[xenithon]

Hi all.

I noticed something when looking at the preamp tubes in my WA2 tonite. I purchased these about a month ago (Philips Miniwatt E88CC gold pin) - they were NOS, unused, fully tested, from a reputable source. They sound glorious. Both of them have the silver cap at the top of the tube, but I noticed that one of them - underneath that silver cap - is a little smokey. It is quite dark (almost black)...similar to when you hold a candle next to some glass and that black layer of soot forms on it.

It does not seem to be affecting the sound in any way (crackling, noise, imbalance, hum)…..they sound fantastic. But I wanted to double check if anyone knows perhaps what this may be. It was not like this when they arrived (both were clear) and it seems this built up with use over time.

I am primarily asking if this is something common, or something to worry about…..that is, if it may be a sign of potential tube failure and that I should take them out to prevent damage to the amp and attached components. I've includes some photos below.

Thanks in advance,
X

Clear:

Sooty:

Both

 

[Skylab]

Hi X:

I am not familiar with this specific tube, but I do have some GE 6DJ8's that look like this. It looks like getter flashing, although normally you wouldn't get additional flashing over 30 days I wouldn't think.

Do you have a tube tester?

 

[xenithon]

Unfortunately not, no tester. I got a reply from the seller that it is purely cosmetic; I am hoping so - and there has not been any affect on the sound.

 

[olblueyez]

Quote:

Originally Posted by xenithon /img/forum/go_quote.gif Unfortunately not, no tester. I got a reply from the seller that it is purely cosmetic; I am hoping so - and there has not been any affect on the sound.

I wouldnt worry unless the sound changes or it starts humming. Only thing I can imagine is sometimes when they sit for along time they can aquire air from sitting 20 30 40 50 years and the getter spewed on the glass?!?!? Either that or it is actively leaking and may need to be replaced sooner than later.

EDIT: If they came like this then I would not worry as no 2 tubes are the same but if this happened while in your possesion then it may have a problem. It has probably been like that since the day it was made.

 

[xenithon]

Quote:

If they came like this then I would not worry as no 2 tubes are the same but if this happened while in your possesion then it may have a problem. It has probably been like that since the day it was made.

They were not like that when they arrived. The seller said that it may build up over time (these were NOS, unused prior to installing in the amp).

 

[olblueyez]

Quote:

Originally Posted by xenithon /img/forum/go_quote.gif They were not like that when they arrived. The seller said that it may build up over time (these were NOS, unused prior to installing in the amp).

Seems to me that quick changes indicate death approaching quickly. I would tell the seller you want ot return the tube(s) or have him offer you an extended period in writing that will enable you to return the tube(s) if they fail in the next year. There are other tubes and if you paid alot of money then watch out for yourself.

I could be wrong but seems to me that a thing like that in a vacuum should not have big rapid changes. Like I said though if it sat for 50 years it could have been some air burning up and it may be fine. Based on price and disposition of the seller I would consider an exchange/return/warranty period.

 

[olblueyez]

Is this the same tube? These look kinda foggy.

 

[olblueyez]

I didnt realize how expensive they are, beautiful tubes (I love the gold pins) I know its silly but its cool. I have some sylvanias like that.

 

[xenithon]

No. Mine are Philips Miniwatt, made by Amperex in Holland. They are the normal E88CC gold pin, not the PQ.

As you can see in the pictures of each individual tube I posted about, the one is completely clear underneath the silver top; the other has the black residue.

 

[Oskari]

Quote:

Originally Posted by xenithon /img/forum/go_quote.gif No. Mine are Philips Miniwatt, made by Amperex in Holland. They are the normal E88CC gold pin, not the PQ.

Strictly speaking, they were not made by Amperex. If they are Dutch-made, they are Philips-made.

Amperex (at this point) was (one of) Philips group's US brand(s). Amperex used the PQ label which corresponds to the Philips SQ label. The E88CC is already a premium product above the ECC88 and these labels are probably just marketing.

 

[MD1032]

It almost looks like the foggy mark on the side of my RCA cleartop, but then again, that's because that's where the getter is located on the RCA tube. If the getter is larger on that tube and wraps over to the side, that might explain it, but otherwise I'm gonna go ahead and say that the tube must have a leak or something somewhere that is oxidizing the metals on the inside.

 

[atbglenn]

Quote:

Originally Posted by olblueyez /img/forum/go_quote.gif Seems to me that quick changes indicate death approaching quickly. I would tell the seller you want ot return the tube(s) or have him offer you an extended period in writing that will enable you to return the tube(s) if they fail in the next year. There are other tubes and if you paid alot of money then watch out for yourself. I could be wrong but seems to me that a thing like that in a vacuum should not have big rapid changes. Like I said though if it sat for 50 years it could have been some air burning up and it may be fine. Based on price and disposition of the seller I would consider an exchange/return/warranty period.

I totally agree. I would not feel comfortable with a tube that changed that drastically in the short amount of time you've owned it. Since the other tube looks fine, something isn't right. I would ask for a replacement.

 

[Oskari]

I would tend to believe what Jim McShane wrote.

 

[atbglenn]

Quote:

Originally Posted by Oskari /img/forum/go_quote.gif I would tend to believe what Jim McShane wrote.

Good to know, thanks