#1
Well, over the past few days my Mesa Mark IV has lost most of the gain in the lead channel; if I play at normal volume on any other channel then put it on lead, I can barely hear it and it isn't as distorted as it should be; all the controls are set right, but there's a quantity of missing sound.
Today while I was playing it, it started to hum louder than normal, then the hum began to increase rapidly in volume and I cut it off so it wouldn't blow up or something. Anyone have any idea what's going on? I'm horribly confused.
#2
Quote by ameer
Well, over the past few days my Mesa Mark IV has lost most of the gain in the lead channel; if I play at normal volume on any other channel then put it on lead, I can barely hear it and it isn't as distorted as it should be; all the controls are set right, but there's a quantity of missing sound.
Today while I was playing it, it started to hum louder than normal, then the hum began to increase rapidly in volume and I cut it off so it wouldn't blow up or something. Anyone have any idea what's going on? I'm horribly confused.

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#3
yeah, sounds like tubes, maybe the preamp tube associated with the lead channel or the driver. Powertubes are usually associated with volume drops and such, but since it's only happening on the lead channel, I would assume it's a preamp tube. Look in the diagram in the manual, and see which tube is associated with the Lead channel, and try swapping it with another to see if the problem stops on the lead, and starts where you put the bad preamp tube. Just an easy way to diagnose.
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#4
No luck. I tried swapping pretty much every preamp tube except the first in the chain, and it still does it.