blackba
Well-known member
Both times I have had power tubes go bad, it they have started crackling. The recent JJ 6L6 that went, had the plates glowing a bit red and would throw the bias way off. I generally have some my amps before I need to replace the power tubes, now that I am starting to keep them longer, I am on the lookout for power tube issues.
Generally when the power tubes are going, they start to sound dull and lack bass. I had a set of GT EL34's that were just poorly matched when I checked them. I replaced them and the amp sounded better than it had in years.
There seems to be 2 camps of people with strings and tubes. Those who change them on an interval, (ie every year for power tubes, or every week for strings) and those who try to get the max life from the tubes and strings. I would fall into the later camp.
One thing to keep in mind as well. When you move a tube amp, make sure it has had enough time to cool. I moved my mark IV from the recording studio back home. When I fired it up again, I had a bad tube. I moved it while it was still warm and I think that was my issue. The power tube could have been going too, but I bet I sped up the process.
Generally when the power tubes are going, they start to sound dull and lack bass. I had a set of GT EL34's that were just poorly matched when I checked them. I replaced them and the amp sounded better than it had in years.
There seems to be 2 camps of people with strings and tubes. Those who change them on an interval, (ie every year for power tubes, or every week for strings) and those who try to get the max life from the tubes and strings. I would fall into the later camp.
One thing to keep in mind as well. When you move a tube amp, make sure it has had enough time to cool. I moved my mark IV from the recording studio back home. When I fired it up again, I had a bad tube. I moved it while it was still warm and I think that was my issue. The power tube could have been going too, but I bet I sped up the process.