Dual Rec: Tube noise & which to replace?

[Sparco]

Greetings,

Using my Dual Rec, on any channel or mode, I'm getting some "white" noise coming through quite loud now, even with a noise gate.
I'm assuming its one of the tubes needing to be replaced but have no idea how to tell which one it is, Rec, Power or Pre?
Is there a way to diagnose this at home without bringing it in just to have a tube replaced? Any help would be greatly appreciated!

Sparco

 

[domct203]

Sounds like a preamp tube. If it is in all channels it is most likely the (input stage) V1 position. This is one of the smaller (12AX7) tubes, the one closest to the input jack.

It could also be your FX loop driver V4. Try hard bypassing the loop and see if the noise stops.

Either way I suggest getting one or two preamp tubes to trouble shoot with. Start by swapping a new tube into the amp one position at a time. When the noise goes away you have found the bad tube. I'll bet it's V1 ?

Dom

 

[Sparco]

Cool thanks man, I'll give that a try! Noise is gettin pretty **** loud too.