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
dover
2,243 posts
 
lewm
06-18-2016 2:39pm
Jea48, Gold-plated pins are a sure sign of recently manufactured tubes
This statement is completely misleading and not correct. I have many vintage tubes with gold plated pins - from Telefunkin, Mullard, Siemens and many others dating back to the 50’s
lewm
06-19-2016 6:10am
I think any one of us would say that no tube ever made has "gold" pins (as he describes them, carelessly)
No it is not careless, most experienced tube collectors refer to gold plated pins as "gold pins".

lewm
06-19-2016 6:10am
You cannot easily plate steel in the first place. So the notion of gold-plated steel does not make sense, either.
Again this is not correct. My understanding is that to gold plate steel you simply do a nickel plate process first and then flash gold plate over the top of the nickel base.
jea48
4,425 posts
 

lewm said:

"Based on the brief bit of researching I did do, my first thought is that this guy is incorrect as regards the composition of the pins and that he used the word "steel" without really thinking about it. Moreover, I think any one of us would say that no tube ever made has "gold" pins (as he describes them, carelessly); at best sometimes pins are gold-plated. Pure gold would be a terrible choice for a tube pin, because it is so soft. You cannot easily plate steel in the first place. So the notion of gold-plated steel does not make sense, either. "


WOW, right out of the gate you trash the man.

I am sure Joe S is quite aware the tube pin is gold plated. Just guessing he figured anyone reading his post knew that. Apparently not all though.

Joe’s Tube Lore

http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html

A lot of guys just say gold pins instead of gold plated pins. Surely you don’t think, they think, the pins are solid gold?

>>>>>>>>>>>>>>>


As for exactly what the base metal of the 9 pin miniature signal tube pins are made from all I have ever heard, when specking of the pin is steel. Why don’t you supply a credible Web Link what the pins are actually made from if not steel.


Note below these guys also refer to the pins as gold pins. I would be willing to bet a hundred bucks they know the pins are gold plated and not actually solid gold.

>>>>>>>

Brent Jessee

Quote:

"This is one of two premium versions of the 6DJ8 tube. First of all, it is the same tube as the 6DJ8, and will work wherever a 6DJ8 is needed. It has premium features such as low noise, low microphonics, and usually a longer lifespan. Sylvania made a version that is JAN military spec without gold pins. Amperex made all of theirs with gold plated pins and most have the PQ shield logo, standing for Premium Quality. See note below about Amperex 6922 and Bugle Boy tubes. Some of the later gold pin Amperex have the orange world logo."

http://www.audiotubes.com/6dj8.htm


Notice Brent did say gold plated once, and just gold pins twice. I am pretty sure he knows the pins on Sylvania are gold plated and not solid gold.

>>>>>>>>>>>

"Amperex "PQ" 6922 - Super super rare gold pin 6922 with tall bottle made in 1960"

http://www.upscaleaudio.com/6922-6dj8-7308-pcc88/amperex-6922-tall-bottle-1960-s-vintage-made-in-usa...


I would be willing to bet Kevin knows the pins are plated and not solid gold.

>>>>>>>>>>>>

New Sensor

Standard Electro-Harmonic 12au7EH

http://www.newsensor.com/ProductHighLight.aspx?ProId=30


Electro-Harmonic-Gold

http://www.newsensor.com/ProductHighLight.aspx?ProId=32


New Sensor just says gold.

>>>>>>>


Best regards,

jea48

rpf
76 posts
 
Several points:

From Jim McShane (an excellent tube dealer) on AA:

"Do yourself a favor - clean the tube pins and sockets every time you change tubes. A bottle of DeOxit D5 and a handful of good old fashioned pipe cleaners works great for octals and other large pin sockets; for the miniatures, D5 and the little tiny dental brushes for cleaning between your teeth (another drug store item) do a solid job. BTW, D5 is good to 400F - so don’t lose sleep over it because of something you read on the "Hi-Fi Hysteria" forum. And it doesn’t gum up either. Spray some in a paper cup and let it evaporate - you’ll be able to see for yourself.

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!!"

Alcohol really isn’t enough to clean with. Old tube pins also often really need to be scrapped. A dental brush can work but sometimes I use a small Exacto knife. You’d be surprised what occasionally comes off.

On the other hand, I’ve tried more than half a dozen NOS Mullards (purchased from several sources) in the pre-amp section of my Cronus Magnum (which takes just one pre-amp tube) and all have started to get noisy within a month or so. Various short plates, long plates, 12AU7s, CV4003s, from various factories; it hasn’t mattered.

I also tried NOS Amperex and Radiotechnique (both, like the Mullards, made by Philips). The Amperex also started to get noisy: the RT (platinum grade from Upscale Audio: several over several years) have stayed quiet. Some of the Mullard CV4003s were Platinum Plus ("CJ Test") grade tubes from Upscale. Supposed to stay quiet in hard on tube pre-amps from the likes of CJ, Rogue and Sonic Frontiers. They didn’t. I don’t blame Kevin. I’ve just come to the conclusion that the Cronus and NOS Mullard are incompatible: I don’t know why. They certainly work in other pre-amps owned by many people. (For the record, NOS RCA/Raytheon 12AU7 black-plates and RCA/GE 5814s also stay quiet).

In addition, I’ve purchased tubes from Alfred Kayser and found him knowledgeable and fair. The very short plate CV4003s he sold me also started to get noisy in the Cronus pre-amp slot - but they took longer than even the Upscale Platinum Plus. Luckily the 12AU7 driver section of the Cronus has a significant effect on the sound and all of the Mullards that didn’t make it in the pre-amp slot went to the former section over time and sound(ed) great there. I also bought several NOS Mullard rectifiers from Alfred (back when I had gear that took them; mostly Modwright) and they all performed perfectly.



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!
jea48
4,425 posts
 

From Upscale Audio

Quote:

"I have a brand new tube that’s noisy. When I put my old tubes back they worked fine. This tube is defective.

Okay... I know this one’s not really a "question" but we get it so often that it needs to be addressed anyway. Many times when a piece of tubed equipment is noisy, the cause is a bad connection between a tube and the socket, not a noisy tube. In fact, the majority of tubes we have returned to us for warranty replacement, are not noisy at all!

Remember: Tube stockets are not highly reliable connectors! If the sockets are dirty or not tight enough, or if the pins are slightly "thinner" than your original tubes, or have a little grime on them, it can cause one or more pins be unable to make solid contact. This can result in noise.

So... make sure your tube pins are clean before plugging them in. Also, make sure your sockets are clean and tight. Many times, just the act of removing a tube and re-seating it, either in another position or back into its original spot, can alleviate the problem. You might also try gently twisting the tube in its socket, to make sure it’s getting a solid connection on all the pins."


Copy and paste between brackets.

]http://www.upscaleaudio.com/technical-help/tube-faq/[

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