Intermittent Static/Crackling

[Jake1]

I've been using my amp with speedball for about 6 months now and just recently there's been a new intermittant buzzing/crackling sort of noise.  I've gone through and tapped all of the wires with headphones plugged in and it seems to make no difference.  It seems totally random and will be awful for a few minutes then completely silent for another few minutes.  I was wondering if anyone had any advice to fix this. 

Thanks

[Doc B.]

Could be outside interference like a cellphone GSM buzz or an appliance turning on.

[Nignoog]

My post is right below yours. I’m having a simiar (or the same) problem. My short term fix is tapping on the chassis to the right of the vent. Hope we get our problems resovled.
Are you in a humid environment? I live in NYC and wonder if it’s weather related.

[Jake1]

Yeah tapping on the chassis in different places works sometimes, sometimes tapping the tubes fixes it I really can't see much pattern to it.  I'm in Ohio so it isn't super humid or anything.  I've got a new input tube coming Monday so I'll update if that makes any difference.  Is there a way to check if it's cell interference?  I haven't had any issue like this so I'd tend to think it isn't an appliance in my house as that would have shown up earlier.

[fromnowon]

I don't know if this helps or not, but when I had my Crack near my computer (desktop PC), on the same surface / desktop as the computer processor, the Crack was picking up some noises.  I noticed that if I lifted the plate up out of the frame the noise would change and go away, if I lifted the plate up an inch or so.  It was weird.

Anyway I moved the Crack away from my computer and put it on a different piece of furniture.  It's been really quiet since.

[Paul Joppa]

You can also wiggle the tube, which will often show up a problem with the socket. Usually that means dirty tube pins or a marginal solder joint on the socket lugs. As with the chopstick test, use the crappy 'phones in case it makes a LOUD noise!

Less likely, but it does happen occasionally, a tube itself will make sporadic noises. If the tube has not been in operation very long, such noises often stop after 100 hours or so of burn-in, but rarely it will indicate a tube going bad. I've only personally experienced the latter with older, low-grade tubes from China, but it shows up on the web now and then.

On the radio-frequency interference question, if there have been no changes in your house (no new cell phones, light dimmers, refrigerators, etc.) it is still possible that a neighbor has something new.

[Jake1]

So I went back through and tapped everything with better headphones and there was a really quiet change when tapping the wires on the 6080 tube.  I hit one spot and got a single loud pop and now the static is totally gone.  Not really sure what happened but I guess my worse headphones weren't loud enough to find the problem.  No idea how tapping it fixed it but I tapped multiple times and the static won't come back so I'll take it I guess.  Thanks for the advice!

[Deluk]

I recently had some low fizzing noticeable in the quiet between music tracks. Cured by tightening down the transformer bolts. Surprised to get half a turn on 2 bolts and three quarters of a turn on the other 2. Just tweaked them with a screwdriver without trying to hold the nuts. Think I'd put this down as maintenance, so a worthwhile check for other Bottle Headers.

[Paul Birkeland]

I hit one spot and got a single loud pop

That is an indicator of where you would want to reflow your solder. (Both ends of that connection)