Crack "scratchiness" [resolved]

[denti alligator]

I'm getting a low-volume scratchiness sound in the Crack. Seems to be in both channels. Comes and goes. I've rolled a number of tubes. No difference. But it can be silent for hours and then suddenly come in. Tonight when I turned it on it was dead silent. Then after about 10 minutes the noise kicked in. But now, after another 5 or so, it's gone. Very strange. Any ideas?

No Speedball. Doesn't seem to change with volume.

[Deluk]

Refrigerator/freezer on the same circuit?

[Paul Birkeland]

This sounds a lot like a flaky solder joint, but one that's very close to working perfectly.  There's also certainly a possibility of power line contamination, as mentioned by Deluk, or some self noise in one of the tubes.

-PB

[denti alligator]

I've been away and not using the Crack, but this problem persists. I'm pretty sure it's the 6080 tube, because when I tap it the scratchiness comes and goes. Should I try the solder joints for that tube, or might I have a damaged tube?

[Paul Joppa]

That mechanical sensitivity strongly suggests a connection problem, usually solder joints but sometimes loose socket terminals or corroded tube pins.

[denti alligator]

I don't think I've removed the 6080 since I first inserted it. I'll take it out a deoxit it and resolder the joints and clean the sockets, too. I'll report back if it's still noisy.

[Rhok]

I had the exact same issue, reheated all solder joints and it didn't resolve, rolled numerous tubes and it didn't resolve - lived with the issue for months.. ended up being my router being too close to it (figured this out when buying a new router and moving it around).

I now have my amp as far as reasonably possible and have not had the issue occur since.

[denti alligator]

I had the exact same issue, reheated all solder joints and it didn't resolve, rolled numerous tubes and it didn't resolve - lived with the issue for months.. ended up being my router being too close to it (figured this out when buying a new router and moving it around).

I now have my amp as far as reasonably possible and have not had the issue occur since.

My router is close by, so I'll try shutting it off. Thanks for the tip!

[denti alligator]

I've not used the Crack in months. But this problem persists. Moving it to the other side of the room (it was near the router) didn't help.

I've reflowed all the joints. I've cleaned sockets and pins on tubes. I've swapped out the 12AU7.
Volume has no affect on the noise. It's audible with the volume turned all the way down.

The 6080 tube seems to be the culprit. Any other suggestions?

[Rocketman248]

Have you tried another 6080?

[denti alligator]

Have you tried another 6080?

No. But I may be able to today. I'll report back.

[denti alligator]

Just tried it with another 6080 and indeed, it was the tube!