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Bad NOS tubes...

I just want to put this out there...as much as I would not like to...my head says otherwise. Tube buyers beware!!!

On 3/7/16 I bought 6 NOS Mullard 12au7 4003 tubes for my preamp from a vender out of Minesing, Ontario Canada... under the store front name of ’mullard.com’ http://www.mullardtubes.com/Mullard-ECC82-12AU7-CV4003/?ID=0&ProductID=153 and ’ tube products.com’ http://www.tubeaudioproducts.com/Mullard-Brimar/ProductDetail.aspx?CatID=65&ProductID=153#

The owner is one Alfred Kayser. On his site/sites he states all of his tubes are tested and matched for best performance values. Well,I went ahead and ordered and received said tubes. After 2-3 months of use I started to hear unacceptable levels of noise from my speakers,you know, the dirty sound of that dreaded tube noise of a scratching, distorted, dirty volume pot type of noise,which totally infringes upon the music. I went ahead and called Alfred and asked him about it and he just responded there is "nothing he could do" for me. Hey,no problem,but he advertised full-up tested tubes. If it was only one bad tube,I could understand,I’m a realist...things happen.

But!!!

Long story short,I came to find out that four of the six tubes are defective and are not what I paid for. Two are fine. So the moral of this story is...When buying tubes,do not go the cheaper route,find and use a "reputable" tube vender and save yourself some time,money and aggravation. Of course I will never use this guy again for any of my audio needs... Hope this is of some help to the Audiogon membership.

aolmrd1241
aolmrd1241 OP
1,042 posts
 
Hello,and thanks for the replys. I put the stock tubes back in place that came with the pre and have had not so much as a burp from them. The two good nos tubes have seen time in the driver stage and are quiet as a mouse. So I do believe the four bad nos tubes are very much defective.
lewm
13,107 posts
 
The driver stage is typically low stress, and, since there is no gain in the driver stage, most likely to be "quiet".  Try the "bad" tubes in the driver stage and let us know what happens.  What is the vintage and brand of the original set of "stock" tubes? 
jperry
2,450 posts
 
"aolmrd1241, So the moral of this story is...When buying tubes,do not go the cheaper route,find and use a "reputable" tube vender and save yourself some time,money and aggravation."

Absolutely true, it is tempting because the prices from reliable vendors is not inexpensive, but the value is there when you use the right vendor. 
rodman99999
6,158 posts
 
You used the tubes and they functioned properly for HOW LONG? I have no problem at all, with the idea that those tubes tested and sounded, "NOS", when checked by the seller. How is he supposed to know what they will do, in your equipment, after sixty to ninety days? If there exists a tube vendor, that will warranty NOS, small signal tubes after that length of time, I want to know their name. I’ll be purchasing from them too.
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cleeds
5,957 posts
 
Periodic problems with tubes - including both noise and catastrophic failure - are inherent in their use. While getting only two or three months from a tube seems like poor service, it does happen. It's happened to me. Over the long term, there's probably no avoiding such a result unless you're very, very lucky.

Users who don't have the patience, budget or disposition to cope with tube problems probably should avoid tube products altogether, imo. They'd be happier that way.

Last month, I replaced a failed 6550 in my preamp after only 260 hours of service. Oh well!
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