[PrTv]

I've just received a pair of LM Ericsson 403B from an eBay seller. I bought some tubes from them earlier and I was impressed by their fast shipping and excellent quality tubes, so I didn't hesitate to buy again when I saw another pair on eBay (as a back-up pair).

But when I received the tubes, I started to doubt whether I made a right decision buying from them again, as I noticed 2 unusual things.

1. Inside of the tube, I saw white material coating the pins. I don't know if it's normal, but I've never experienced this with any other tubes in my possession.


2. On the silver deposit, I saw some white dot/marks. I don't know if this indicates that this is a leaky tube, as I read somewhere that if the tube is leaking, the silver deposit will turn white powder. In my case it's just little white dots.

Note that, in real life, the tip of the tube is not that black, and those white dots aren't this evident.

I already e-mailed asking the seller and below is what they said:

Quote:

The white substance that you see inside the glass on the pins is a normal occurrence from the soldering process and is typical on many Ericsson tubes.

They didn't answer my question about the white dots on the silver deposit.


I also test the tubes with my amp, and they seem to work normally. I also inspected the tubes in operation, and didn't find any unusual sign (no spark, crack whatsoever). Initially, I even detected a faint hum on the left channel, which went away after the 1st hour. I don't know if this is correct, but the hum may be one thing to tell me that the tube is new (in the case the hum goes away after some use).

I don't have much experience when it comes to tube, so I need your guys help on this.

 

[Fairbanks]

I had some LM Ericsson 2C51's at one time and they had a white substance also inside the tubes around the pin area.So the dealer is telling you the truth.

 

[davve]

Here's a pic on my LM 403B's

 

[jamato8]

Interesting reaction on the internal part of the pins. I have a few thousand tubes and haven't seen that before. The getter looks ok. Getter is always working to rid any molecules of gas that may leak in or that were left in the tube after vacuum.

On Tube Asylum on Audio Asylum there are some guys that might have a better idea of the white reaction material on the pins. Some tube have a special gas that was used during vacuum that can react. I once accidently broke a special Telefunken top getter tube that had a special gas (I don't know what it was) and I got sick.

 

[takezo]

i'm pretty certain the vacuum seal is breached near the glass enveloping
the pins... there is a very thin layer of silver deposit inside the tubes
which, when reacted with oxygen, turns powder white... the tube
may last a while if the breach isn't severe but it's not a good
feeling... this type of breach usually occur when we twist and
turn the tube pins in and out of tight sockets. "soldering process"?...
that's a fresh explanation...

 

[jamato8]

What turns white though is the flashed getter at the top. If the tube was very gassy then that silver getter would have turned white and even flaked off. If a thin getter then it can disappear totally but a thicker getter will turn white. Getter is about the only thing to turn white like that though so maybe some getter was flashed on the bottom of the tube and it has reacted? Is the top getter thinner than the other tube? I have seen getter not turn white but get thinner and thiner as it gets used up when binding to gas molecules.

 

[PrTv]

Thanks for your replies.

From you guys replies, I seem to have a bad luck owning a pair of bad tubes.

I don't know why they did this. I mean, they seem to be a reliable seller who reply fast, ship fast and pack the tubes very well with almost 100% positive feedback on eBay. My last transaction with them was really satisfactory.

This makes me wonder if the tubes are "really" match pair as described.

jamato8, thanks for the suggestion about the additional sources. I've just post this question on Tube Asylum.

Maybe it's time to give someone a negative feedback.

 

[jamato8]

Quote:

Originally Posted by PrTv /img/forum/go_quote.gif Thanks for your replies. From you guys replies, I seem to have a bad luck owning a pair of bad tubes. I don't know why they did this. I mean, they seem to be a reliable seller who reply fast, ship fast and pack the tubes very well with almost 100% positive feedback on eBay. My last transaction with them was really satisfactory. This makes me wonder if the tubes are "really" match pair as described. jamato8, thanks for the suggestion about the additional sources. I've just post this question on Tube Asylum. Maybe it's time to give someone a negative feedback.

I would give him a change to replace them.

 

[roger_s]

Try and find someone with a tube tester while you're negotiating with the seller. They could be bad or it could be getter residue. Some number from a tester would be most helpful in your negotiations.