Question about tubes + Noise issues

[calmiswar]

After a lot of hiccups, I finally managed to have a working amp a week ago. Everything sounded great and then all of a sudden, there was noise. Annoying noise.
It starts off as a rushing sound, then rustling, pops and then full on static. It could be quiet for 15 mins and then all of a sudden, the noise starts. Not affected by the volume knob either.
The solder joints seem fine, although I'll probably be reflowing everything this weekend.

I had a question about the driver tube (Svetlana Winged-C). Could it be the cause of this noise? And I closely inspected the tube today, I see what looks like blackening near the silver coating at the base. Also, there seem to be deposits along the sides of the tubes. Have attached some pics.
Do you think the tube is bad and causing the noise issues?

The tube I received in the stock kit went bad too, it went totally cloudy white at the top. Now if even this one has gone bad, then either I'm very unlucky with driver tubes or could there be anything wrong in my crack causing this?

Thanks for reading.

[calmiswar]

pic

[calmiswar]

Blackening

[Tom-s]

It starts off as a rushing sound, then rustling, pops and then full on static.

It sounds like a solder joint problem to me due to heat.
Do a chop-stick test on the solder joints when the problem occurs.

[Paul Birkeland]

It is impossible to tell if a tube is noisy by looking at a photo.

The noises you are describing sound a lot like a cold solder joint.  When you're listening to the amp, tap really hard on the top plate to see if that actuates the noise (do this with some cheap, disposable headphones on).  When I build a new piece of gear, I will get it running on a test setup, then bang on it nice and hard with my knuckles as a way to test the solder joints.  If there's no noise or dropping of signal, this is a good sign for your solder joints.  If you get static, popping, or dropped signal, then you have a little more work to do under the hood.

-PB

[calmiswar]

Looks like you guys were right. Redid the soldering at the 8 pin socket. Seems to be quiet now. Thanks for the help.

But, I was concerned about the driver tube. The voltage at the terminals 2 & 4 is 180V. Do you think it is nearing death?

EDIT: I meant the 9 pin socket, the one with the satanic LEDs.

[Tom-s]

What are the voltages @ 1 and 5?

[calmiswar]

What are the voltages @ 1 and 5?

Around 81-82V.

[Tom-s]

Not the best tube, but if it sounds good, it's good.

[calmiswar]

Not the best tube, but if it sounds good, it's good.

Thanks.

My only worry is they'll fail when I'm listening to music and blow my headphones.

[Tom-s]

At the end of life it won't blow. The sound will become weird/distorted/flat. Never had this as of yet (way too much tube rolling  ).

[calmiswar]

At the end of life it won't blow. The sound will become weird/distorted/flat. Never had this as of yet (way too much tube rolling  ).

That's encouraging.

[attmci]

It is impossible to tell if a tube is noisy by looking at a photo.

The noises you are describing sound a lot like a cold solder joint.  When you're listening to the amp, tap really hard on the top plate to see if that actuates the noise (do this with some cheap, disposable headphones on).  When I build a new piece of gear, I will get it running on a test setup, then bang on it nice and hard with my knuckles as a way to test the solder joints.  If there's no noise or dropping of signal, this is a good sign for your solder joints.  If you get static, popping, or dropped signal, then you have a little more work to do under the hood.

-PB

Paul, you are so funny. But that's the way to find a cold solder joint. Don't trust your eyes. 

Cold Joints

Nope, we're not talking about arthritis, or rolling a blunt in the Seattle snow. We're talking about cold solder joints, that is, a solder joint that does not conduct properly. They are one of the most common reasons your new build doesn't measure right (along with mis-wired terminals).
 
Sometimes you can see a cold solder joint. It might look dull and crystallized or you might see that a wire hasn't been well covered with solder. But lots of times you can't see a cold joint. Don't trust your eyes. It takes all of a few seconds to reheat (or reflow, or rewet) a solder joint. And in fact when a kit arrives at our lab for repair it's pretty much standard operating procedure for our techs to 1) verify component and wire connections and 2) go through and reflow all the joints in a kit - before removing and replacing any components. Often that's all a build that isn't working right needs. Make sure your soldering iron tip is clean, otherwise you will be holding the tip to the work longer than necessary and possibly leaving more residue to further increase the resistance of the joint.

[calmiswar]

Paul, you are so funny. But that's the way to find a cold solder joint. Don't trust your eyes. 

It's outright genius! Works like a charm.

[Paul Birkeland]

Around 81-82V.

That's completely reasonable.