AD30TC combo ???

sawyer722 · Post by **sawyer722** » Wed Sep 15, 2004 1:55 am

Hey guys,

I am getting a lot of hissing and crakling through my combo. So, instead of running it into the combo speaker I ran it through a Marshall 4x12 1960A cab and it went away. COuld this problem come from the transition wire between the amp and the speakers or just the speakers. If anyone can help that would be great

fiveightandten · Post by **fiveightandten** » Wed Sep 15, 2004 4:04 am

It's more likely that you have a bad tube that's crakling when it gets vibrated from the amp being cranked up. When you disconnect the internal speakers and play it through a 4x12 that the amp isn't touching, the tube isn't vibrating anywhere near as much, thus the crackling goes away.

It's also possible that the crackling could be a bad solder joint, or a bad component...but usually not the case in a newer amp.

-Nick

sawyer722 · Post by **sawyer722** » Wed Sep 15, 2004 4:18 am

which type of tube would it be that is causing the trouble? Pre-amp, Power, or Rectifier? I just changed the pre-amp tubes...but it has been doing this for a while

Andy H. · Post by **Andy H.** » Wed Sep 15, 2004 7:26 am

If it was unchanged with a change of pre amp valves I'd suspect the power valves next. You could check for this by warming the amp up and <i>gently</i> tapping each tube with a pencil or wooden chop stick to see if you can provoke the problem. If one or more tubes cause crackles then you'll know what's up. If so, I'd ideally replace the lot.
Let us know.

Andy.

Post by **bclaire** » Wed Sep 15, 2004 12:48 pm

also could just be a <u>loose</u> tube

AD30TC combo ???

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