2. analog
  3. 125078-1452

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

Showing 4 responses by czarivey

czarivey
5,946 posts
 
The long story short, 
If you're onto NOS tubes, have a tube tester and shop for'em at thrift stores selling old tube radios for cheap. Purchasing them from dealer is big risk.
Purchasing NOS on internet is risky no matter how reputable the seller is.
Another useful tool to use NOS tubes is VARIAC transformer to bring NOS tubes SLOWLY up to operating voltages when you mount them first time no matter how good these tubes test.

Other than that, there are plenty of options to void NOS and to purchase just brand new tubes 
czarivey
5,946 posts
 
The NOS may have 125 hours of use.
Is there any sort of odometer in vintage NOS tubes?
czarivey
5,946 posts
 
well i mostly deal with solid states, not tubes and once i've ordered a set of NOS transistors via ebay. they came to me with clear signs of being mounted onto the heatsink(dry traces of heat sink compound!) so it looks like NOS isn't really NOS but perhaps UOS with unknown hours.

czarivey
5,946 posts
 
Sometimes you swap a tube and the new tube is okay. so the tube you removed must be bad, right? NO! Sometimes the scraping action of removing and reinstalling a tube in that socket is enough to temporarily restore contact - and fool you into thinking you have a bad tube! KEEP YOUR SOCKETS CLEAN!!"

Once a blond girl goes into her nice bmw coupe and it does not start. She wiggles key back-forth pushes pedals jerks shift knob, but no success.
Another blond girl comes by and asks what's the problem....
Than she asked:
-- Did you wipe your dashboard?
-- Yes
-- Did you wipe your headlights and bumper?
-- Yes
-- Did you wipe your wheels and shined your tires?
-- Yes
-- I'm sorry I have no idea why it doesn't start than!
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