Mark V crackling noise

[rustinpeace117]

Hello all,

I recently installed some new E34L power tubes into my Mark V (before you say anything, they were matched by the guys at eurotubes so they can be used on the el34 switch), and through all the channels, mainly 2 and 3 though, I am hearing a crackling noise with no signal into the amp and loop. I dont have another set of power tubes to swap out, and I have tried replacing all preamps 1 by 1, and still no solution. 10 watt setting seems to get the worst crackling as well.

Still hear crackling with reverb turned off and all pots turned down. Still there with fx loop hard bypassed. Still there with triode/pentode and/or tube/diode rectification.

It only seems to go away slightly if I switch to variac power, which leads me to believe its something with these new power tubes.

Any help with isolating the cause of this would be appreciated, thanks!

 

[SteveO]

If it didn't crackle before replacing the power tubes and it does now, I'd say that would be the first thing to check. That means swapping those tubes out to see for sure, there's no shortcut to that.