Early Versus Late Animals

soundmasterg · Post by **soundmasterg** » Mon Jul 11, 2005 7:27 pm

Its not the power tubes Bob....its the pins in the tube socket needing tightening. The only way the tubes themselves are crackling is if they are internally shorting, in which case they need to be replaced before they blow. Its very common for tube sockets to need retensioning, especially in older amps that have been moved around a lot.

rictified · Post by **rictified** » Tue Jul 12, 2005 4:52 am

I just pulled two old old 6L6's from an old Ampeg which was crackling, which I thought had a bad connection somewhere, as soon as I changed them the crackling stopped and they weren't shorting. But when power tubes crackle it is usually after they warm up not before. Power tubes will also crackle when the bias is set incorrectly especially after they age.

soundmasterg · Post by **soundmasterg** » Tue Jul 12, 2005 9:25 am

It could also be that the new tubes pins are a slightly different size so they fit into the sockets better. Or it could be that the tube pins and/or sockets needed to be cleaned and pulling the old tubes out disturbed whatever dirty connection was there enough to where it makes better contact now. In my experience, unless there is something wrong with the tube to where it would need replacement, like an internal short for instance, then any noise you would think is the tubes is just dirty sockets, or sockets that need to be retensioned, or dirty pins on the tube.

rictified · Post by **rictified** » Tue Jul 12, 2005 9:59 am

It was definitely internal, they were very old tubes and needed replacement, wouldn't crackle for about ten minutes then would gradually get worse and worse. But I've also had good SVT power tubes crackling that went away with a bias change, google it, there are instances where power tubes will crackle, I don't know why, but they do. It's not a common occurance but it does happen.