Bad NOS tubes...

aolmrd1241 said:

"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. "

~~

As someone earlier said the tube pins could be dirty. I would clean the tube pins with Isopropyl Alcohol. Then try them again.

I would like to know how the OP was able to determine all 4 tubes are defective.

I would suggest he find someone in his area to check the tubes.

I can't imagine buying vintage tubes and not owning a tube tester.

~~ 

The OP said he reinstalled 4 of the original tubes that came with the amp and the amp sounds fine again. I wonder if he then pulled one of the good tubes and then installed one of the bad tubes in it's place and then took a listen? (After cleaning the tube pins first).... If that tube did sound bad then pull it and try another supposedly bad tube and then listen to it again. Repeat the process until he has gone through all 4 tubes.

(Note: I don't know if this amp requires closely matched pairs of driver tubes. Or  closely match sections of each driver tube.)

~~

To the OP. I suggest you send an email to the tube vender you bought the tubes from with a Link to this thread. I think it's only fair the guy should have the right to defend himself.

aolmrd1241 said:

Pins were clean.

Did you clean them?

When were the tubes manufactured? Gold plated steel pins I assume?

How tight do the pins of the tubes fit the tube socket female contacts?

Did your tubes come boxed like this?

Copy and paste between the brackets.

]https://www.youtube.com/watch?v=YfBTlJBWoGw[

lewm,

Here is some reading material for you.

http://www.audioasylum.com/scripts/d.pl?audio/faq/joes-tubes.html#6DJ8

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

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/[

It appears the pins on a miniature tube are made of Kovar.

I posted a message asking the question and here is one of the responses I received.

Posted by Steve O (A) on June 19, 2016 at 12:44:03 In Reply to: RE: Most commonly it is not steel, but... posted by jea48 on June 19, 2016 at 08:38:44:

The term "steel" doesn’t always get used in the strictest metallurgical sense. I think steel is commonly used to describe the pins because they’re usually quite magnetic. The material I’ve seen referenced in tube manuals and such is "kovar", a nickel/cobalt/iron alloy with coef of thermal expansion similar to borosilicate glass. The alloy also bonds well to glass and is apparently magnetic too. Seems if one believes magnetic conductors distort music signals, tubes should not be in the signal path...LOL.

http://www.audioasylum.com/audio/tubes/messages/26/269123.html

http://www.audioasylum.com/audio/tubes/messages/26/269119.html