Help please! Mark IV static sound on low E string.

[giantstepjoe]

My Mark IVb combo has started giving me problems. It has an intermittent issue where there is a noticably annoying static/ crackle sound on notes played on the low E string ranging from an open E to a g#. It is most noticable on the clean channel. I tried swapping out v1,v3, and v5 with a tube known to be good and changed the power tubes and no dice. I then tried cleaning the eq sliders because I noticed that when I moved the 80 slider the noise would go away and then come back. After cleaning the sliders the sound was would go away for a short time but then it woul eventually return. Sometimes when the amp has been running for a while and is good and warmed up the sound will go away but it always returns the next time I power it up. I know I should try to change the other 12ax7s just to rule them out. Anybody encounter this issue before or have any ideas? Much appreciated.

 

[HBob]

This probably won't help but I had some weird static on certain notes on the clean channel and it turned out to be that the input on a digital reverb rack unit was being overdriven. Almost sounded like fret buzz. Turned down the input level on the reverb unit and it went away.

 

[giantstepjoe]

Thanks! Mine does it with no effects of any sort.

 

[Archlute75]

My Mark IVb combo has started giving me problems. It has an intermittent issue where there is a noticably annoying static/ crackle sound on notes played on the low E string ranging from an open E to a g#. It is most noticable on the clean channel. I tried swapping out v1,v3, and v5 with a tube known to be good and changed the power tubes and no dice. I then tried cleaning the eq sliders because I noticed that when I moved the 80 slider the noise would go away and then come back. After cleaning the sliders the sound was would go away for a short time but then it woul eventually return. Sometimes when the amp has been running for a while and is good and warmed up the sound will go away but it always returns the next time I power it up. I know I should try to change the other 12ax7s just to rule them out. Anybody encounter this issue before or have any ideas? Much appreciated.

Yeah man, not sure, but I have the same problem if I'm playing loud on the clean fat mode with the bass too high. I can't tell if it's only with the reverb on or not, but it seems to me like I'm pushing a tube to breakup somewhere with that low freq, but not a pleasant breakup. Almost like a farty, speaker breakup, but it's not coming from the speaker. I think it's a preamp tube, but I'm about to switch out my old EL34s for some new ones, so I'll tell you if it goes away then. Def the bass freqs though.