I shipped a couple of EHKT88s. The receiver of the tubes said that he can see a small glass bead, about 1mm, free moving, inside the tube. He also said that the getter was still silver and there did not appear to be loss of vacuum. The tubes are part of a kit, so he has not powered them up yet.
Has anyone else ever seen this? Could it just be from the manufacturing process? Is it a problem?
Thanks,
Scott
Has anyone else ever seen this? Could it just be from the manufacturing process? Is it a problem?
Thanks,
Scott
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I've seen small glass extrusions from the manufacturing process brake off. In one of my rectifiers I have a 2cm piece of glass which broke off the anode connecting rod (top connection to internal plate). No harm comes to the tube but it obviously depends. Being a sphere I guess manufacturing debris and NOT piece of the tube. Hopefully it did not damage anything.
I am the receiver of the tube
I have attached a picture where it can be seen a small piece of glass in the bottom part of the tube, I think you can figure out the real size by comparing it to the base.
Best regards!
Completely harmless, nothing to worry about. It actually happened more on old stock stuff than on the new production.
I had exactly the same issue with a set of Electro Harmonix KT88's I bought a couple of years back - a small piece of glass about 2 or 3mm across inside the tube. Did not have any issues with that tube. I'm sure I could dig the tube up if you want a photo. Ironically, it was the tube WITHOUT the random glass bead out of that set that failed first....
Seems ok so far, but it looks like the glass bead is small enough to fit through the holes in the anode structure - where it might cause mechanical damage to the screen grid. So better be careful when moving the tube and check/watch where the debris is.
Luckily, glass is non-conductive, so there shouldn't be any problem with it.
Greetings,
Andreas
Luckily, glass is non-conductive, so there shouldn't be any problem with it.
Greetings,
Andreas
Thank you guys! Those comments greatly reassure me. I thought that it could be harmless but, due to my limited experienced with valves (that will be my first tube amp), I preferred to get a more fundamented opinion.
Thanks for all once again!
Best regards
Thanks for all once again!
Best regards
the real problem will be getting the glass out of your head!
(just to say...people are addicted to vacuum tubes! 🙂 )
(just to say...people are addicted to vacuum tubes! 🙂 )
Another reassuring reference point. I've got a noval tube with a chunk of glass running around loose inside. It's never given me any problem.
http://i69.photobucket.com/albums/i43/Ty_Bower/Tubes/P1100245.jpg
http://i69.photobucket.com/albums/i43/Ty_Bower/Tubes/P1100245.jpg
the piece missing in this picture
is a finger long and keeps rattling inside the tube..nothing happened yet.
is a finger long and keeps rattling inside the tube..nothing happened yet.
Another question related to an inexperienced user with valves. I got two of the KT88 valves and noticed that, if lightly finger tip beated, they somehow rattle. BUT one of them tend to rattle quite more than the other.
I suppose that this poses no problem at all, but would like some personal opinions/experencies from people that has been playing around with valves for a while. Do they use to rattle, does it vary from model to model, can it affect microphonics, etc...?? Just out of curiosity 🙂
I suppose that this poses no problem at all, but would like some personal opinions/experencies from people that has been playing around with valves for a while. Do they use to rattle, does it vary from model to model, can it affect microphonics, etc...?? Just out of curiosity 🙂
allthrough a short is Very unlikely . 😀
the only place you'd expect shorted valves would be in old radio's .
the only place you'd expect shorted valves would be in old radio's .
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