by heating up anodes to red color. No problems after that. Bake anodes of KT-88 such a way, and they are dead.
The curie temperature said that: Lost all the magnetic properties rising to some point.
When Mr Wavebourn became hot his plates rises until Tº Curie.
In the past with a friend valve lover we torched with flame directely to the glass envelope of the Valves.
(Cause I love my wife I did the same her but her getter never activate de gassing herself)
Another point Mr Popilin. You kill me hard and deep with all this mathematics.
But one observation, IMHO, the Anode surround all the system (screens, grids and cathode) and the electronics cloud goes until it. If any stupid magnetic fields became present in the inner anode structure, that magnetic field going to surround the above mentioned structures, "Ergo" this magnetic field does not make anything annoying to the electronic clouds.
When Mr Wavebourn became hot his plates rises until Tº Curie.
In the past with a friend valve lover we torched with flame directely to the glass envelope of the Valves.
(Cause I love my wife I did the same her but her getter never activate de gassing herself)
Another point Mr Popilin. You kill me hard and deep with all this mathematics.
But one observation, IMHO, the Anode surround all the system (screens, grids and cathode) and the electronics cloud goes until it. If any stupid magnetic fields became present in the inner anode structure, that magnetic field going to surround the above mentioned structures, "Ergo" this magnetic field does not make anything annoying to the electronic clouds.
The vacuum in a valve is not perfect, so there are gas molecules randomly floating between the anode and cathode.
If an electron should be accelerated towards the anode from the cathode, there is always a chance that it will collide with a gas molecule and have sufficient energy to remove an electron from that molecule, rendering it positively charged and attracted to a lower potential such as the cathode.
In metals, at normal temperature, the conduction band is essentially filled of electrons only up to the Fermi energy EF, to extract an electron from the metal is therefore necessary to give a starting energy ei, but at high temperatures the occupation of electronic states extends above EF. If the temperature is high enough, some electrons reach energies greater than EF + ei, and escape from the metal.
If the temperature increases further, as suggested in this thread, the Fermi energy level is widely exceeded and electrons have enough energy to collide with a gas molecule and so on.
Forgive my Tarzan-English, I interpreted the above phenomenon as Cathode Stripping.