Having problem with tubes

[tdogzthmn]

One of my tubes has developed a problem where it begins to cause static in the channel.  Even with the volume all the way off there is a noticeable static coming through the speakers.  I have swapped the tube and confirmed that static occurs on which ever side is using that tube.  I had the same issue a few weeks back although it had seemed to settle down again and play without issue.  I wanted to know if there might be something else to check or if its just a tube that's going bad and needing replacement. 

[Doc B.]

Yup, they just do that sometimes.

[tdogzthmn]

Are you saying I will need to replace them or wait and see if the issue resolves itself again?  The amp is only a few months old so I cant imagine I've burned through the tubes useful life already.

[Doc B.]

It's simply about the variability of tubes. Some just get noisy whether they have had a lot of use or not. And a worn out tube may still be dead quiet, but the big difference with a worn tube is that the sound will usually be less dynamic and more prone to harmonic distortion.

[Paul Birkeland]

If I have a tube that does that, and I am 100% sure it's the tube, I will leave the piece of equipment on for 3-6 weeks and let the tube cook like crazy to see if it will settle down.

In the case of the 6DN7, I'd just buy 5-6 to have around as spares since they aren't particularly expensive.

-PB

[azrockitman]

sorry to tag on but where is a good place to "stock up"?

[jimiclow]

tubesandmore.com

[tdogzthmn]

I've had problems finding sources for these tubes as well. If someone could point me towards a reliable source I'd appreciate it! On the upside I've gotten less hum the past two days so it might be that things are settling down again. I would say the amp and tubes have around 400 hours on them so far. 

[Paul Birkeland]

It looks like Antique Electronics has plenty of these.

-PB

[FraGGleR]

These guys have good prices and will match pairs if you want for $2 extra a tube (no idea if necessary, but was cheap enough for peace of mind):  http://www.thetubecenter.com/vacuumtubes_tubelist_tubes_6d4-6jz8.html

[azrockitman]

Thanks to all for the tips!