Hello colleagues,
What is your opinion on the (new) rf Tungsrams with getter like spots on the side?
How could they appear there by a manufacturing process? I think this producer is the only one to have this.
The image is not mine, is just for example.
What is your opinion on the (new) rf Tungsrams with getter like spots on the side?
How could they appear there by a manufacturing process? I think this producer is the only one to have this.
The image is not mine, is just for example.
After flashing getter condensation takes place on the coolest spot(s).
This is normally the dome section.
But if they use external holders / clamps / fixtures or whatever which keep these spots cooler than the rest of the glass tube some of the vapor can condensate there.
This is normally the dome section.
But if they use external holders / clamps / fixtures or whatever which keep these spots cooler than the rest of the glass tube some of the vapor can condensate there.
The EF86 is not an RF tube, its a screened low-noise audio preamp. The outer metal electrode is an internal screen, which is why its so large - so its a somewhat non-standard tube.
This isn't the usual barium getter which condenses on the glass close to the dish.
I had some EL84s that had these 'side flashes'.
One cracked, turning the top getter white instantly.
The flashes on the sides (which are in line with the holes of the anode) remained silver.
I had some EL84s that had these 'side flashes'.
One cracked, turning the top getter white instantly.
The flashes on the sides (which are in line with the holes of the anode) remained silver.
I have noticed these dark (when the process begins) or silvery patches on some heavily used tubes.
It always occurs in front of an aperture of the anode (or shielding), meaning it is probably some kind of metal sputtering or evaporation originating from the inside, most likely the cathode since it is the hottest spot in the tube.
I have no idea about the exact mechanism leading to that
It always occurs in front of an aperture of the anode (or shielding), meaning it is probably some kind of metal sputtering or evaporation originating from the inside, most likely the cathode since it is the hottest spot in the tube.
I have no idea about the exact mechanism leading to that
The same sport I have seen also on EBF80 tube which is rf, and I think on EF80 also
Hello colleagues,
What is your opinion on the (new) rf Tungsrams with getter like spots on the side?
How could they appear there by a manufacturing process? I think this producer is the only one to have this.
The image is not mine, is just for example.
i think this has many hours...
this is the problem, some people sayt they are new tubes, some they are used tubes. I am young, did not find out first hand in the 70s how is it, so this is why I am asking for wiser colleagues to share a little experience and memories
This could be an interesting explanation. Maybe other producers used tube holders that do not conduct heat (like if they had a cloth on them), and Tungsram used tube holders that conduct heat (like bare metal)
It is quite often on EL84 as was written. This "spots" can be find near holes in anode plate. This "spots" is connected with electrons, which fly over anode. I see this spots also on EL34, which run on quite high Ua.