Dr ZEE
Anti-Pro Circles Insider
now test on tube tester.
Note: "G" (grid) set to "2" and "K" (cathode) is set to 3 - test between pins 2 and 3 - indicates "SHORT" - indicator lamp glows.
Actually the way it happens is this. When you insert the tube into the socket - at first there's no short indication , but as the heater warms up - the neon lamp indicator starts blinking and then it gets brighter and then glows continiously.
Note: "G" (grid) set to "2" and "K" (cathode) is set to 3 - test between pins 2 and 3 - indicates "SHORT" - indicator lamp glows.
Actually the way it happens is this. When you insert the tube into the socket - at first there's no short indication , but as the heater warms up - the neon lamp indicator starts blinking and then it gets brighter and then glows continiously.
Attachments
Dr ZEE
Anti-Pro Circles Insider
Dr ZEE
Anti-Pro Circles Insider
As far as "emission" goes - that is another story.
Basically - bad emission - bad tube, good emission - good tube. Right? Well, maybe so, but I am not sure about it.
In general, the problem is that if you see a nicely glowing tube it does not mean that it is a good tube. Also a tube that is tested "BAD" for emission is not necessarily is useless or flat out bad. I have for example a tube that I've tested "BAD" for emission. A nice looking british 7025 tube. So, I've said: "Sh*t! Arghhh - to damn bad." SAnd then I've tried it in one of my guitar amps in preamp section, and it actually worked just fine. Maybe not so good for a lab test or for some application, but I could rockin'roll with it pretty damn well.
I've read that "good emission" does not mean that the tube is good, but I have never had such experience, or maybe it's because I just do not have high demands on a tube performance.
Also, I think it would be worthy to mention here. I think, when dealing with any old tube piece of gear - the tubes most likely are fine in there and if it does not work right, then the problems are most likely somewhere else. I maybe wrong on that one, though, but I have been successful in the past in scoring great tubes by purchasing old non-working DOA gear for cheap 
- that is the trick, well, sort of .
here's that tube, tested BAD, but it rocks - so go figure.
Basically - bad emission - bad tube, good emission - good tube. Right? Well, maybe so, but I am not sure about it.
In general, the problem is that if you see a nicely glowing tube it does not mean that it is a good tube. Also a tube that is tested "BAD" for emission is not necessarily is useless or flat out bad. I have for example a tube that I've tested "BAD" for emission. A nice looking british 7025 tube. So, I've said: "Sh*t! Arghhh - to damn bad." SAnd then I've tried it in one of my guitar amps in preamp section, and it actually worked just fine. Maybe not so good for a lab test or for some application, but I could rockin'roll with it pretty damn well.
I've read that "good emission" does not mean that the tube is good, but I have never had such experience, or maybe it's because I just do not have high demands on a tube performance.
Also, I think it would be worthy to mention here. I think, when dealing with any old tube piece of gear - the tubes most likely are fine in there and if it does not work right, then the problems are most likely somewhere else. I maybe wrong on that one, though, but I have been successful in the past in scoring great tubes by purchasing old non-working DOA gear for cheap
- that is the trick, well, sort of .here's that tube, tested BAD, but it rocks - so go figure.
Attachments
evm1024
New member
I gotta learn to spell
THat silver is called the "getter" and is typically a metal like barium. It is silver when on the glass and will quickly oxidize to a white color if the envelope leaks and lets oxygen in.
http://en.wikipedia.org/wiki/Getter
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Wil816 said:
THat silver is called the "getter" and is typically a metal like barium. It is silver when on the glass and will quickly oxidize to a white color if the envelope leaks and lets oxygen in.
http://en.wikipedia.org/wiki/Getter
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D
dementedchord
Psychotic State alumni ch
BTW... would you guy's do me a favor and learn the diff between a short and an open...
a short implys a lack of resistance.....
an open is total resistence....
and we know resistence is futile....
transistors generally short
resistors open
diodes short
caps short
inductors can do either but ultimately open
think of it a fuse which shorted would'nt be any protection at all....
a short implys a lack of resistance.....
an open is total resistence....
and we know resistence is futile....
transistors generally short
resistors open
diodes short
caps short
inductors can do either but ultimately open
think of it a fuse which shorted would'nt be any protection at all....
Dr ZEE
Anti-Pro Circles Insider
the favor is done.dementedchord said:would you guy's do me a favor and learn the diff between a short and an open
now, what are YOU going to do about it?dementedchord said:
rory
New member
Nope.